theoretical implications on visual (color) representation and ...

ACTIVITAS NERVOSA SUPERIOR

Activitas Nervosa Superior 2013, 55, No. 1-2

IDEAS & P ERSPECTIVES

THEORETICAL IMPLICATION S ON V ISUAL (COLOR) REPRESEN TATION AN D CYTOCHROME O XID ASE BLOBS István Bókkon  and Ram L.P. Vimal V ision Research Institute, Lowell, M A , USA

Abstract The rich concentration of m itochond rial cytochrom e oxid ase (CO) blobs in the V1 (striate) pri m ate visual cortex has never been explained . Although the d istribution of CO blobs provid ed a persuasive exam ple of colum nar structure in the V1, there are contrad ictions about the existence of hypercolum ns. Since photoreceptors and other retinal cells process and convey basically external visible photonic signals, it suggests that one of the m ost im portant tasks of early visual areas is to represent these external visible color photonic signals d uring visual perception. This representation m ay occur essentially in CO-rich blobs of the V1. H ere w e suggest that the representation of external visible photon signals (i.e. visual representation) can be the m ost energetic allocation process in the brain, w hich is reasonably performed by the highest d ensity neuron al V1 areas and m itochond rial-rich cytochrom e oxid ases. It is also raised that the functional unit for phosphene ind uction can be linked to sm all clusters of CO –rich blobs in V1. We present som e im plications abou t d istinction betw een the physics of visible photons/ light and its subjective experiences. We also d iscuss that am od al and m od al visual com pletions are possible d ue to the visual percep tion ind uced visualization w hen the brain tries to interpret the unseen parts of objects or represent features of perceived objects that are not actu ally visible. It is raised that continuously prod uced intrinsic biolum inescent photons from retinal lipid peroxid ation m ay have functional role in initial d evelopm ent of retinogeniculate pathw ays as w ell as initial appearance topographic organizations of V1 before birth. Finally, the m etaphysical fram ew ork is the extend ed version of d ual-aspect m onism (DAMv) that has the least num ber of problem s com pared to all other fram ew orks and hence it is better than the m aterialism t hat is currently dom inant in science. Key w ord s: Color representation; V isible electromagnetic photons; A modal and modal visual completions; COrich blobs in V 1; Phosphenes; M etaphysics; M aterialism; Dual-aspect monism; V isual channels

1. IN TROD UCTION The attribu tes of visible electrom agnetic p hotons, su ch as w avelength and intensity, are p hysics, bu t both exogenou s (stim u lu s/ light d ep end ent) and / or end ogenou s (su ch as p hosp henes) colors are su bjective exp eriences related to its attribu tes hu e, satu rat ion, and brightness (Vim al, Pokorny, & Sm ith, 1987). When w e talk abou t ou r visu al p ercep tion, in reality, w e talk abou t the p ercep tion/ d etection of external electrom agnetic visible p hotons. Althou gh external visible p hoton signals that are conveyed to V1 can be m od u lated by other 

Correspondence to: Istvan Bokkon: [email protected]; url: http://bokkon-brain-imagery.5mp.eu Received January 17, 2013; accepted February5, 2013; Act Nerv Super (Praha) 55(1-2), 15-37.

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sensory m od alities d u ring m u ltisensory integration (Calvert, Sp ence, & Stein, 2004), it is hard ly qu estionable that p hotorecep tors and other retinal cells p rocess and convey p rincip ally external visible p hotonic inform ation to Lateral genicu late nu cleu s (LGN ) and then to V1 (p rim ary visu al cortex) and other visu al areas. It su ggests that one of the m ost im p ortant tasks of early V1 area is to rep resent these d etected external p hotonic signals. Althou gh vision science m akes d ifference betw een achrom atic and chrom atic vision, how ever, both are su bjective color exp eriences p rod u ced by m ixed visible (color) p hoton signals in the hu m an eye ranging from abou t 400 to 700 nm . Exp licitly, in the follow ing sections, w e p oint ou t that the rep resentation of external visible p hoton signals (i.e. visu al rep resentation) m ight be one the m os t energetic allocation p rocesses in the brain, w hich is reasonably p erform ed by highest d ensity neu ronal V1 areas w ith m itochond rial-rich cytochrom e oxid ase (CO) areas, w hich send signals to visu al 2 V4/ V8/ VO color-related -neu ral-netw ork. It is also raised that sm all clu sters (3-4 blobs/ m m ) of CO blobs m ight w ork as fu nctional u nits for consciou s p hosp hene p ercep tion. In ad d ition, w e p resent som e im p lications abou t d istinction betw een the p hysics of visible p hotons/ light and its su bjective exp eriences since the latter is the m ental asp ect of color -related -neu ralnetw ork-state; its inseparable p hysical asp ect is the V4/ V8/ VO color-related -neu ral-netw ork and its activities. We also argu e that am od al and m od al visu al com p letions are p ossible d u e to the visu al p ercep tion ind u ced visu al im agery w hen higher level regions in the brain tries to interp ret the u nseen p arts of objects or rep resent featu res of p erceived objects that are not actu ally visible. Then, it is raised that retinal biolu m inescent biop hotons origin ated from natu ral retinal lip id p eroxid ation m ight have im p ortant role in the d evelop m ent stru ctu ral organization of visu al system before birth. Since w e try to elu cid ate su bject exp eriences related to color, w e m u st clearly d isclose ou r m etap hysics. So, finally, the m etap hysical fram ew ork is the extend ed version of d u al-asp ect m onism that has the least nu m ber of p roblem s. This is called the DAMv fram ew ork: the Du al-Asp ect Monism w ith d u al-m od e and varying d egrees of the d om inance of asp ects d ep end ing on th e levels of entities, w here each entity has inseparable m ental and p hysical asp ects (Vim al, 2008, 2010a, 2012; Bru zzo & Vim al, 2007). This is better than the d om inant view , m aterialism , in science.

2. HYPERCOLUMN ID EA The cortical colu m n notion as a fu nctional u nit for m onkey som atosensory cortex w as first su ggested by Mou ntcastle and co-w orkers (Mou ntcastle, 1957; Pow ell & Mou ntcastle, 1959). Soon after ocu lar d om inance colu m n (eye-selective cells) concep t w as p rop osed by H u bel and Wiesel (1962) based on record ings from cells in p rim ary visu al cor tex of anesthetized cats and m onkeys (H u bel & Wiesel, 1962, 1974, 1977). H u bel and Wiesel also p rop osed that the colu m ns can be assem bled into larger u nits (i.e. hyp ercolu m ns constru cted by ad jacent ocu lar d om inance colu m ns) that inclu d e rep resentation of all fu nctions (a ll orientations and both eyes) w ithin each area of retinotop ic sp ace (H u bel & Wiesel, 1974, 1977). The p rop osed w id th of a hyp ercolu m n is 1–2 m m . A hyp ercolu m n contains a clu ster of neu rons that resp ond to the sam e retinal location, bu t w ith d ifferent orientation p references (H orton & Ad am s, 2005 Lu & Roe, 2008). That is, hyp ercolu m ns contains three su bsystem s as ocu lar -d om inance colu m ns, iso-orientation d om ains, and blobs. The ocu lar-d om inance colu m n is the segregation of inp u ts from the right and the left eye. These segregated inp u ts form the ocu lar -d om inance colu m ns, w hich ru n alm ost p arallel to one another in slabs. In the iso -orientation d om ains (or orientation p reference band s), each d om ain containing cells resp ond best to a given stim u lu s orientation. The sam e hyp ercolu m n also inclu d es the rep resentation of all orientations. The third su bsystem inclu d es neu rons that are selective for other attribu tes of the visu al stim u lu s, su ch as color and sp atial frequ ency. Thu s, a hyp ercolu m n contains the rep resentations of all attribu tes of a stim u lu s w ithin each area of retinotop ic sp ace (recep tive field ). These neu ronal cells are p laced in the m itochond rial cytochrom e oxid ase-rich blobs.

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Althou gh hyp ercolu m n id ea su ggested by H u bel and Wiesel can be an attractive notion, to d ate, there are d isagreem ents abou t the existence of hyp ercolu m ns. The visu al cortex (like other p arts of the cortex) is a continu ou s sheet and w e cannot find a stru ctu re that corresp ond s to the bord ers betw een the hyp ercolu m ns. H u bel m entions in his N obel Prize Lectu re that the hyp ercolu m ns bord ers are arbitrary, bu t it d id n‘t seem to w orry him . In a recent review by Lu nd et al. (2003) states that there is no fixed bou nd ary to su ch hyp ercolu m ns as there is a continu ou s change in p rop erty and m ean visu al field p o sition across the cortex. In ad d ition, as p er (H orton & Ad am s, 2005), ―Althou gh the colu m n has been offered as the fu nd am ental u nit of the cortex, it has not earned this lofty d esignation. After half a centu ry, it is still u nclear w hat p recisely is m eant by the term . It d oes not corresp ond to any single stru ctu re w ithin the cortex. It has been im p ossible to find a canonical m icrocircu it that corresp ond s to the cortical colu m n‖.

3. MITOCHON D RIAL CYTOCHROME OXID ASE-RICH BLOBS AN D COLOR REPRESEN TATION In p rim ates, the m ajor p athw ay serving visu al p ercep tion ru ns from the retina via the lateral genicu late nu cleu s (LGN ) to V1, V2, to extra striate areas and d istribu tion to higher cortical regions. From V1, m ost signals are conveyed to the V2 area before d istribu tion to higher cortical areas. Du ring visu al p ercep tion and im agery, the high activity of cytochrom e oxid ase (CO) is associated w ith high m itochond rial activity. CO is the last enzym e in the m itochond rial electron transp ort chain. The strict cou p ling betw een neu ronal activity and oxid ative energy m etabolism is the basis for the u se of CO as an end ogenou s m etabolic m arker for neu rons (Wong-Riley, 1989). Becau se CO staining intensity correlates w ith neu ronal fu nctional activity, w hen w e talk abou t CO activity w e also talk abou t m itochond rial activity. N am ely, CO activity can have d irect link w ith m itochond rial activity, d istribu tions, and p rocesses (as in neu ronal activity) (Bókkon & Vim al, 2010). Althou gh the d istribu tion of m itochond rial CO p rovid ed a p ersu asive exam p le of colu m nar stru ctu re in the V1, there are contrad ictions abou t the existence of hyp ercolu m ns. In ad d ition, a nonlinear d istribu tion of m itochond rial-rich CO blobs, w ith increased enzym e activity, can be id entified in the V1. These blobs ca n also be revealed by d iverse labeling techniqu es su ch as increased exp ression of N -m ethyl-D-asp artate (N MDA) or -am ino-5hyd roxy-3-m ethyl-4-isoxazole p rop ionic acid (AMPA) recep tors, and increased activity glu tam ate or ATPase, am ong others (Card er & H end ry, 1994; Card er, 1997; Wong-Riley, And erson, Liebl, & H u ang, 1998). Besid es, CO blobs ap p ear to be com m on to all p rim ates (Preu ss & Kaas, 1996). In ad d ition, blobs and interblob are fou nd not only in trichrom atic or d ichrom atic p rim ates bu t also in noctu rnal p rim ates w ith single fu nctional typ e of cone w ithin the retina (Wikler & Rakic, 1990). The fu nctional CO blobs in the su p ragranu lar layers extend to layer 6, w ith the excep tion of layer 4C (Takahata, H igo, Kaas, & Yam am ori, 2009). N eu rons in the V1 blobs have low orientation selectivity bu t resp ond to color and have higher firing rates com p ared to su rrou nd ing regions (interblobs) (Lu & Roe, 2008; Econom id es, Sincich, Ad am s, & H orton, 2011). In V1, layers 2 and 3 are com p osed of CO-d ense blobs and su rrou nd ing regions (interblobs) (Xiao & Fellem an, 2004). V2 is com p osed of alternating thin and thick CO -rich strip es and the p ale interstrip e regions betw een them . Accord ing to Sincich et al. (2007), d ifferent CO com p artm ents in V1 and V2 are connected in p arallel and the p rojection from V1 CO blobs to V2 CO thin strip es is resp onsible for color. In ad d ition, V1 and V2 can rep resent all the p rincip al su bm od alities of vision su ch as color, form , m otion, and d ep th (Bartels & Zeki, 1998). In the latest exp erim ents by Econom id es, Sincich, Ad am s, and H orton, p u blished in N atu re N eu roscience (2011), confirm ed p reviou sly p resented notion by Sincich and H orton

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(2005) that the visu al attribu tes of color, form , and m otion are not really segregated in V1. Accord ing to Econom id es et al. (2011), V1 contains local clu ster of neu rons jointly sensitive to orientation and color, p erhap s corresp ond ing to cytochrom e oxid ase blobs. Econom id es et al. (2011) also m ention: ―The abu nd ant concentration of cytochrom e oxid ase in p atches or blobs of p rim ate striate cortex has never been exp lained ‖. It is lesser-know n that the highest d ensity of neu rons in neocortex (nu m ber of neu rons p er d egree of visu al angle) (Rockel, H oirns, & Pow ell, 1980; O‘Ku sky & Colonnier, 1982) d evoted to rep resenting the visu al field are fou nd in V1. H ow ever, it is hard ly accid ental that the highest m itochond rial (energetic) activity can be achieved in V1 w ith m ito chond rial CO-rich regions in the brain. N am ely, V1 has the highest energy allocation for the visu al rep resentation and im agery in the brain, and m itochond rial-rich CO blobs m ay rep resent m onocu lar sites of color p rocessing. All things that exist in the natu re and u niverse have (d ynam ic) form (Pereira, 2012). If the (d ynam ic) form is the qu intessence of ou r w orld it m ay su p p ort that visu al inform ation via reflected visible p hotons (400-700 nm ) from objects/ form s m ight p lay the key role in visu al p ercep tion/ rep resentation and im agery. Ed w ald H ering (a Germ an p hysiologist (1834-1918) w ho p rop osed op p onent color theory in 1892) noted in the last centu ry that colors are alw ays sp atial. ―Ou r visu al w orld consists solely of d ifferently form ed colors […] seen objects, are nothing other than colors of d ifferent kind s and form s ‖ (H ering, 1874).

4. V1 MAY GUARAN TEE THE FIN EST AN D D ETAILED VISUAL REPRESEN TATION Du ring critical p eriod , both visu al stim u lation and intact visu al regions are necessary for norm al d evelop m ent of visu al fu nctions and im agery. Althou gh there are contrad ictions abou t if m ental im ages and p erceived stim u li are rep resented sim ilarly as w ell as if V1 is activated d u ring visu al im agery, recent exp erim ents su p p ort that V1 can be activated d u ring these states in healthy su bjects (Chen et al., 1998; Borst & Kosslyn, 2008; Klein et al., 2004; Cichy, H einzle, & H aynes, 2012). Ou r p resented n otions in this p ap er are related to intact V1 of healthy p ersons and not to the excep tional su bjects w ith d iverse V1 d am ages, lesions, and m alfu nctions. N evertheless, in excep tional V1 cases (d am ages, lesions), for exam p le, as it w as revealed in blind sight p henom enon, there are fu rther p ossible m echanism s byp assing or help ing V1 su ch as com p ensation, neu ral reorganization, p reserved ―island s‖ in V1 (genicu lostriate visu al p athw ay), p rojections to the su p erior collicu lu s and p u lvinar that can p rovid e ind irec t visu al inp u t to the extrastriate areas (retinotectal visu al p athw ay) (Fend rich, Wessinger, & Gazzaniga, 1992; Ptito & Leh, 2007), and at p resent still u nknow n V1 byp assing visu al netw orks. Recently, Boyer et al. (2005) d em onstrated that TMS ind u ces blind sight in a norm al p op u lation via an alternate genicu loextrastriate visu al p athw ay that byp asses V1, w hich can p rocess orientation and color w ithou t consciou s aw areness. Accord ing to Ganis et al. (2003), ―Many sorts of d eficits in im agery follow brain d am age, bu t the relation betw een the site of d am age and the typ e of d eficit is not sim p le or straightforw ard . The d issociations in p erform ance after brain d am age p rovid e hints regard ing the p rocessing system u nd erlying im agery, bu t d ifficu lties in interp retation u rge cau tion in m ap p ing these find ings to theoretic m od els. N eu roim aging techniqu es, su ch as PET and fMRI, op en a w ind ow into the w orking brain and offer valu able inform ation not easily accessible throu gh the stu d y of p atients, w ho, as noted , m ay have d eficits beyond those observable and m ay rely on com p ensation and neu ral reorganization ”. Lately, Ffytche and Zeki (2012) rep orted visu al aw areness in blind field s of three p atients w ith hem ianop ic field d efects. Au thors conclu d ed that ―the p rim ary visu al cortex or back p rojections to it are not necessary for visu al aw areness‖, how ever, they also acknow led ged that the blind field exp eriences of all three su bjects w ere d egrad ed and cru d e. If V1 striate cortex can be totally d am aged , the p rocesses that w ou ld take p lace there w ou ld then take p lace in the next available V2 visu al area. The V2 areas are also w ell

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retinotop ically organized (Cavu soglu , Bartels, Yesilyu rt, & Ulu d ağ, 2012) and p reserve the local sp atial geom etry of the retina (sim ilarly to V1), so p atterns of activation in V2 can d ep ict shap e (Kosslyn, 1994). There are nu m erou s fu rther visu al areas beyond V1 and V2 in w hat is know n as the p restriate cortex, and they have larger recep tive field s and cru d er top ograp hic organizations. V1 and V2 have com p arable su rface areas in the brain (Sincich, Jocson, & H orton, 2007). A m ap of V2 ap p roxim ates a m irror im age of the V1 (Zeki, 1977). V1 send s m ost of its cortical ou tp u t to V2 and in retu rn receives a strong feed back p rojection. There are ap p roxim ately 11,000 feed back neu rons in V2 and 14,000 feed forw ard neu rons in V1 (Rockland , 1997). There are esp ecially rap id feed forw ard and feed back p rocesses betw een V1 and V2 w ith cond u ction velocities arou nd 3.5 m / s (Girard , H u p é, & Bu llier, 2001). Accord ing to Sincich and H orton‘s (2005), ―… along w ith p hysiological and im aging stu d ies, now m ake it likely that the visu al at tribu tes of color, form , and m otion are not neatly segregated by V1 into d ifferent strip e com p artm ents in V2. Instead , there are ju st tw o m ain stream s, originating from cytochrom e oxid ase p atches and interp atches, that p roject to V2‖ . It su ggests that V2 cou ld rep resent the p rincip al su bm od alities of vision su ch as colou r, form , m otion and d ep th. Thu s, w hen V1 can be d am aged , V2 m ay be available to take u p V1 roles and p rod u ce sim ilar effective visu al im agery than V1 shou ld d o. Accord ing to latest transcranial m agnetic stim u lation (TMS) exp erim ents (Salm inenVap aranta et al., 2012) hu m an visu al aw areness cannot be generated w ithou t an intact V2. It m ay su p p ort ou r above m entioned notion that w hen striate cortex is d am aged , V2 m ay be able to take u p V1 roles and p rod u ce sim ilar effective visu al im agery than V1 shou ld d o. It is also p ossible that intact V1 m ay gu arantee the finest visu al p ercep tion and visu al im agery, bu t it is d ifficu lt to observe d u e to the su bjective rep orts of visu al exp erim ents and to the significant ind ivid u al stru ctu ral variability betw een norm al visu al system s of su bjects. 2 For exam p le, the m ean V1 su rface area is 2643 m m in hu m an, bu t the su rface range is 2 betw een 1986–3477 m m (Ad am s, Sincich, & H orton, 2007). Is it p ossible that the size of V1 (i.e. the nu m ber and size of fu nctional cells in V1) area can have som e influ ence on the visu al p ercep tion and im agination? Accord ing to Cattaneo, Bona, and Silvanto (2012), it is p ossible that fine d etails of im agery for w hich the sm all recep tive field s of V1 are su ited requ ires the p rim ary visu al cortex, althou gh w hen fin e d etails are not necessary, extrastriate regions are enou gh for im agery. It is a sim p le bu t im p ortant qu estion, w ou ld size of m itochond ria p op u lation be correlated w ith rep orts of p hosp henes and im agery and vivid ness and ind ivid u al d ifferences in these p henom ena? This w ou ld be an im p ortant exp erim ent to d o in the fu tu re. Energetic p rocesses can have essential role of V1 rep resentation m echanism s. Recent exp erim ents su ggest (Basole, White, & Fitzp atrick, 2003 Basole, Kreft-Kerekes, White, & Fitzp atrick, 2006) that p op u lation activity ((i.e. com binations of d ifferent stim u lu s featu res su ch as orientation, d irection, sp atial frequ ency) in V1 can be better revealed by a single m ap of sp atiotem p oral energy rather than m u ltip le m ap s of d ifferent stim u lu s featu res. Recently, w e p ointed ou t that sp atiotem p oral m itochond rial netw orks and p rocesses can also reflect rep resented inform ation w ithin neu rons d u ring sensory exp eriences (Bókkon & Vim al, 2010). N am ely, w hile the brain p rocesses inform ation from d ifferent p ercep tions, the energetic m echanism s (dynamic mitochondria networks and processes activated neurons) have to reflect the p erceived inform ation p rocesses becau se the energy d em and of neu ronal electrical activity is realized fu nd am entally by m itochond rial p rocesses. Since sensory inform ation p rocesses are d irectly linked to m itochond rial energetic p rocesses, it m eans that inform ation that com es from the d ifferent p ercep tions have to be rep resented not only by stru ctu ral p rocesses ( such as neural networks) and neu ronal electrical activity, bu t also by sp atiotem p oral energetic p rocesses of m itochond rial netw orks w ithin neu rons.

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5. CLUSTERS OF CO-RICH BLOBS AS POSSIBLE FUN CTION AL UN ITS FOR CON SCIOUS PHOSPHEN E PERCEPTION Phosp hene light p ercep tions can be p rod u ced in the visu al hem ifield contra -lateral to the stim u lated cortical hem isp here and reflect the retinotop ic organization of the visu al cortex (Brind ley & Lew in, 1968). TMS ind u ced p hosp henes can be p erceived regard less of w het her su bjects' eyes are op ened or closed . In ad d ition, p hosp henes are only p erceived by blind p atients that have p rior visu al exp erience, su ggesting that early visu al stim u lu s is essential to m aintain any level of resid u al visu al fu nction (Merabet, Theoret, & Pascu al-Leone, 2003). Visu al im agery can low er p hosp hene threshold (PT) (Sp aring et al., 2002) su ggesting that visu al im agery and intrinsic p hosp hene p ercep tion can be in d irect fu nctional relationship . The characteristics of p hosp henes are related to the fu nction and recep tive field organization of the stim u lated neu rons. Phosp henes ind u ced in V1, V2, and V3 visu al areas u su ally are stationary sm all blob-like form s (w ed ges, crescents, ellip ses) (Kam m er, 1999). Ind u ced p hosp henes in V4 and V5/ MT+ visu al regions u su ally are larger and p resent a ru d er retinotop ic stru ctu re, and even ad op t qu alities su ch as color, m otion or textu re (Marg & Ru d iak, 1994; Cow ey & Walsh, 2000). The CO blobs form nonlinear rep eating fu nctional u nits in V1. Accord ing to Tehovnik and Slocu m , (2007), ―The fu nctional u nit for p hosp hene ind u ction in V1 is m ost likely the hyp ercolu m n, w hich is abou t 1 x 0.7 m m of tissu e com p osed of layers sp anning som e 2 m m of tissu e from the su rface of cortex.‖ The sizes of CO blobs in m onkeys are abou t 514 m in the neonate enu cleated and 560 m in norm al anim als (Ku ljis & Rakic, 1990; Kenned y, Dehay, & H orsbu rgh, 1990). Ku ljis and Rakic (1990) fou nd that the center-to-center sp acing of blobs is 590 m in norm al and 598 m 2 in strabism ic m acaqu es. In ad d ition, the m ean d ensity of blobs w as 3.67 blobs/ m m in norm al 2 and 3.45 blobs/ m m in strabism ic m acaqu es. Besid es, CO blobs can d evelop in the absence of external visu al cu es from p hotorecep tors, and the CO layou t of the visu al cortex is not m od ifiable by visu al exp eriences (Ku ljis & Rakic, 1990). If w e com p are Tehovnik and Slocu m su ggestion that the fu nctional u nit for p hosp hene ind u ction is abou t 1 x 0.7 m m of tissu e w ith (Kenned y, Dehay, & H orsbu rgh, 1990; Ku ljis & Rakic, 1990) exp erim ental resu lts that the size of blobs 514-560 m or 590 - 598 m in anim als, it m ay su ggest that is m ore reasonable if the fu nctional u nit for p hosp hene ind u ction can be 2 linked to sm all clu sters (3-4 blobs/ m m ) of CO blobs and not d efinitely to the d ou btfu l and u np roved hyp ercolu m ns stru ctu re. One m ay argu e that w hy consciou s p hosp hene p ercep tion shou ld be linked to sm all clu sters of CO blobs, becau se p hosp henes can be elicited not only in CO -rich V1 area bu t also in V2, V3, V4, V5/ MT+, intrap arietal su lcu s (IPS) regions am ong them . First, the existence of hyp ercolu m ns is d ou btfu l w hile rep eating nonlinear u nits CO blobs in V1 has been p resented by m any exp erim ents (Lu & Roe, 2008, N akagam a & Tanaka, 2004 Mu rp hy et al, 1998). Second , recent exp erim ents (Fried et al., 2011; Taylor, Walsh, & Eim er, 2010) su ggest that all p hosp henes (that can be ind u ced in variou s regions (su ch as V2, V3 V4 or V5/ MT+, IPS am ong others) are d u e to the ind u ced activity of local circu its (local p rocesses contribu ting to p hosp hene generation are ind ep end ent) bu t feed -forw ard visu al inp u t from excited local circu its to V1 areas are necessary to p hosp hene aw areness. In ad d ition, since w e can interp ret the form , color and m ovem ent of ind u ced p hosp henes, it su ggests that not only feed -forw ard visu al inp u t from excited local circu its to V1 are necessary to p hosp hene aw areness bu t also feed back signals from higher level association areas. Since, as w as m entioned , V1 has the highest energy allocation for the visu al rep resentation and im agery; it su ggests that V1 m itoch ond rial CO-rich blobs can have esp ecially high role in the energy allocation for the visu al rep resentation and im agery. Accord ing to Taylor, Walsh and Eim er (2010), „While the ‗‗early‘‘ hyp othesis su ggests that p hosp hene related p otentials after occip ital TMS are fu nctionally analogou s to m otor -evoked p otentials follow ing M1 (p rim ary m otor cortex) TMS, the ‗‗late‘‘ hyp othesis claim s that consciou s p hosp hene p ercep tion and its associated p hosp hene-related p otentials are sim ilar 20


to the consciou s p ercep tion of external visu al stim u li and its electrop hysiological correlates‖. It su ggests that the p rocessing of p hosp hene p ercep tion is very sim ilar to m od el of the reverse hierarchy vision (Ahissar & H ochstein, 1997; H ochstein & Ahissar, 2002). Accord ing to reverse hierarchy hyp othesis (H ochstein & Ahissar, 2002), …„ou r initial consciou s p ercep t—vision at a glance— m atches a high-level, generalized , categorical scene interp retation, id entifying ―forest before trees.‖ For later vision with scrutiny, reverse hierarchy rou tines focu s attention to sp ecific, active, low -level u nits, incorp orating into consciou s p ercep tion d etailed inform ation available there. Reverse H ierarchy Theory d issociates betw een early exp licit p ercep tion and im p licit low -level vision, exp laining a variety of p henom ena‖. H ow ever, this hyp othesis can su p p ort that visu al ap p ercep tion has the highest energy allocation as w e also elu cid ated in ou r p reviou sly p ap er (Bókkon & Vim al, 2010). This extra energy allocation of exp licit p ercep tion m ight serve the d etailed (holistic (H ochstein et al., 2004) rep resentation of d etected visu al inform ation in V1 (d eterm ines w hether that inform ation reaches aw areness (Silvanto, Cow ey, Lavie, & Walsh, 2005). One of the m ost im p ortant qu estions in neu roscience is ―The Bind ing Problem ‖. N am ely, how encod ed item s can be com bined for coherent p ercep tion, d ecision, and action by d istinct brain regions. Du ring object p ercep tion, sep arated visu al featu res m u st be correctly integrated . Accord ing to featu re integration assu m p tion (Treism an, 1996), visu al stim u lation activates featu re d etectors in striate and extrastriate regions that link au tom atically to the object nod es in the tem p oral lobe. Latest stu d ies su p p ort that reentrant p rocessing betw een higher areas and early (V1) visu al cortex is critical factor for visu al bind ing and necessary for consciou s (and u nconsciou s) visu al p ercep tion (Koivisto, Mäntylä, & Silvanto, 2010; Koivisto & Silvanto, 2012). It m ay also su p p ort the notion that early (V1) v isu al cortex is critical for consciou s visu al p ercep tion as w ell as for consciou s p hosp hene p ercep tion.

6. PSYCHOPHYSICS AN D N EUROPHYSIOLOGY OF COLOR VISION Trichom ats have 3 p sychop hysical visu al channels (Kaiser & Boynton, 1996): Lu m inance/ Achrom atic channel, Red -Green color channel, and Yellow -Blu e color channel. Achrom atic and chrom atic p ercep tions and rep resentations are p rocessed by the lu m inance/ achrom atic channel and the tw o chrom atic channels (Red -Green color channel, and Yellow -Blu e color channel), resp ectively. Each has a nu m ber of tu ned m echanism s in orientation (Vim al, 1997), sp atial frequ ency (Vim al, 1998a, 1998b, 2002b), tem p oral frequ ency (Metha & Mu llen, 1996, 1997; Vim al, Pand ey & McCagg, 1995), and sp ectral/ color tu ning (De Valois & Jacobs, 1984; Engel, Zhang, & Wand ell, 1997). As p er (Vim al, 2011a), ―A psychophysical entity is an abstract m athem atical constru ct d erived by m od eling the exp erim ental d ata related to p sychop hysics and neu rop hysiology. For exam p le, there are 3 p sychop hysical visu al (card inal (Krau skop f, William s, & H eeley, 1982)) channels (su ch as the Red -Green, the Yellow -Blu e, and the achrom atic or lu m inance channels) d erived from p sychop hysical and p hysiological d ata (H u rvich & Jam eson, 1957; Kaiser & Boynton 1996; Krau skop f, William s, & H eeley, 1982). [...] The genu ine first-p erson m easu rem ents lead to the su bjective exp erience of color qu alia su ch as redness to greenness (see also (Dennett, 2003)). The third -p erson m easu rem ents w ill reveal the p hysical attribu tes su ch as neu ral activities in related neu ral-netw ork that inclu d es visu al red -green (R-G) color area ‗V4/ V8/ VO‘. In ad d ition, the exp erience of hu e, satu ration and brightness (first -p erson d ata) (Vim al et al, 1987) correlates w ith the activity of its neu ral-netw ork and the p rop erties of associated color stim u li (third -p erson d ata) (Bartels & Zeki, 2000; H ad jikhani et al, 1998; Kaiser & Boynton, 1996; Krau skop f et al, 1982; Tootell, Tsao, & Vand u ffel, 2003; Vim al, 1998b, 2002b; Wand ell, 1999). This psychophysical entity (su ch as the R-G channel) p rovid es a link betw een firstp erson d ata (phenomenal or mental aspect, su ch as redness to greenness) and third -p erson d ata (physical aspect, su ch as ‗V4/ V8/ VO R-G color neu ral-netw ork‘). Su bjective exp eriences (SEs) redness to greenness and ‗V4/ V8/ VO R-G color neu ral-netw ork‘ are cau sally related via the Red -Green channel. That is, active ‗V4/ V8/ VO R-G color neu ral-netw ork‘ cau ses SEs redness

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to greenness u p on the p resentation of equ ilu m inant red -green p atterns via the sp atial frequ ency (SF) tu ned m echanism s of the Red -Green channel (Vim al, 1998b, 2002b); these are external stim u lu s d riven SEs. Su bjective exp erience of color can also occu r by internal activation, su ch as electrical stim u lation, transcranial m agnetic stim u lation (TMS), and ‗m ed itation-ind u ced cortical p hosp henes w ith eyes closed ‘ (Vim al & Pand ey-Vim al, 2007). […] The color-contrast-constancy is p artly achieved at high contrasts and the inform ation p rocessing at su p rathreshold levels is d ifferent from that at the threshold levels (Vim al, 2000). Color and lu m inance SF d iscrim ination threshold s have a d ifferent SF d ep end ence; w hile color ap p ears to p erform better than lu m inance vision at low SFs, this effect is lost or even reversed at high SFs; color and form interact, bu t color and m otion are largely s egregated (i.e. they w eakly interact) (Vim al, 2002a).‖

7. COLOR AS SUBJECTIVE VISUAL EXPERIEN CE It is w ell-know n that hu m ans have three d ifferent typ es of cones in their eyes that p erceive the blu e, green, and red visible p hotons reflecting from objects. H u m an cones p igm ents have sp ectral p eaks of abou t 445 nm , 535 nm , and 570 nm (H u nt, Carvalho, Cow ing, & Davies, 2009). The color vision of d ogs is d ichrom atic and they have only tw o typ es of light -catching cone p hotorecep tor p igm ents. These tw o typ es of p igm ents have sp ectral p eaks of abou t 429 nm and 555 nm (N eitz, Geist, & Jacobs, 1989). Dogs cannot see red , orange or green colors bu t red , orange and green ap p ear as yellow or blu e to them . N am ely, d ogs can see yellow , blu e, and grey colors. Several typ es of bird s have a fou rth typ e of retinal cone p hotorecep tor cells (tetrachrom atic UV (Ultraviolet), 300 nm ), so their vision is m ore refined as com p ared to hu m an color vision. When w e can see a red ap p le at the sam e tim e, d ogs can see this ap p le w ith yellow -like color. So the qu estion can em erge, this ap p le in Figu re 1 is red or yellow -like. A d og‘s su bjective visu al exp erience can be that this ap p le is yellow -like bu t a hu m an‘s su bjective visu al exp erience is red . The correct d efinition cou ld be that this ap p le u nd er norm al p hotop ic circu m stances for p eop le w ith intact vision m akes a red visu al sense. So a color is not a p hysical featu re of an given object bu t a su bjective visu al exp erience that is d ep end on the long w avelength sensitive (LWS or red ) cone, m id d le w avelength sensitive (MWS or green) cone, and short w avelength sensitive (SWS or blu e) cone/ p ho torecep tor and visu al p rocesses and also on the context of ap p le.

Figure 1. A red ap p le. When w e can see a red ap p le at the sam e tim e, d ogs can see this ap p le w ith yellow -like color. (See the related thou ghts in the text.)

8. ACHROMATIC AN D CHROMATIC VISION Electrom agnetic light w aves (p hotons) visible to the hu m an eye range from abou t 400 to 700 nm . Attribu tes of visible p hotons/ light, su ch as w avelength and intensity, are p hysics; bu t 22


color and its attribu tes (su ch as hu e, satu ration, and brightness (Vim al et al, 1987)) are su bjective exp eriences, w hich are the m ental asp ect of colo r-related -neu ral-netw ork-state (Vim al, 2008, 2010a, 2012). A hu e is a p u re color, i.e. one w ith no black or w hite in it. In ou r p reviou s p ap er (Bókkon et al, 2011), w e elaborated that the w hite light (visible electrom agnetic p hotons) is a m ixtu re of all colors. Black or w hite, it's not an all or nothing case in everyd ay life. White objects are w hite becau se the m ost of the light that falls on th em is reflected by the m aterial. Black objects absorb light of all frequ encies bu t a little light (electrom agnetic p hotons) is reflected from them . Thu s, black is also a m ixtu re of all colors! White and black have the sam e hu e and satu ration, and the light ness is all that is d ifferent. The sensation of black is not the sam e as absence of light is one of the central tenets of H ering‘s teaching (H ering, 1874).

A

B

Figure 2. The sam e p hoto by colors (A) and by black (grey) and w hite (B).

When you can see the p hoto in Figu re 2a u nd er p hotop ic level, you say that is a color p hoto that is you r su bjective exp erience (SE) abou t this p hoto d u e to the reflected m ixtu re of visible ―color‖ p hotons (m ixtu re of electrom agnetic p hotons visible to the hu m an eye range from abou t 400 to 700 nm w avelength). When you can see the sam e p hoto in Figu re 2b u nd er p hotop ic level, you say that is a black and w hite p hoto. H ow ever, this is also you r su bjective exp erience abou t this p h oto bu t you r blackness and w hiteness su bjective exp eriences abou t the p hoto of Figu re 2b are also d u e to the reflected m ixtu re of visible ―color‖ p hotons (m ixtu re of electrom agnetic p hotons visible to the hu m an eye range from abou t 400 to 700 nm w avelength s). In the hu m an retina there are rod s and three typ es of cones p hotorecep tors, each of w hich absorbs d ifferent range w avelengths (Figu re 3) of external visible electrom agnetic p hotons (Brow n & Wald , 1964).

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Figu re 3. Photon absorp tion cu rve for R: rod is show n by black d otted cu rves., L: long w avelength sensitive cone by red cu rve, M: m id d le w avelength sensitive cone by green cu rve, and S: short w avelength sensitive cone by blu e cu rve.

We can read essentially in the m ost of scientific literatu res that rod s d o not d iscern colors like cones d o (i.e., rod vision is achrom atic night vision), althou gh they are highly sensitive to light, and u su ally the p hoton absorp tion cu rve for rod is show n by black d otted cu rves., long w avelength sensitive cone by red cu rve, m id d le w avelength sensitive cone by green cu rve, and short w avelength sensitive cone by blu e cu rve (see in Figu re 3). H ow ever, rod p hotorecep tors convey electrom agnetic visible p hotonic signals in the hu m an eye ranging from abou t 400 to 700 nm w avelength; sim ilarly for cones w ith lim ited range. Cones are for color vision, nevertheless, rod s also absorb sim ilar color p hotons as cones d o, and they also cou ld contribu te to su bjective color p ercep tion (Stabell & Stabell, 1994; Cao, Pokorny, Sm ith, & Zele, 2008) to certain extent, bu t not like d ay color vision via 3 cones. In other w ord s, bu t rod s convey electrom agnetic visible color m ixed p hotonic signals in the hu m an eye ranging from abou t 400 to 700 nm these p rod u ce su bjective black and w hite exp er ience in the brain. Althou gh vision science m akes p ractical d ifference betw een achrom atic and chrom atic vision, both are su bjective exp eriences are p rod u ced by m ixed visible color p hoton signals in the hu m an eye ranging from abou t 400 to 700 nm .

9. MOD AL AN D AMOD AL VISUAL COMPLETION Althou gh recent exp erim ents p rovid ed evid ence that visu al, au d itory, and som atosensory integrations take p lace p arallel at nu m erou s levels along brain p athw ays (Giard & Peronnet, 1999; Macalu so, Frith, & Driver, 2000; Calvert, Sp ence. & Stein, 2004) and in ou r everyd ay p ercep tion m ost objects and events can be seen, heard , and tou ched , i.e. these are p rim arily interm od al p ercep tion, i.e. inform ation from events or objects available to m u ltip le senses sim u ltaneou sly, for the u nd erstand ing of ou r thou ghts p resented here w e focu s to visu al p ercep tion per se. A m ajor challenge of vision research is to m ake it clear how the visu al system can com p lete m issing stru ctu res d u ring visu al p ercep tion. In ou r everyd ay aw areness of the su rrou nd ing w orld in alm ost all cases of visu al p ercep tion inclu d e one or m ore am od al p arts. In am od al com p letion, there is a com p letion of an object that is not com p letely visible becau se it is covered (occlu d ed , hid d en) by som e thing else (Kanizsa & Gerbino, 1982). In m od al com p letion p henom enon a shap e can be p erceived that is occlu d ing other shap es even w hen the shap e itself is not d raw n (Figu re 4). For exam p le the triangle that ap p ears to be occlu d ing three d isks in the Kanizsa triangle. Accord ing to (N anay, 2007), ―am od al p ercep tion relies heavily on ou r backgrou nd know led ge of how the occlu d ed p arts of the object (m ay) look. If I have never seen a cat, I w ill have d ifficu lties attribu ting p rop erties to its tail behind the fence‖. N anay states that 24


w hen w e rep resent featu res of p erceived objects that are not actu ally visible to u s, w e can u se m ental im agery. It is also tru e for visu al im agery. If w e w ant to visu alize an object w e m u st know how this look. In ad d ition, ou r ind ivid u al belief also can contribu te to the rep resentation of non -visible object featu res (Briscoe, 2011). Since d u ring am od al com p letion as w ell as d u ring m od al visu al com p letion w e can exp erience su ch p hysical featu res of an object that are not d u e to the external visible p hoton signals absorbed by retinal p hotorecep tors, it su p p orts that these p rocesses are achieved by intrinsic m echanism s betw een V1 and higher level areas. It seem s that am od al visu al com p letions are d u e to the visu al p ercep tion ind u ced visu alization p rocesses w hen ou r brain tries to interp ret the u nseen p arts of objects or in m od al visu al com p letions the brain rep resent featu res of p erceived objects that are not actu ally visible. These p rocesses essentially d ep end on ou r backgrou nd visu al k now led ge (and also ou r ind ivid u al belief), nam ely, essentially d ep end on stored long -term (visu al) m em ory. Thu s w e agree w ith N anay that am od al visu al p ercep tion can be a version of visu alization, i.e. visu alize the u nseen p arts of objects w e are looking a t. Recent exp erim ents by Mu rray et al. (2002, 2004) revealed that in hu m ans both m od al and am od al com p letion p rocesses share a com m on initial neu rop hysiological sp atiotem p oral m echanism , bu t w ith d ifferential p rocessing latencies. It is p ossible that feed forw ard visu al signals from V1 and V2 are sent to higher visu al areas that m od u late V1 and V2 resp onses to visu al stim u li, w hich finally can p rod u ce m od al com p letion or am od al com p letion (Albert, 2007; Mu rray et al., 2002, 2004). This m od u lation of V1 and V2 resp onses to external visu al stim u li essentially d ep end on stored long -term visu al m em ory (backgrou nd visu al know led ge). It is also p ossible that the com p letion of occlu d ed contou rs (filling -in) p henom ena are d ep end ent on the sp atial scale of the occlu sion; local p rocessing can accou nt for sm all gap s or occlu sions w hile larger gap s or occlu sions m ost likely d ep end on feed back signals arising from neu rons w ith significantly larger recep tive field s. One m ay argu e that w hat allow s u s to see is the p ercep tion of su rfaces and layou t, these are am od al featu res, can be w ithou t color at all and can be achieved throu gh su ggesting ed ges or contou rs, as in the p ow erfu l d em onstration of su bjective contou rs, geom etry/ form has very little to d o w ith color per se, su rface and ed ges are w hat show shap e to the visu al system . N evertheless, it is not tru e. As m entioned above, p hotorecep tors and variou s retinal cells p rocess and convey essentially external visible electrom agnetic (color) p hotonic inform ation to LGN and to V1 and other visu al areas that is m od u lated by ad d itional sensory m od alities d u ring m u ltisensory integration. It is p ossible that first step s of visu al p ercep tion (and rep resentation) are basically nothing other than rep resentation of external visible (color) electrom agnetic p hotons achieved in V1 CO-rich visu al areas. Du ring visu al p ercep tion, inform ation originated from su rfaces and ed ges is also d u e to the external visible (color) electrom agnetic p hotons. Du ring visu al m od al com p letion or am od al com p letion the first step s that d etected external (color) p hoton signals are ru n from the retina via the LGN to V1, V2 and then signals conveyed to extrastriate and to higher level visu al and association areas. N ext, feed back signals (d ep end s on ou r backgrou nd visu al know led ge originated from long term (visu al) m em ory and also on ou r ind ivid u al belief, Figu re 5) m od u late original d etected and rep resented object in retinotop ic V1, w hich finally m akes m od ified p ercep tion, i.e. m od al com p letion or am od al com p letion. This p rocess is also consistent w ith the reverse hierarchy theory of vision. Accord ing to recent electroencep halogram (EEG) and fu nctional m agnetic resonance im aging (fMRI) exp erim ents (Scholte, Jolij, Fahrenfort, & Lam m e, 2008), textu re bou nd aries are d etected in a feed forw ard m anner and are rep resented at increasing la tencies by higher visu al regions. In ad d ition, su rface segregation is rep resented by reverse hierarchical p rocesses that arise from feed back signals to early visu al areas su ch as V1.

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Figure 4. Mod al visu al com p letion. The triangle that ap p ears to be occlu d ing three d isks in the Kanizsa triangle.

Figure 5. Am od al visu al com p letion d ep end s on ou r backgrou nd visu al know led ge and also on ou r ind ivid u al belief. Ou r ind ivid u al belief cou ld su ggest that p artially covered u nseen p arts horse in A shou ld be com p leted by ou r visu al im agery to form an ord inary horse. Bu t as B ind icates it is a fem ale centau r. [Source: http:/ / en.w ikiped ia.org/ w iki/ File:GiorcesBardo55.jpg ]

10. SPATIAL VISUAL PERCEPTION AN D IMAGERY Som e researchers argu e that visu al and sp atial im agery can be rep resented d ifferently (Farah, H am m ond , Levine, & Calvanio, 1988; Vannu cci and Mazzoni 2009). N evertheless, accord ing to their recent fMRI stu d ies, Golom b and Kanw isher (2011) state, ―d esp ite ou r su bjective im p ression that visu al inform ation is sp atiotop ic, even in higher level visu al cortex, object location continu es to be rep resented in retinotop ic coord inates ”. In ad d ition, they su ggested that there is a not exp licit hard -w ired sp atiotop ic m ap in the brain and the sp atiotop ic object p osition can be com p u ted not d irectly and continu ally reconstru cted by each eye m ovem ent. It is p ossible that ou r cap acity for sp atial visu al p ercep tion and im agery are learned ability that p erform ed / com p u ted by higher level visu al and association areas (linked to other sensory m od alities), bu t first step s of visu al p ercep tion (and rep resentation) is essentially nothing other than p ercep tion (and rep resentation) of external visible electrom agnetic p hotons achieved basically in retinotop ic V1 m itochond rial-rich CO areas.

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11. POSSIBLE ROLE OF BIOLUMIN ESCEN T RETIN AL BIOPHOTON S IN THE D EVELOPMEN T OF RETIN OGEN ICULATE PATHWAYS AN D IN ITIAL APPEARAN CE TOPOGRAPHIC MAP FORMATION OF V1 AN D CO BLOBS BEFORE BIRTH Early visu al exp erience is fu nd am ental to shap e the m atu ration of cortical circu its and is also ind isp ensable to norm al color and visu al p ercep tion d u ring d evelop m ent (Su gita, 2004). Exp erim ents revealed that retinogenicu late p athw ays and CO blobs em erge before birth and visu al exp erience is not essential for the init ial ap p earance or early d evelop m ent of CO blobs in cats and m acaqu es, w hich su ggests that CO blobs cou ld reflect an innate and stru ctu ral organization of early visu al cortex (Ku ljis & Rakic, 1990; Mu rp hy, Du ffy, Jones, & Mitchell, 2001). Besid es, the CO layou t of the visu al cortex is not m od ifiable by visu al exp eriences (Mu rp hy, Du ffy, Jones, & Mitchell, 2001). It is generally believed that retinal w aves p lay a m ajor instru ctive role in the m atu ration of the visu al system . Du ring d evelop m ent of the visu al system , in the higher and low er vertebrates, ganglion cells in the im m atu re and light -insensitive retina sp ontaneou sly and synchronou sly creates end ogenou sly w aves (action p otentials) that are transm itted to the lateral genicu late nu cleu s (H u berm an, Feller, & Chap m an, 2008). Am acrine cells also p articip ate in the correlated activity p atterns. Sp ontaneou s retinal w aves are conveyed to t he visu al cortex and w here can trigger end ogenou s sp ind le bu rsts. Chalu p a (2009) p ointed ou t that retinal w aves are d ou btfu l to have su ch a role, and su ggested that eye-sp ecific m olecu lar cu es in com bination w ith neu ronal activity are p robably involved in the d evelop m ent of eye-sp ecific retinogenicu late p athw ays. N evertheless, several exp erim ents p roved (Kobayashi et al., 1999; Kataoka et al., 2001; N arici et al., 2009, 2012; Catalá, 2006; Ad am , Kazakov, & Kazakov, 2005; N akano, 2005) that natu ral lip id p eroxid ation is one of the m ain sou rces of sp ontaneou s u ltraw eak (bio)lu m inescent biop hotons. Und er regu lated circu m stances, lip id p eroxid ation i s a natu ral p rocess in cells and also in retinal m em branes. Since the natu ral lip id p eroxid ation is one of the m ain sou rces of biolu m inescent biop hotons and the p hotorecep tors have the highest oxygen d em and and p olyu nsatu rated fatty acid (PUFA) concentration in the bod y (N ielsen, Mau d e, H u ghes, 1986; You d im , Martin, & Josep h, 2000), there can be a p erm anent, low -level biolu m inescent biop hoton em ission w ithin the retina w ithou t any external light stim u lation in the retinal of fetu s in the u teru s. In ad d ition, recently w e (Wang, Bókkon, Dai & Antal, 2011) p resented the first exp erim ental evid ence of the existence of sp ontaneou s and visible light ind u ced (also called as d elayed lu m inescence) u ltraw eak biop hoton em ission from in vitro freshly isolated rat‘s w hole eye, lens, vitreou s hu m or and retina. Ou r resu lts su p p ort ou r p reviou sly p red ictions (Bókkon, 2008; Bókkon & Vim al, 2009) that retinal d iscrete d ark noise as w ell as retinal p hosp henes can be d u e to the natu ral biolu m inescent biop hotons originated w ithin the retinal system (Figu re 6). If w e consid er the above m entioned , it m ight su ggest that continu ou sly generated biolu m inescent biop hotons from retinal lip id p eroxid ation m ay also have fu nctional role in early d evelop m ent of retinogenicu late p athw ays and initial ap p earance top ograp hic organizations of V1 and CO blobs before birth, becau se retinal sp ontaneou s biop hotons can continu ou sly send intrinsic signals via p hototransd u ction cascad e to the V1 area that interp rets these retinal biop hotons as if they originated in the external visu al w orld .

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Figure 6. Biolu m inescent biop hotons from natu ral retinal lip id p eroxid ation ind icated by red jagged arrow s. It is p ossible that a given rod or cone em its a biolu m inescent biop hoton that changes its d irection, and su bsequ ently can absorb its ow n biolu m inescent p hoton. A rod or cone can absorb biolu m inescent biop hotons from the lip id p eroxid atio n of ad jacent rod s or cones.

12. METAPHYSICS Since w e are trying to exp lain su bject exp eriences related to color (su ch red ness), w e m u st clearly d isclose ou r m etap hysics. (Vim al, 2012) d iscu sses it as follow s: One cou ld categorize 1 all entities of ou r u niverse in tw o categories : physical (P: su ch as ferm ions, bosons and their com p osites inclu d ing classical inert entities and neu ral netw orks (N N s) in objective third p erson p ersp ective (3p p )) and mental entities (M: su ch as su bjective exp eriences, self, thou ghts, attention, intention, and other non -p hysical entities in su bjective first p erson p ersp ective (1p p )). This categorization entails 4 m ajor p hilosop hical p ositions: (i) M from P (P is p rim itive/ fu nd am ental; exp eriences em erge from the interactions of feed forw ard and feed back signals in neu ral-netw orks or id entical w ith brain -states): natu ralistic/ p hysicalistic/ m aterialistic nond u al m onism , p hysicalism , m at erialism , red u ctionism , non-red u ctive p hysicalism , natu ralism , or Cārvāka/Lokāyata (800-500 BCE (BCE = Before Com m on Era; BC = Before Christ; For exam p le 400 BC is 400 BCE)); (ii) P from M (M is p rim itive; m atter -in-itself is ‗congealed ‘ m ind ): id ealism , m entalistic nond u al m onism , or A dvaita (788-820 AD (AD = Anno Dom ini, referring to the year of Christ‘s birth));(iii) P and M are ind ep end ent bu t can interact w hen w e are alive (both P and M are equ ally p rim itive: interactive su bstance d u alism , Prakṛti and Puruṣa of Sāṃkhya (1000– 2 600 BCE or even before Gītā (3000 BCE) ; and (iv) P and M are tw o inseparable asp ects of a state of an entity (fu nd am ental entity, su ch as ferm ions and bosons, the ‗p rim itive‘ qu antu m

1

One could argue that categorizing the world into two categories, physical and mental, is the bases of psychophysics initiated by Fechner in the late 19th century and achieved the technical asymptote in Woodsworth and Schlosberg's Experimental Psychology text during the middle of the 20th century. 2 The Gītā is a 700-verse scripture that is part of the Hindu epic Mahābhārata. This scripture contains a conversation between Pāndava prince Arjuna and his guide Lord Krishna on a variety of theological and philosophical issues. 28


3

field / p otential : d u al-asp ect m onism , neu tralism , Kashmir Shaivism (860–925 CE (CE = Com m on Era, recent term )) and V iśiṣṭādvaita (1017-1137 CE: m ind (cit) and m atter (acit) are ad jectives of Brahman). The su bjective 1p p -m ental asp ects of the states of entities w ere fu rther investigated by Titchener (1867-1927) w ho p rop osed stru ctu ralism (influ enced from Wu nd t‘s theory of volu ntarism : ‗w ill‘ is su p erior to intellect and em otion and is the basic factor both in the u niverse and in hu m an cond u ct), w here the stru ctu re of exp erience w as stu d ied by u sing su bjective analytic introsp ection to d isclose the bu ild ing blocks of m ental entities. H e p rop osed three typ es of m ental elem ents constitu ting consciou s exp erience: Sensations (elem ents of p ercep tions: m ore than 44,000 d ifferent sensations), Im ages (elem ents o f id eas), and affections (elem ents of em otions). These elem ents cou ld be broken d ow n into their resp ective attribu tes: qu ality, intensity, d u ration, clearness, and extent (Sheehy, 2003, p p .224 226). The attribu te ‗qu ality‘ d ifferentiates sensations; the ‗intensity‘ and the ‗d u ration‘ attribu tes refer to ―the strength of an exp erience‖ and ―the p eriod an exp erience lasts‖, resp ectively; the ‗clearness‘ attribu te sp ecifies ―how m u ch an exp erience stand s ou t from its back grou nd ‖ and the ‗extent‘ attribu te refers to ―exp erience in term s of sp atial d im ension‖ (Sheehy, 2003, p .227). Both sensations and im ages contain all of these qu alities; how ever, affections lack in clearness and extensity/ extent; the id ea of associationism (the association of one m ental state w ith its su ccessor states for the op eration of m ental p rocesses) entails how the m ental elem ents com bined and interacted w ith each other to form consciou s exp erience; the law of contigu ity (things that occu r near each other in tim e or sp ace are read ily associated ) im p lies that ―the thou ght of som ething w ill tend to cau se thou ghts of things that 4 are u su ally exp erienced along w ith it‖. The objective 3p p -p hysical asp ects of the states of entities w ere fu rther investigated by Boring (1886-1968) w ho attem p ted to accom m od ate behaviorism by view ing sensations throu gh their 3p p -p hysical m echanism s from his m onist p hysicalism p ersp ective (Boring, & Gard ner, 1967); he focu sed on a p hysical brain rather than the abstract m ind . This view m ay seem in d irect op p osition to m entalist and d u alist p ersp ective of his m ento r Titchener, bu t it is com p lem entary in ou r view becau se 3p p -p hyscial and 1p p -m ental asp ects of a state of brain is inseparable in ou r extend ed d u al-asp ect m onism fram ew ork. The fram ew ork (i)-m aterialism is the d om inant view in science, and (ii)-id ealism and (iii)interactive-su bstance-d u alism are the d om inant view s in religions; all (i)-(iii) have seriou s p roblem s. The fram ew ork (iv)-DAM has the least nu m ber of p roblem s; the p rop osed DAMv fram ew ork is the extension/ m od ification of DAM (DAM = D u al-Asp ect Monism ): As p er (Vim al, 2011b), ―The DAMv fram ew ork consists of three essential com p onents: (1) the D u alAsp ect Monism (Vim al, 2008), w here each entity has inseparable m ental and p hysical asp ects; (2) d u al-m od e (Vim al, 2010a); and (3) varying d egrees of the d om inance of asp ects d ep end ing on the levels of entities (Vim al, 2012).‖ As p er (Vim al, 2012), ―The m ental asp ect is from the su bjective first p erson p ersp ective and the p hysical asp ect is from the objective third p erson p ersp ective. This fram ew ork is optimal becau se it has the least nu m ber of p roblem s (Vim al, 2010a).‖ Du al asp ect m onism in this interp retation w ou ld m ean that there is certain kind of reality that enables to p rod u ce m ental exp erience and its corresp ond ing p hysical level. Critiqu e can qu estion: Is there som ething w hich p resents ad vantage of this view for em p irical sciences? Yes, there is ind eed a great ad vantage on m ore realistic qu antu m p hysics based extend ed d u al-asp ect m onism (DAMv) m etap hysics com p ared to the obsolete classical p hysics based m aterialism . The DAMv fram ew ork (Vim al, 2008, 2010a, 2012) has the least nu m ber of p roblem s com p ared to all other typ es of m etap hysics (su ch as m aterialism , id ealism , and interactive su bstance d u alism ). The p roblem s are d iscu ssed in (Vim al, 2010b). Even neu roscientists Koch (2012) and Tononi (2004) have now changed their m etap hysical view 3

See ('t Hooft, 2005).p4 for ‗primitive‘ quantum field, (Bohm, 1990) for quantum potential, and (Hiley & Pylkkänen, 2005) for ―primitive mind-like quality at the quantum level via active information‖. 4 Adapted from . See also (Titchener, 1929).

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from m aterialism to d u al-asp ect m onism becau se this is closest to Fu nd am ental Tru th; this is su m m arized in (Vim al, 2012). The d om inant m etap hysics of science is m aterialism , w hich has p roblem s: As p er (Vim al 2010b), ―In [the id entity theory of] m aterialism , a sp ecific exp erience (SE: su ch as redness) is identical with a sp ecific state (su ch as the red ness-related state cau sed by long w avelength light) of a sp ecific neu ral-netw ork (su ch as red -green V4/ V8/ VO-neu ral-net) (Levin, 2006; Levin, 2008; Loar, 1990, 1997; Pap ineau , 2006). In [the em ergence or red u ction theory of m aterialism ...], qu alia/ su bjective exp eriences (su ch as redness) are assu m ed to m ysteriou sly em erge or red u ce to ... relevant states of neu ral-nets ... The m ajor p roblem is Levine‘s exp lanatory gap (Levine, 1983): the gap betw een exp eriences and scientific d escrip tions of those exp eriences (Vim al, 2008). In other w ord s, how can ou r exp eriences emerge (or arise) from non-exp eriential m atter su ch as the neu ral-netw orks of ou r brain or organism environm ent interactions? [...] Furtherm ore, m aterialism / em ergentism has 3 m ore assu m p tions (Skrbina, 2009): m atter is the u ltim ate reality, and m aterial reality is essentially objective and non-exp eriential. These assu m p tions need ju stification.‖ A sp ecific SE is the realization of related potential SE. Potential SEs are su p erp osed in the m ental asp ect of each entity-state in the DAMv fram ew ork (Vim al, 2008, 2010a, 2012). A sp ecific SE is realized by (i) satisfying the necessary ingred ients of consciou sness (Vim al 2011a) elaborated later, and (ii) m atching and selection m echanism s (Vim al, 2010a): (a) m atching/ interaction of stim u lu s-d ep end ent feed forw ard signals and cognitive feed back signals and (b) then selecting a sp ecific SE related to stim u lu s from the virtual reservoir, w hich is the storage area for the p otential SEs in su p erp osed form in the m ental asp ect of each entity-state (elaborated later). An entity cou ld be anything from qu antu m p article/ field to brain‘s neu ral-netw orks. A color stim u lu s is a reflected light (from abou t 400 to 700 nm w avelength) and / or m ixed visible p hotons of variou s w avelengths and intensit ies. These p hotons are absorbed in you r p hotorecep tors and p rocessed by retinal, LGN , and cortical neu rons of variou s visu al areas, sp ecifically color -related V4/ V8/ VO-neu ral netw ork (N N ) elaborated below . A brain‘s N N -state has insep arable m ental asp ect (su ch as SE red ness) and p hysical asp ect (su ch as color-related V4/ V8/ VO-N N and its activities).

13. CRITIQUES 13.1. Critique 1: The m anu scrip t is w ell articu lated and w ou ld m ake an excellent contribu tion to the literatu re on p hilosop hy of the m ind . There are tw o m inor issu es. First, you have not show n that su bjective visu al exp erience m u st be exclu d ed from m aterialism . Materialism is not sim p ly the stru ctu re of the neu ral netw orks, bu t also the d ynam ics d riven by the ionic com p osition and the electrical p atterns that can m anifest from the neu ral stru ctu re. Therefore, exp erience can em erge from non -exp eriential m atter su ch as neu ral netw orks d u e to d ynam ic continu ity. Second , you have not inclu d ed selectionism (neu ral Darw inism ) as a p rocess of su bjective exp erience. Finally throu ghou t the m anu scrip t there are nu m erou s statem ents and assertions w ithou t su p p orting evid ence. Therefore the m anu scrip t shou ld be revised so that assertions or hyp othesis are su p p orted by the literatu re; otherw ise it shou ld be m ad e clear that su ch are not yet scientifically p roven. Reply: (1) Exp eriences cannot em erge from non -exp eriential m atter by d efinition. An entity-state m u st have d u al-asp ect natu re. The hyp othesis of em ergence is still m ysteriou s bu t is ad d ressed to som e extent in (Vim al, 2010a) and (Vim al, 2012). The d ynam ics d riven by the ionic com p osition and the electrical p atterns that can m anifest from the neu ral stru ctu re is d iscu ssed in (Vim al, 2010a). (2) The selectionism (neu ral Darw inism ) as a p rocess of su bjective exp erience is d iscu ssed in (Vim al, 2010a) along w ith the m atching and selection of sp ecific exp erience. (3) The assertions or hyp othesis are not su p p orted by the literatu re are not yet scientifically p roven.

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14. SUMMARY Briefly su m m arized som e im p ortant thou ghts are show n below .  The hyp ercolu m n notion su ggested by H u bel and Wiesel m ay be attractive, bu t to d ate, there are d isagreem ents abou t the existence of hyp ercolu m ns.  Du ring visu al p ercep tion and im agery, the high activity of cytochrom e oxid ase (CO) is associated w ith high m itochond rial activity.  The strict cou p ling betw een neu ronal activity and oxid ative energy m etabolism is the basis for the u se of CO as an end ogenou s m etabolic m arker for neu rons.  V1 contains local clu ster of neu rons jointly sensitive to orientation and color, p erhap s corresp ond ing to CO blobs.  The highest d ensity of neu rons in neocortex (nu m ber of neu rons p er d egree of visu al angle) and the highest volu m e of gray m atter of the retino -genicu lostriate p athw ay d evoted to rep resen ting the visu al field are fou nd in V1.  It is p robable that the visu al attribu tes of color, form , and m otion are not neatly segregated by V1 into d ifferent strip e com p artm ents in V2.  The CO blobs form nonlinear rep eating fu nctional u nits in V1.  Feed -forw ard visu al inp u t from excited local circu its to V1 is necessary to p hosp hene aw areness.  Attribu tes of visible p hotons/ light, su ch as w avelength and intensity, are p hysics; bu t color and its attribu tes su ch as hu e, satu ration, and brightness are su bjective exp eriences.  Althou gh vision science m akes d ifference betw een achrom atic and chrom atic vision, both are su bjective exp eriences are p rod u ced by m ixed visible color p hoton signals in the hu m an eye ranging from abou t 400 to 700 nm .  Reentrant p rocessing betw een h igher areas and early (V1) visu al cortex is necessary for consciou s and u nconsciou s visu al p ercep tion as w ell as for p hosp hene p ercep tion. H ere w e argu ed that the visu al p ercep tion and rep resentation are essential based on p ercep tion and rep resentation of colors (colors as external visible electrom agnetic p hoton signals). This rep resentation is the m ost energetic allocation p roced u re in the brain, w hich is logically achieved by highest d ensity neu ronal V1 regions w ith m itochond rial -rich CO blobs. Of cou rse, p erceived and rep resented colors (as visible electrom agnetic p hotons) in V1 areas (and in CO blobs) are m od u lated by other sensory m od alities d u ring m u ltisensory integration and are interp reted by su p erior level p rocesses that finally p rod u ce su bjective visu al exp eriences. It w as su ggested that the fu nctional u nit for p hosp hene ind u ction can be linked to sm all 2 clu sters (3-4 blobs/ m m ) of CO blobs in V1 and not to the hyp ercolu m ns stru ctu res. Althou gh vision research m akes d ifference betw een achrom atic and chrom atic vision, both are su bjective color exp eriences p rod u ced by m ixed visible (color) p hoton signals in the hu m an eye ranging from abou t 400 to 700 nm . In ad d ition, w e p resented som e thou ghts related to the p hysics of visible p hotons/ light and its su b jective exp eriences. Du ring visu al m od al com p letion or am od al com p letion the first step s that d etected external (color) p hoton signals are ru n from the retina via the LGN to V1, V2 and then signals conveyed to extrastriate and to higher level visu al and association areas. Then, feed back signals (d ep end ing on ou r backgrou nd visu al know led ge originated from long term (visu al) m em ory and also on ou r ind ivid u al belief) m od u late original d etected and rep resented object in retinotop ic V1, w hich finally m akes m od ified p ercep tion, i. e. m od al com p letion or am od al com p letion. This p rocess is also consistent w ith the reverse hierarchy theory of vision.

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Becau se biolu m inescent biop hotons can continu ou sly send intrinsic signals to the V1 area that interp rets these retinal biop hotons as if they originated in the external visu al w orld , w e also raised that constantly p rod u ced biop hotons from retinal lip id p eroxid ation m ight also have fu nctional role in early d evelop m ent of retinogenicu late p athw ays as w ell as initial ap p earance top ograp hic organizations of V1 and CO blobs before birth, The link betw een stru ctu re (su ch as V4/ V8/ VO -N N ), fu nction (su ch as d etection and d iscrim ination of color), and su bjective exp eriences (su ch as red ness and greenness) w as exp lained best by the DAMv m etap hysical fram ew ork becau se it has the least nu m ber of p roblem s.

D ECLARATION OF IN TEREST The au thors rep ort no conflicts of interest. The au thors alone are resp onsible for the content.

ACKN OWLED GMEN TS We w ould like to acknow led ge Prof. Ed w ar d J. Tehovnik, Prof. Rom an Richard Poznanski, and anonym ous review ers for help ful com m ents on the m anuscript. Bókkon‘s URL: http:/ / bokkon-brainim agery.5m p.eu . The w ork w as partly supported by VP-Research Found ation Trust and Vision Research Institute research fund to RLPV. Author w ould like to thank anonym ous review ers, Manju Um a C. Pand ey-Vim al, Vivekanand Pand ey Vim al, Shalini Pand ey Vim al, and Love (Shyam ) Pand ey Vim al for their critical com m ents, suggestions, and gram m atical corrections. RLPV is also affiliated w ith Dristi Anusand hana Sansthana, A-60 Um ed Park, Sola Road , Ahm ed abad -61, Gujrat, Ind ia; Dristi Anusand hana Sansthana, c/ o N iceTech Com puter Ed ucation Institute, Pend ra, Bilaspur, C.G. 495119, Ind ia; and Dristi Anusand hana Sansthana, Sai N iw as, East of H anum an Mand ir, Betiahata, Gorakhpur, U.P. 273001, Ind ia. Correspond ing author‘s Em ail: [email protected] . RLPV‘s em ail ad d resses are rlpvim [email protected] and rlpvim al@gm ail.com ; URL: http:/ / sites.google.com / site/ rlpvim al/ H om e/ .

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