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Email: [email protected]. Received 9 May 2006; revised 26 March 2007; accepted 15 April. 2007. .... obtained using single-shot gradient-refocused echop- lanar imaging (TR 4000 ... weighted MRI template whose space can convert to the.
Psychiatry and Clinical Neurosciences (2007), 61, 355–363

doi:10.1111/j.1440-1819.2007.01687.x

Regular Article

Changes of brain activity in the neural substrates for theory of mind during childhood and adolescence YOSHIYA MORIGUCHI, md, phd,1,2,3 TAKASHI OHNISHI, md, phd,2,4,5 TAKEYUKI MORI, md, phd,2,5 HIROSHI MATSUDA, md, phd2,3 AND GEN KOMAKI, md, phd1 1

Department of Psychosomatic Research, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, 2Department of Radiology, National Center Hospital for Mental, Nervous, and Muscular Disorders, National Center of Neurology and Psychiatry, Kodaira 3Department of Nuclear Medicine, Saitama Medical School Hospital, Iruma, 4Department of Investigative Radiology, Research Institute of National Cardiovascular Center, Osaka and 5Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan

Abstract

Theory of mind (ToM) refers to the ability to attribute independent mental states, such as beliefs, preferences and desires, to the self and others. Neuroimaging studies of normal adults have consistently demonstrated the importance of particular brain regions for ToM, the superior temporal sulcus (STS), temporal pole (TP) and the medial prefrontal cortex (MPFC). However, there are little data showing how ToM develops during childhood and adolescence. Such data are important for understanding the development of social functioning and its disorders. The authors used functional magnetic resonance imaging to study age-related changes in brain activity associated with ToM during childhood and early adolescence (9–16 years). Normally developed children and adolescents demonstrated significant activation in the bilateral STS, the TP adjacent to the amygdala (TP/Amy) and the MPFC. Furthermore, the authors found a positive correlation between age and the degree of activation in the dorsal part of the MPFC; in contrast, a negative correlation was found for the ventral part of the MPFC.The authors also found a positive correlation between the Z coordinate of the peak activation in the MPFC and age. The data indicated that activity in the MPFC associated with ToM shifted from the ventral to the dorsal part of the MPFC during late childhood and adolescence. No age-related changes were found in the STS and the TP/Amy regions. The authors consider that the age-related brain activity observed in the present study may be associated with the maturation of the prefrontal cortex and the associated development of cognitive functions.

Key words

autism, functional magnetic resonance imaging, medial prefrontal cortex, normal development, theory of mind.

INTRODUCTION Human beings develop the ability to attribute independent mental states, such as beliefs, preferences, and desires, to the self and others in order to explain and

Correspondence address: Takashi Ohnishi, MD, PhD, Department of Radiology, National Center Hospital for Mental, Nervous, and Muscular Disorders, National Center of Neurology and Psychiatry, 4-1-1, Ogawa-Higashi Cho, Kodaira City, Tokyo 187–8551, Japan. Email: [email protected] Received 9 May 2006; revised 26 March 2007; accepted 15 April 2007.

predict the behavior of others. This is referred to as the theory of mind (ToM).1 ToM has been considered to be one of the essential independent cognitive domains for social interaction and cognition. Its impairment has been considered to be associated with deficits in social interaction and social functioning, such as found in the autistic spectrum disorders and schizophrenia.2,3 Neuroimaging studies have identified the neural substrates for ToM in the medial prefrontal cortex (MPFC), superior temporal sulcus (STS) and the temporal pole adjacent to the amygdala (TP/Amy) in normal adult individuals4 and in normal children.5 Furthermore, some studies demonstrated abnormal neural activities © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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in these areas in individuals with autistic disorders showing impairments of ToM.6–8 Particularly, the MPFC has been hypothesized to play a crucial role for ToM.9–19 According to Frith’s hypothesis,4 the MPFC may be the site of the decoupling mechanism that distinguishes the representation of one’s own mental state from the mental states of others and the reality of the physical world. Therefore, the MPFC seems to be responsible for the higher-order processing of ToM. Although most neuroimaging studies have been conducted with adult subjects, developmental psychologists who focus on the origins and early expressions of ToM have studied infants and young children. Behavioral studies revealed that most children are able to pass the first-order false belief test in their fourth year,20–22 However, there are little data showing how ToM develops beyond the age of about 7 years, when children have acquired understanding of second-order false beliefs.23 For example, it is not known whether the social sophistication of children older than 7 years of age is related to the acquisition of general knowledge and the maturation of general cognitive components or reflects the further development of ToM. Particularly, there is no data about how ToM develops during adolescence. Adolescence is a time of profound mental change affecting social awareness and adaptation. Several forms of mental illness, such as schizophrenia, begin during adolescence.24 Therefore, it is important to understand the cognitive and neural maturation during this period. A recent electrophysiological study demonstrated that the event-related potentials associated with the frontal cortex are still maturing into late adolescence, and that their amplitudes have significant correlations with behavioral capacities.25 Furthermore, several neuroimaging studies have focused on the process of brain maturation during childhood and adolescence.26–29 These studies have consistently suggested that maturation of the prefrontal cortex occurs during childhood, adolescence, and even during postadolescence.28 Considering these developmental changes of the prefrontal lobe and its functions, the cognitive abilities that rely on the frontal lobes such as ToM may also change during this period. In a previous functional magnetic resonance imaging (fMRI) study, the authors found that normally developed children (mean age, 10 years) had fully developed neural substrates forToM.5 To clarify the developmental changes of the neural substrates for ToM, the authors studied the age-related changes of brain activity during a ToM task in late childhood and early adolescence.The authors hypothesized that neural activities associated with ToM may change during late childhood and early adolescence, particularly in the MPFC. © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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METHOD Subjects A total of 16 right-handed, healthy children and adolescents (12 males and four females; mean (standard deviation [SD]) age, 13.4 (2.2) years; range, 9–16) participated in this study. All subjects were interviewed by medical doctors and confirmed to have no major medical or neurological or psychiatric disorders and no history of psychiatric and mental disorders including mental retardation. They all passed first and secondorder false belief tests23,30–33 and the normal development of the ToM ability of each subject was confirmed. Written informed consent was obtained from all subjects and their guardians in accord with the ethical guidelines of the local ethical committee.

Stimuli for functional magnetic resonance imaging measurements The authors used animations as the stimuli for fMRI measurements. The movie animation stimuli were essentially the same as the stimuli that were originally developed and used in a behavioral study by Abell et al.34 and subsequently were used in previous positron emission tomography (PET) studies conducted by Castelli et al.6,18 (Fig. 1 and the materials on the website http://www.icn.ucl.ac.uk/dev_group/research. htm). Eight silent animations were used during the fMRI scanning. All the animations featured two characters, a big red triangle and a small blue triangle, moving on a framed white background. Each sequence lasted 20 s, modified for the fMRI measurement. Two types of animations (four ToM animations and four random movement animations as a control condition) were matched for length. The scripts for the ToM sequences involved the two triangles persuading, bluffing, mocking, and surprising one another. The random movement animations showed the two triangles bouncing off the walls resembling the movement of billiard balls, or merely drifting about. While the type of movement was by definition different between the two conditions, the basic visual characteristics in terms of shape, overall speed, and orientation changes were as similar as possible.

Magnetic resonance imaging measurements All MRI measurements were performed with a 1.5 T Magnetom Vision plus MRI scanner (Siemens, Erlangen, Germany) using the standard head coil. Head motion was minimized by placing tight but comfortable foam padding around the subject’s head. Cerebral

Developmental aspects of theory of mind system

Figure 1. Example of theory of mind (ToM) task and control animation. Eight silent animations were used during functional magnetic resonance imaging. All the animations featured two characters, a big red triangle and a small blue triangle, moving on a framed white background. Each sequence lasted 20 s, modified for the functional magnetic resonance imaging measurement. Two types of animations (four ToM animations and four random movement animations as a control condition) were matched for length. The scripts for the ToM sequences involved the two triangles persuading, bluffing, mocking, and surprising one another. The random movement animations showed the two triangles bouncing off the walls resembling the movement of billiard balls, or merely drifting about. While the type of movement was by definition different between the two conditions, the basic visual characteristics in terms of shape, overall speed, and orientation changes were as similar as possible.

activation was measured with fMRI using blood oxygen level-dependent contrast.35,36 After automatic shimming, a time course series of 125 volumes was obtained using single-shot gradient-refocused echoplanar imaging (TR 4000 ms; TE 60 ms; flip angle 90 degree; interscan interval 4 s; in-plane resolution 3.44 ¥ 3.44 mm; FOV 22 cm; contiguous 4 mm slices to cover the entire brain). The fMRI protocol was a block design with two kinds of epochs of the ToM animation condition and the control (random movement) condition. Each epoch lasted 20 s (equivalent to five whole-brain fMRI volume acquisitions) and consisted of one script. Each script of task and control conditions was used twice in one session, so there were eight task and eight control blocks. The first five volumes of each fMRI scan were discarded because of non-steady magnetization and the remaining 120 volumes were used for the analysis. Before each fMRI experiment, subjects were told to watch the animations and think about what the triangles were doing and thinking during the scanning. After each scan, the subjects again watched the same

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stimuli on a computer screen outside the scanner and were asked to recall what they had thought, during the fMRI scan, that the triangles had been doing. To check that the subject had been engaged well in the task, the subjects were asked to tell the experimenter what they had thought, in response to the experimenter’s neutral question: ‘What was happening in this animation?’ Their verbal descriptions were coded on four different dimensions: ‘Intentionality’, ‘Appropriateness’, ‘Certainty’, and ‘Length’. Detailed scoring procedures are given in the report by Castelli et al.6,18 The stimuli were presented using a Windows PC and back projected onto a screen, ~50 cm from the subject’s head, using a 65 536-color liquid crystal display and an overhead projector. The subjects viewed the screen through a mirror attached to the head coil. A 3-D volumetric acquisition of a T1-weighted gradient echo sequence produced a gapless series of thin sagittal sections using a magnetization prepared rapid acquisition with gradient echo sequence (MPRAGE; TE/TR, 4.4/ 11.4 ms; flip angle, 15 degree; acquisition matrix, 256 ¥ 256; 1NEX field of view, 31.5 cm; slice thickness, 1.23 mm).

Data analysis Data were analyzed with the Statistical Parametric Mapping software (SPM2, http://www.fil.ion.ucl.ac.uk/ spm). Scans were realigned and EPI BOLD images were summed and coregistered to the subject’s T1-weighted MRI. Then the T1-weighted MRI were transformed to the standard stereotactic space of the MNI (Montreal Neurological Institute) using a T1weighted MRI template whose space can convert to the Talairach space.37 The parameter for affine and quadratic transformation to the T1-weighted MRI template that was already fitted for the Talairach space was estimated by least-squares means. This transformation was applied to the coregistered EPI BOLD images. Data were then smoothed in a spatial domain (full width at half-maximum, 8 ¥ 8 ¥ 8 mm) to improve the signal to noise ratio. After specifying the appropriate design matrix, the hemodynamic response function as a reference waveform, the condition and slow hemodynamic fluctuations unrelated to the task were estimated according to a general linear model taking temporal smoothness into account.Global normalization was performed using proportional scaling. To test the hypotheses about regionally specific condition effects, the estimates were compared by means of linear contrasts for each epoch.The resulting set of voxel values for each contrast constituted a statistical parametric map of the t statistic SPM {t}. Anatomic localization was according to both MNI coordinates and Talairach coordinates, © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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obtained from M. Brett’s transformations (http:// www.mrc-cbu.cam.ac.uk/Imaging/mnispace.html) and presented as Talairach coordinates.To account for interindividual variance, all group analyses were computed using a random-effects model.38 Group analysis across subjects involved a one-sample t-test on the whole brain images generated by pooling over the session the individual contrasts of task versus control activation for each subject. The significant voxels and clusters were given a threshold at P < 0.001 and the extent of cluster >50 voxels. The authors also applied hypothesis-driven region of interest (ROI) analyses to test age-related changes of degree of activation in the neural substrates for ToM (the STS, Temporal pole, and the MPFC). For these ROI analyses, the authors used the Wake Forest University PickAtlas39 with a correlation analysis between the degree of activation associated with ToM and age. In the correlation analysis, the authors treated age as a covariate of interest and treated gender as a nuisance variable. The significant voxels and clusters were given a threshold at P < 0.005 without a correction for multiple comparisons.

RESULTS Behavioral scoring of theory of mind task and age There is no correlation between age and scoring of verbal descriptions of each dimension (‘Intentionality’;

r = -0.22, P = 0.41, ‘Appropriateness’; r = -0.03, P = 0.91, ‘Certainty’; r = 0.05, P = 0.85, and ‘Length’; r = -0.04, P = 0.89).

Brain activity associated with theory of mind in late childhood and adolescence Table 1 and Fig. 2 show activities associated with ToM for all subjects as revealed by a one-sample t-test. A significant activation was noted in the bilateral (right > left) STS, the TP/Amy region, and the MPFC. In addition, the right inferior frontal gyrus [Brodmann area (BA) 45], middle frontal gyrus (premotor area, BA6/8), left posterior cerebellum, inferior/middle occipital lingual gyrus (BA18), right caudate and putamen, right precuneus (BA7/31), bilateral fusiform gyri (BA37) and left inferior/middle temporal gyrus (BA21) were also significantly activated.

Correlation analyses In the correlation analysis for age-associated changes of activities in the MPFC, the STS, and the TP/Amy region, significant correlations between age and the degree of activation were found only in the MPFC. A significant positive correlation with age was noted in the dorsal part of the MPFC (Talairach coordinate: -6, 57, 14; Fig. 3a), whereas a significant negative correlation with

Table 1. Brain activation in response to theory of mind-related task compared to control condition by one sample t-test of all subjects throughout whole brain Talairach coordinate

Rt Lt Rt Rt Rt Lt Lt Rt Rt Lt Rt Lt Rt Rt Rt Lt Rt

Region

BA

x

y

z

Z

Cluster size (voxels)

Superior Temporal Sulcus Superior Temporal Sulcus Temporal Pole/Uncus Medial Prefrontal cortex Medial Prefrontal cortex Inferior/Middle Temporal Gyrus Cerebellum Posterior Lobe Tuber Inferior Frontal Gyrus Middle Frontal Gyrus (premotor) Middle Frontal Gyrus (premotor) Medial Prefrontal Gyrus Inferior/Middle Occipital, Lingual Gyrus Precuneus Caudate body Fusiform Gyrus Fusiform Gyrus Lentiform Nucleus, Putamen

22 22 28/38 10 9 21 – 45 6/8 6/9 8 18 7/31 – 37 37 –

51 -51 32 14 4 -55 -24 50 50 -42 6 -34 10 14 -42 44 16

-47 -48 5 63 50 -14 -81 31 10 7 35 -90 -51 12 -51 -51 11

1 12 -24 13 29 -16 -28 4 42 22 42 -6 38 10 -16 -16 -4

5.65 5.48 4.35 4.17 3.67 3.65 4.71 7.03 4.31 3.97 4.33 4.32 3.82 4.1 4.51 4.96 4.06

5461 1965 186 81 72 82 426 798 1214 120 50 159 56 131 1965 5461 131

Height threshold: T = 3.73, P = 0.001; extent threshold: k = 50 voxels. BA, Brodmann area. © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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Figure 2. Activation associated with theory of mind in normal children and adolescents. Statistical parametric mapping {t} is rendered onto a normalized template brain image. Amy, amygdala; MPFC, medial prefrontal cortex; PM, premotor area; STS, superior temporal sulcus; TP, temporal pole.

Figure 3. Results of correlation analyses. Statistical parametric mapping {t} is rendered onto T1-weighted magnetic resonance images. (a) A significant positive correlation between age and degree of activation in the medial prefrontal cortex (MPFC) was noted in the dorsal part of the MPFC (Talairach coordinate: -6, 57, 14; t = 4.34; r = 0.72). (b) A significant negative correlation between age and degree of activation in the MPFC was noted in the ventral part of the MPFC (Talairach coordinate: 10, 43, 0; t = 5.49; r = 0.82).

age was noted in the more ventral part of the MPFC (Talairach coordinate: 10, 43, 0; Fig. 3b). The ventral medial prefrontal cortex was activated in a child group in a fixed first-level analysis (n = 6, ⱕ12 years of age; Talairach coordinate: 12, 44, -4; T = 3.81, Z = 3.80, cluster extent k = 51: height and extent threshold; P = 0.001 uncorrected and k = 20). No significant correlation was

found between age and the degree of activation in the STS and the TP/Amy. It was supposed that the activation in the MPFC may shift from a ventral to a dorsal part of the MPFC with aging or maturation. Further, the authors added an evaluation of the correlation between the Y and Z coordinate of the peak activation in the MPFC and age in each subject. To reduce the false © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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Figure 4. The graph shows the correlation between age and Z coordinates in the Talairach space for each peak activation in the medial prefrontal cortex. A significant positive correlation was noted. [r = 0.78; P = 0.00037; regression line: (Z coordinate) = 6.78 ¥ (age) - 73.8].

negatives, the locus of the maximum MPFC peak in each subject was searched at a lenient height and extent threshold (P < 0.05 uncorrected and P < 0.05 volume corrected within the ROI defined by medial part of Brodmann area 9, 10, 11, and 32 using the Wake Forest University PickAtlas software) at the fixed level subject-wise analysis. There was a significantly positive correlation between the Z coordinates and age [(Z coordinate) = 6.78 ¥ (age) - 73.8, r = 0.78, P = 0.00037); Fig. 4], although there is not a significant correlation between the Y coordinates and age (r = 0.33 P = 0.29). There is no significant correlation between ToMrelated brain activity and scoring of verbal descriptions of each dimension.

DISCUSSION In this study, the authors focused on the developmental aspects of the neural substrates for ToM.As the authors demonstrated in a previous fMRI study with normal children,5 they found activation in the three major loci: MPFC, STS, and TP/Amy regions. These regions have been consistently shown to be important neural substrates for ToM in previous studies with adult subjects.4 In addition, the authors also found ToM-related activation in the cerebellum, dorsal premotor area and the fusiform gyri. Some neuroimaging studies with adults also demonstrated that these regions may be associated with ToM and social cognition.40–42 The current data © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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indicate that children and adolescents have essentially the same neural substrates for ToM as adults. Notably, the authors found age-associated changes in the activation pattern in the MPFC, which is a crucial neural substrate for ToM. Activities in other important neural components for ToM, such as the STS and the TP/Amy region, did not show any age-associated changes. Regarding activity in the MPFC, a significant positive correlation between age and the degree of activation was noted in more dorsal part of the MPFC (BA9/ 10). This location (Talaraich coordinate (mm); x = -6, y = 57, z = (14)) is similar to that of a previous PET study of ToM with adult subjects (BA9; x = 10, y = 54, z = 30).6 In contrast, a negative correlation was found in more ventral part of the MPFC (BA32/10; x = 10, y = 43, z = 0). Furthermore, the Z coordinates of the individual activation peak in the MPFC positively correlated with age. These results indicate that the MPFC activation associated with ToM shifted with age from the ventral to the dorsal portion of the MPFC. Different regions of MPFC play different roles in thinking about intentions. A neuroimaging study revealed holding in mind an intention to act and at the same time thinking about an intentional action led to reduced activity in a dorsal section of the MPFC, which was a different region from a more anterior, inferior dorsal MPFC region that responded to intentional causality.43 A recent meta-analysis demonstrated that the medial prefrontal functions were segregated into cognitive and emotional functions.44 The ventral MPFC was recruited when tasks had emotional contexts, whereas the dorsal MPFC was recruited when tasks required primarily cognitive demands. Furthermore, in previous reports, different loci of the MPFC were engaged by different kinds of mentalizing tasks.45 The dorsal MPFC loci reported in several investigations were related to mentalizing trials with more social cognitive demands.15,19,46,47 Otherwise the ventral MPFC loci reported in previous studies were related to mentalizing with inner self-referential processing.48–54 Mitchell et al.45 hypothesized that the ventral MPFC may guide the understanding of others’ mental states through examining the individual’s own mental state or simulating in the self the possible mental state of others. Otherwise the dorsal MPFC may instead represent more universally applicable social-cognitive processes that can aid mentalizing even when simulation is inappropriate (e.g. for dissimilar others). Taken together, the shifting of MPFC activity from the ventral to the dorsal portion could be interpreted as the maturation of the ToM system, which is changing from using only the developmentally earlier simulating system to using additional cognitive comprehension of others.

Developmental aspects of theory of mind system

The authors speculate that the older subjects in the present study try to ‘read the minds’ of the animated triangles in a more cognitive way than the younger subjects. The authors assume that the anatomical and functional maturation of the prefrontal cortex from late childhood to early adolescence may underlie developmental change of the ToM system. Previous neuroimaging studies have demonstrated heterochronic development in the human cerebral cortex and revealed late maturation of the prefrontal and temporal association cortices.26–29 One study demonstrated that the maturation of the PFC continued even during postadolescence.28 Also, behavioral studies have revealed age-related improvement in performance in frontal functions, such as the executive function, from childhood to late adolescence.55 Further, a recent study56 found a marked developmental shift from a predominantly negative correlation between intelligence and cortical thickness in early childhood to a positive correlation in late childhood and beyond, and this trajectory of change in the thickness of the cerebral cortex was found most primarily in frontal regions including MPFC. These results support the authors’ notion that the changes in the MPFC activity in the present study seem to be developmental changes of the neural substrates for ToM and the underlying maturation of the PFC. However, it is still inconclusive whether the more dorsal region activated in the older children is functionally homologous to the more ventral region activated in the younger children. Further studies will be needed to look at the relationship between anatomical change in the mentalizing network and actual mentalizing behavior. In contrast, the activity in the STS and the TP/Amy regions did not show age-related changes. The authors consider that the functions of these areas for ToM may have matured before late childhood. A lesion study of early and late damage to the human amygdala demonstrated that subjects with lesions of the amygdala arising in early childhood showed impaired ToM ability, whereas subjects who acquired damage to the amygdala in adulthood did not.57 The posterior STS is a heteromodal association (along with prefrontal and inferior parietal cortices) and is involved with integration of memory, audiovisual association, and objectrecognition functions.58–60 Important functions in the posterior STS involve social perception using visual information, for example biological motion,61–63 gaze direction,64–67 and the mirror neuron system.5 All of these were found even in monkeys while monkeys are inferred not to have entire ToM ability, and have been regarded as more basic precursors for ToM.4 Behaviorally, before the age of four when most children can pass the first-order false belief test, children have acquired

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these precursors for ToM, such as detection of gaze direction68 and joint attention,69 which are associated with the STS4. Therefore, these facts suggest that the functional maturation of the STS as a part of ToM may have been almost completed before the age of nine. Perhaps this may have accounted for the lack of agerelated changes in the STS in the present study. In the present study, the authors could not find agerelated change of ToM scorings and brain activities. One possible explanation is that ToM ability might be more associated with subject’s personal achievement of mentalizing ability in individual cases than ageassociated developmental effects. Another explanation is that subjects were equally engaged in inferring mental states in the task movies, regardless of its accuracy, which possibly resulted in no association between ToM scorings and brain activities. In future, longitudinal study of ToM-related behavioral performance and brain activity will be needed to clarify more detailed developmental factors of ToM. A potential weakness of the study is the usage of an adult brain template for normalization of the EPI images, which might affect the correlation between ages and peak Z coordinates in the MPFC activations. Development and usage of a child brain template would be needed to confirm the result for the future. In conclusion, in late childhood and early adolescence, normal individuals have essentially the same pattern of brain activities associated with ToM as observed in previous studies with normal adults. Importantly, the authors found age-related changes of activities in the MPFC that may be associated with the functional development of the prefrontal cortex. Although a detailed behavioral study is needed, the present data suggest that the neural system for ToM may continue to develop beyond the age of 7 years, when most children can understand second-order false beliefs.

ACKNOWLEDGMENTS This research was supported by a Health Science Research Grant from the Ministry of Health, Labour and Welfare (H17-kokoro-007). The authors wish to thank Professor Uta Frith, Institute of Cognitive Neuroscience and Department of Psychology, University College London, for providing animations as fMRI stimuli.

REFERENCES 1. Premack D, Woodruff G. Chimpanzee problem-solving: a test for comprehension. Science 1978; 202: 532–535. © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

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2. Povinelli DJ, Preuss TM. Theory of mind: evolutionary history of a cognitive specialization. Trends Neurosci. 1995; 18: 418–424. 3. Siegal M, Varley R. Neural systems involved in ‘theory of mind’. Nat. Rev. Neurosci. 2002; 3: 463–471. 4. Frith U, Frith CD. Development and neurophysiology of mentalizing. Philos. Trans. R. Soc. Lond. B Biol. Sci. 2003; 358: 459–473. 5. Ohnishi T, Moriguchi Y, Matsuda H et al. The neural network for the mirror system and mentalizing in normally developed children: an fMRI study. Neuroreport 2004; 15: 1483–1487. 6. Castelli F, Frith C, Happe F, Frith U. Autism, Asperger syndrome and brain mechanisms for the attribution of mental states to animated shapes. Brain 2002; 125: 1839– 1849. 7. Happe F, Ehlers S, Fletcher P et al. ‘Theory of mind’ in the brain. Evidence from a PET scan study of Asperger syndrome. Neuroreport 1996; 8: 197–201. 8. Ohnishi T, Matsuda H, Hashimoto T et al. Abnormal regional cerebral blood flow in childhood autism. Brain 2000; 123 (Part 9): 1838–1844. 9. Calder AJ, Lawrence AD, Keane J et al. Reading the mind from eye gaze. Neuropsychologia 2002; 40: 1129– 1138. 10. Gregory C, Lough S, Stone V et al. Theory of mind in patients with frontal variant frontotemporal dementia and Alzheimer’s disease: theoretical and practical implications. Brain 2002; 125: 752–764. 11. McCabe K, Houser D, Ryan L, Smith V, Trouard T. A functional imaging study of cooperation in two-person reciprocal exchange. Proc. Natl Acad. Sci. USA 2001; 98: 11832–11835. 12. Rowe AD, Bullock PR, Polkey CE, Morris RG. ‘Theory of mind’ impairments and their relationship to executive functioning following frontal lobe excisions. Brain 2001; 124: 600–616. 13. Shallice T. ‘Theory of mind’ and the prefrontal cortex. Brain 2001; 124: 247–248. 14. Stuss DT, Gallup GG Jr, Alexander MP. The frontal lobes are necessary for ‘theory of mind’. Brain 2001; 124: 279–286. 15. Goel V, Grafman J, Sadato N, Hallett M. Modeling other minds. Neuroreport 1995; 6: 1741–1746. 16. Fletcher PC, Happe F, Frith U et al. Other minds in the brain: a functional imaging study of ‘theory of mind’ in story comprehension. Cognition 1995; 57: 109– 128. 17. Gallagher HL, Happe F, Brunswick N, Fletcher PC, Frith U, Frith CD. Reading the mind in cartoons and stories: an fMRI study of ‘theory of mind’ in verbal and nonverbal tasks. Neuropsychologia 2000; 38: 11–21. 18. Castelli F, Happe F, Frith U, Frith C. Movement and mind: a functional imaging study of perception and interpretation of complex intentional movement patterns. Neuroimage 2000; 12: 314–325. 19. Gallagher HL, Jack AI, Roepstorff A, Frith CD. Imaging the intentional stance in a competitive game. Neuroimage 2002; 16: 814–821. © 2007 The Authors Journal compilation © 2007 Folia Publishing Society

Y. Moriguchi et al.

20. Gopnik A, Slaughter V. Young children’s understanding of changes in their mental states. Child Dev. 1991; 62: 98–110. 21. Wimmer H, Haiti M. Against the Cartesian view on mind: young children’s difficulty with own false beliefs. Br. J. Dev. Psychol. 1991; 9: 125–138. 22. Wimmer H, Perner J. Beliefs about beliefs: representation and constraining function of wrong beliefs in young children’s understanding of deception. Cognition 1983; 13: 103–128. 23. Perner J, Wimmer H. ‘Joseph thinks that Mary thinks that.’ Attribution of second-order beliefs by 5- to 10-yearold children. J. Exp. Psychol. 1985; 39: 437–471. 24. Thompson JL, Pogue-Geile MF, Grace AA. Developmental pathology, dopamine, and stress: a model for the age of onset of schizophrenia symptoms. Schizophr Bull. 2004; 30: 875–900. 25. Segalowitz SJ, Davies PL. Charting the maturation of the frontal lobe: an electrophysiological strategy. Brain Cogn. 2004; 55: 116–133. 26. Giedd JN, Blumenthal J, Jeffries NO et al. Brain development during childhood and adolescence: a longitudinal MRI study. Nat. Neurosci. 1999; 2: 861–863. 27. Gogtay N, Giedd JN, Lusk L et al. Dynamic mapping of human cortical development during childhood through early adulthood. Proc. Natl Acad. Sci. USA 2004; 101: 8174–8179. 28. Sowell ER, Peterson BS, Thompson PM, Welcome SE, Henkenius AL, Toga AW. Mapping cortical change across the human life span. Nat. Neurosci. 2003; 6: 309–315. 29. Sowell ER, Thompson PM, Holmes CJ, Batth R, Jernigan TL, Toga AW. Localizing age-related changes in brain structure between childhood and adolescence using statistical parametric mapping. Neuroimage 1999; 9: 587– 597. 30. Baron-Cohen S, Leslie AM, Frith U. Does the autistic child have a ‘theory of mind’? Cognition 1985; 21: 37–46. 31. Perner J, Frith U, Leslie AM, Leekam SR. Exploration of the autistic child’s theory of mind: knowledge, belief, and communication. Child Dev. 1989; 60: 688–700. 32. Sullivan K, Zaitchik D, Tager-Flusberg H. Preschoolers can attribute second-order beliefs. Dev. Psychol. 1994; 30: 395–402. 33. Koike T, Fujino H. Assessment Software for Children:The Animation Version of ‘Theory of Mind’ Test. DIK, Tokyo, 2002 (in Japanese). 34. Abell F, Happé F, Frith U. Do triangles play tricks? Attribution of mental states to animated shapes in normal and abnormal development. J. Cogn. Dev. 2000; 15: 1–20. 35. Ogawa S, Lee TM, Kay AR, Tank DW. Brain magnetic resonance imaging with contrast dependent on blood oxygenation. Proc. Natl Acad. Sci. USA 1990; 87: 9868– 9872. 36. Ogawa S, Tank DW, Menon R et al. Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging. Proc. Natl Acad. Sci. USA 1992; 89: 5951–5955. 37. Talairach J, Tournoux P. Co-Planar Stereotaxic Atlas of the Human Brain. Thieme, New York, 1988.

Developmental aspects of theory of mind system

38. Friston KJ, Holmes AP, Worsley KJ. How many subjects constitute a study? Neuroimage 1999; 10: 1–5. 39. Maldjian JA, Laurienti PJ, Kraft RA, Burdette JH. An automated method for neuroanatomic and cytoarchitectonic atlas-based interrogation of fMRI data sets. Neuroimage 2003; 19: 1233–1239. 40. Brunet E, Sarfati Y, Hardy-Bayle MC, Decety J. A PET investigation of the attribution of intentions with a nonverbal task. Neuroimage 2000; 11: 157–166. 41. Calarge C, Andreasen NC, O’Leary DS. Visualizing how one brain understands another: a PET study of theory of mind. Am. J. Psychiatry 2003; 160: 1954–1964. 42. Schultz RT, Grelotti DJ, Klin A et al. The role of the fusiform face area in social cognition: implications for the pathobiology of autism. Philos. Trans. R. Soc. Lond. B Biol. Sci. 2003; 358: 415–427. 43. den Ouden HE, Frith U, Frith C, Blakemore SJ. Thinking about intentions. Neuroimage 2005; 28: 787–796. 44. Steele JD, Lawrie SM. Segregation of cognitive and emotional function in the prefrontal cortex: a stereotactic meta-analysis. Neuroimage 2004; 21: 868–875. 45. Mitchell JP, Banaji MR, Macrae CN. The link between social cognition and self-referential thought in the medial prefrontal cortex. J. Cogn. Neurosci. 2005; 17: 1306– 1315. 46. Mitchell JP, Heatherton TF, Macrae CN. Distinct neural systems subserve person and object knowledge. Proc. Natl Acad. Sci. USA 2002; 99: 15238–15243. 47. Mitchell JP, Macrae CN, Banaji MR. Encodingspecific effects of social cognition on the neural correlates of subsequent memory. J. Neurosci. 2004; 24: 4912– 4917. 48. Gusnard DA, Akbudak E, Shulman GL, Raichle ME. Medial prefrontal cortex and self-referential mental activity: relation to a default mode of brain function. Proc. Natl Acad. Sci. USA 2001; 98: 4259–4264. 49. Johnson SC, Baxter LC, Wilder LS, Pipe JG, Heiserman JE, Prigatano GP. Neural correlates of self-reflection. Brain 2002; 125: 1808–1814. 50. Kelley WM, Macrae CN, Wyland CL, Caglar S, Inati S, Heatherton TF. Finding the self? An event-related fMRI study. J. Cogn. Neurosci. 2002; 14: 785–794. 51. Macrae CN, Moran JM, Heatherton TF, Banfield JF, Kelley WM. Medial prefrontal activity predicts memory for self. Cereb. Cortex. 2004; 14: 647–654. 52. Schmitz TW, Kawahara-Baccus TN, Johnson SC. Metacognitive evaluation, self-relevance, and the right prefrontal cortex. Neuroimage 2004; 22: 941–947. 53. Vogeley K, May M, Ritzl A, Falkai P, Zilles K, Fink GR. Neural correlates of first-person perspective as one constituent of human self-consciousness. J. Cogn. Neurosci. 2004; 16: 817–827.

363

54. Zysset S, Huber O, Ferstl E, von Cramon DY. The anterior frontomedian cortex and evaluative judgment: an fMRI study. Neuroimage 2002; 15: 983–991. 55. Anderson VA, Anderson P, Northam E, Jacobs R, Catroppa C. Development of executive functions through late childhood and adolescence in an Australian sample. Dev. Neuropsychol. 2001; 20: 385–406. 56. Shaw P, Greenstein D, Lerch J et al. Intellectual ability and cortical development in children and adolescents. Nature 2006; 440: 676–679. 57. Shaw P, Lawrence EJ, Radbourne C, Bramham J, Polkey CE, David AS. The impact of early and late damage to the human amygdala on ‘theory of mind’ reasoning. Brain 2004; 127: 1535–1548. 58. Calvert GA, Martin A, Chao LL. Crossmodal processing in the human brain: insights from functional neuroimaging studies. Semantic memory and the brain: structure and processes. Curr. Opin. Neurobiol. 2001; 11: 194–201. 59. Martin A, Chao LL. Semantic memory and the brain: structure and processes. Curr. Opin. Neurobiol. 2001; 11: 194–201. 60. Mesulam MM. From sensation to cognition. Brain 1998; 121 (Part 6): 1013–1052. 61. Giese MA, Poggio T. Neural mechanisms for the recognition of biological movements. Nat. Rev. Neurosci. 2003; 4: 179–192. 62. Jellema T, Baker CI, Wicker B, Perrett DI. Neural representation for the perception of the intentionality of actions. Brain Cogn. 2000; 44: 280–302. 63. Perrett DI, Harries MH, Bevan R et al. Frameworks of analysis for the neural representation of animate objects and actions. J. Exp. Biol. 1989; 146: 87–113. 64. Allison T, Puce A, McCarthy G. Social perception from visual cues: role of the STS region. Trends Cogn. Sci. 2000; 4: 267–278. 65. Pageler NM, Menon V, Merin NM, Eliez S, Brown WE, Reiss AL. Effect of head orientation on gaze processing in fusiform gyrus and superior temporal sulcus. Neuroimage 2003; 20: 318–329. 66. Puce A, Allison T, Bentin S, Gore JC, McCarthy G. Temporal cortex activation in humans viewing eye and mouth movements. J. Neurosci. 1998; 18: 2188–2199. 67. Wicker B, Michel F, Henaff MA, Decety J. Brain regions involved in the perception of gaze: a PET study. Neuroimage 1998; 8: 221–227. 68. Butterworth G, Jarrett N. What minds have in common is space-spatial mechanisms serving joint visual-attention in infancy. Br. J. Dev. Psychol. 1991; 9: 55–72. 69. Carpenter M, Nagell K, Tomasello M. Social cognition, joint attention, and communicative competence from 9 to 15 months of age. Monogr. Soc. Res. Child Dev. 1998; 634: i–vi, 1–143.

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