'Theory of mind' in the brain. Evidence from a PET scan study of Asperger syndrome

Emotional responses associated with self-face processing in individuals with autism spectrum disorders: an fMRI study

Individuals with autism spectrum disorders (ASD) show impaired emotional responses to self-face processing, but the underlying neural bases are unclear. Using functional magnetic resonance imaging, we investigated brain activity when 15 individuals with high-functioning ASD and 15 controls rated the photogenicity of self-face images and photographs of others' faces. Controls showed a strong correlation between photogenicity ratings and extent of embarrassment evoked by self-face images; this correlation was weaker among ASD individuals, indicating a decoupling between the cognitive evaluation of self-face images and emotional responses. Individuals with ASD demonstrated relatively low self-related activity in the posterior cingulate cortex (PCC), which was related to specific autistic traits. There were significant group differences in the modulation of activity by embarrassment ratings in the right insular (IC) and lateral orbitofrontal cortices. Task-related activity in the right IC was lower in the ASD group. The reduced activity in the right IC for self-face images was associated with weak coupling between cognitive evaluation and emotional responses to self-face images. The PCC is responsible for self-referential processing, and the IC plays a role in emotional experience. Dysfunction in these areas could contribute to the lack of self-conscious behaviors in response to self-reflection in ASD individuals.

The development of aesthetic responses to music and their underlying neural and psychological mechanisms

In the field of psychology, the first studies in experimental aesthetics were conducted approximately 140 years ago. Since then, research has mainly concentrated on aesthetic responses to visual art. Both the aesthetic experience of music and, especially, its development have received rather limited attention. Moreover, until now, very little attention has been paid to the investigation of the aesthetic experience of music using neuroscientific methods. Aesthetic experiences are multidimensional and include inter alia sensory, perceptual, affective, and cognitive components. Aesthetic processes are usually experienced as pleasing and rewarding and are, thus, important and valuable experiences for many people. Because of their multidimensional nature, these processes employ several brain areas. In the present review, we examine important psychological and neural mechanisms that are believed to contribute to the development of aesthetic experiences of music. We also discuss relevant research findings. With the present review, we wish to provoke further discussion and possible future investigations as we consider the investigation of aesthetic experiences to be important both scientifically and with respect to potential clinical applications.

How we empathize with others: a neurobiological perspective

Empathy allows us to internally simulate the affective and cognitive mental states of others. Neurobiological studies suggest that empathy is a complex phenomenon, which can be described using a model that includes 2 modes of processing: bottom-up and top-down. Bottom-up neural processing is achieved via the mirroring representation systems that play a key role in the direct sharing of the emotional states of others. Top-down processing, known as cognitive perspective-taking or theory of mind, where the feelings of others are fully imagined and understood, is based on control and inhibition mechanisms. Available evidence indicates that empathic brain responses are likely to be influenced by several different modulating factors.

Early processing of emotional faces in children with autism: An event-related potential study

Social deficits are one of the most striking manifestations of autism spectrum disorders (ASDs). Among these social deficits, the recognition and understanding of emotional facial expressions has been widely reported to be affected in ASDs. We investigated emotional face processing in children with and without autism using event-related potentials (ERPs). High-functioning children with autism (n=15, mean age=10.5±3.3 years) completed an implicit emotional task while visual ERPs were recorded. Two groups of typically developing children (chronological age-matched and verbal equivalent age-matched [both ns=15, mean age=7.7±3.8 years]) also participated in this study. The early ERP responses to faces (P1 and N170) were delayed, and the P1 was smaller in children with autism than in typically developing children of the same chronological age, revealing that the first stages of emotional face processing are affected in autism. However, when matched by verbal equivalent age, only P1 amplitude remained affected in autism. Our results suggest that the emotional and facial processing difficulties in autism could start from atypicalities in visual perceptual processes involving rapid feedback to primary visual areas and subsequent holistic processing.

White matter integrity in Asperger syndrome: a preliminary diffusion tensor magnetic resonance imaging study in adults

BACKGROUND

Autistic Spectrum Disorder (ASD), including Asperger syndrome and autism, is a highly genetic neurodevelopmental disorder. There is a consensus that ASD has a biological basis, and it has been proposed that it is a "connectivity" disorder. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) allows measurement of the microstructural integrity of white matter (a proxy measure of "connectivity"). However, nobody has investigated the microstructural integrity of whole brain white matter in people with Asperger syndrome.

METHODS

We measured the fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD) of white matter, using DT-MRI, in 13 adults with Asperger syndrome and 13 controls. The groups did not differ significantly in overall intelligence and age. FA, MD and RD were assessed using whole brain voxel-based techniques.

RESULTS

Adults with Asperger syndrome had a significantly lower FA than controls in 13 clusters. These were largely bilateral and included white matter in the internal capsule, frontal, temporal, parietal and occipital lobes, cingulum and corpus callosum.

CONCLUSIONS

Adults with Asperger syndrome have widespread significant differences from controls in white matter microstructural integrity.

Neuropsychologische Modelle von Autismus-Spektrum-Störungen

Fragestellung: Der Artikel gibt einen Überblick über die Modelle der Theory of Mind (ToM), Exekutivfunktionen (EF) und Zentralen Kohärenz (ZK), welche die neuropsychologischen Auffälligkeiten bei Menschen mit Autismus-Spektrum Störungen (ASS) treffend zu beschreiben vermögen. Methodik: In einem selektiven Review werden Ergebnisse behavioraler und funktionell-bildgebender Arbeiten zu den sozial-kognitiven, emotionalen und exekutiven Funktionen sowie der lokal-orientierten Wahrnehmung bei ASS berichtet. Ergebnisse: Beeinträchtigungen in ToM und EF sowie Besonderheiten in ZK sind vielfach replizierte Phänomene bei ASS. Vor allem soziale Wahrnehmungsprobleme und ToM haben einen hohen Erklärungswert für die klinische Symptomatik von ASS. Cerebrale Aktivierungsmuster unterscheiden sich bei Menschen mit und ohne ASS für ToM, EF und ZK. Als übergeordnetes neurales Erklärungsmodell scheint sich verringerte Konnektivität rekrutierter kortikaler Netzwerke gegen das Konzept einzelner betroffener Gehirnareale durchzusetzen. Schlussfolgerungen: Für ein besseres Verständnis der komplexen Zusammenhänge bei ASS ist eine zukünftige Integration klinischer, neuropsychologischer, funktionell-bildgebender und molekulargenetischer Befunde essenziell. Schwächen bei ToM und EF sowie Stärken in den Bereichen detail-orientierte Wahrnehmung sollten bei der individuellen Interventionsplanung verstärkt Eingang finden.

The intense world theory - a unifying theory of the neurobiology of autism

Autism covers a wide spectrum of disorders for which there are many views, hypotheses and theories. Here we propose a unifying theory of autism, the Intense World Theory. The proposed neuropathology is hyper-functioning of local neural microcircuits, best characterized by hyper-reactivity and hyper-plasticity. Such hyper-functional microcircuits are speculated to become autonomous and memory trapped leading to the core cognitive consequences of hyper-perception, hyper-attention, hyper-memory and hyper-emotionality. The theory is centered on the neocortex and the amygdala, but could potentially be applied to all brain regions. The severity on each axis depends on the severity of the molecular syndrome expressed in different brain regions, which could uniquely shape the repertoire of symptoms of an autistic child. The progression of the disorder is proposed to be driven by overly strong reactions to experiences that drive the brain to a hyper-preference and overly selective state, which becomes more extreme with each new experience and may be particularly accelerated by emotionally charged experiences and trauma. This may lead to obsessively detailed information processing of fragments of the world and an involuntarily and systematic decoupling of the autist from what becomes a painfully intense world. The autistic is proposed to become trapped in a limited, but highly secure internal world with minimal extremes and surprises. We present the key studies that support this theory of autism, show how this theory can better explain past findings, and how it could resolve apparently conflicting data and interpretations. The theory also makes further predictions from the molecular to the behavioral levels, provides a treatment strategy and presents its own falsifying hypothesis.

Normal variation in fronto-occipital circuitry and cerebellar structure with an autism-associated polymorphism of CNTNAP2

Recent genetic studies have implicated a number of candidate genes in the pathogenesis of Autism Spectrum Disorder (ASD). Polymorphisms of CNTNAP2 (contactin-associated like protein-2), a member of the neurexin family, have already been implicated as a susceptibility gene for autism by at least 3 separate studies. We investigated variation in white and grey matter morphology using structural MRI and diffusion tensor imaging. We compared volumetric differences in white and grey matter and fractional anisotropy values in control subjects characterised by genotype at rs7794745, a single nucleotide polymorphism in CNTNAP2. Homozygotes for the risk allele showed significant reductions in grey and white matter volume and fractional anisotropy in several regions that have already been implicated in ASD, including the cerebellum, fusiform gyrus, occipital and frontal cortices. Male homozygotes for the risk alleles showed greater reductions in grey matter in the right frontal pole and in FA in the right rostral fronto-occipital fasciculus compared to their female counterparts who showed greater reductions in FA of the anterior thalamic radiation. Thus a risk allele for autism results in significant cerebral morphological variation, despite the absence of overt symptoms or behavioural abnormalities. The results are consistent with accumulating evidence of CNTNAP2's function in neuronal development. The finding suggests the possibility that the heterogeneous manifestations of ASD can be aetiologically characterised into distinct subtypes through genetic-morphological analysis.

Deficits in facial, body movement and vocal emotional processing in autism spectrum disorders

BACKGROUND

Previous behavioural and neuroimaging studies of emotion processing in autistic spectrum disorder (ASD) have focused on the use of facial stimuli. To date, however, no studies have examined emotion processing in autism across a broad range of social signals.

METHOD

This study addressed this issue by investigating emotion processing in a group of 23 adults with ASD and 23 age- and gender-matched controls. Recognition of basic emotions ('happiness', 'sadness', 'anger', disgust' and 'fear') was assessed from facial, body movement and vocal stimuli. The ability to make social judgements (such as approachability) from facial stimuli was also investigated.

RESULTS

Significant deficits in emotion recognition were found in the ASD group relative to the control group across all stimulus domains (faces, body movements and voices). These deficits were seen across a range of emotions. The ASD group were also impaired in making social judgements compared to the control group and this correlated with impairments in basic emotion recognition.

CONCLUSIONS

This study demonstrates that there are significant and broad-ranging deficits in emotion processing in ASD present across a range of stimulus domains and in the auditory and visual modality; they cannot therefore be accounted for simply in terms of impairments in face processing or in the visual modality alone. These results identify a core deficit affecting the processing of a wide range of emotional information in ASD, which contributes to the impairments in social function seen in people with this condition.

Dysfunctions in brain networks supporting empathy: an fMRI study in adults with autism spectrum disorders

The present study aimed at identifying dysfunctions in brain networks that may underlie disturbed empathic behavior in autism spectrum disorders (ASD). During functional magnetic resonance imaging, subjects were asked to identify the emotional state observed in a facial stimulus (other-task) or to evaluate their own emotional response (self-task). Behaviorally, ASD subjects performed equally to the control group during the other-task, but showed less emotionally congruent responses in the self-task. Activations in brain regions related to theory of mind were observed in both groups. Activations of the medial prefrontal cortex (MPFC) were located in dorsal subregions in ASD subjects and in ventral areas in control subjects. During the self-task, ASD subjects activated an additional network of frontal and inferior temporal areas. Frontal areas previously associated with the human mirror system were activated in both tasks in control subjects, while ASD subjects recruited these areas during the self-task only. Activations in the ventral MPFC may provide the basis for one's "emotional bond" with other persons' emotions. Such atypical patterns of activation may underlie disturbed empathy in individuals with ASD. Subjects with ASD may use an atypical cognitive strategy to gain access to their own emotional state in response to other people's emotions.

Brain perfusion SPECT and EEG findings in children with autism spectrum disorders and medically intractable epilepsy

OBJECTIVE

We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both autism spectrum disorders (ASD) and medically intractable epilepsy.

METHODS

Fifteen children aged 4-16 years underwent multimodal examinations (MRI, interictal and/or ictal ECD-SPECT, EEG and MEG) to investigate their indications for surgical treatment. All children were diagnosed with ASD according to DSM-IV criteria and intractable epilepsy. Despite medical treatment for more than a year, all experienced at least one seizure per month. All had no underlying basic disorders. Each SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). The relationship between the eZIS pattern and EEG abnormalities or clinical symptoms was investigated.

RESULTS

All children showed focal abnormal patterns on eZIS and focal spikes on EEG. In all children, eZIS revealed a mixed hypoperfusion pattern, especially in the prefrontal cortex, medial frontal cortex, anterior cingulate cortex, medial parietal cortex, and/or anterior temporal cortex. In seven of 12 children who underwent interictal SPECT studies, areas of hypoperfusion were related to the focus observed on EEG; in six children, the focal EEG spikes represented areas of hyperperfusion. The children were divided into two groups according to the main type of hypoperfusion patterns seen on eZIS; medial-cingulate type and temporal type. No significant relationship was observed between the areas of hypoperfusion and clinical symptoms. eZIS showed the epileptic focus clearly on ictal SPECT.

CONCLUSIONS

SPECT was useful to detect the abnormal brain region not only in searching for the epileptic focus but also in assessing the low or high functioning region of the brain.

Abnormal functional connectivity of default mode sub-networks in autism spectrum disorder patients

Autism spectrum disorders (ASDs) are characterized by deficits in social and communication processes. Recent data suggest that altered functional connectivity (FC), i.e. synchronous brain activity, might contribute to these deficits. Of specific interest is the FC integrity of the default mode network (DMN), a network active during passive resting states and cognitive processes related to social deficits seen in ASD, e.g. Theory of Mind. We investigated the role of altered FC of default mode sub-networks (DM-SNs) in 16 patients with high-functioning ASD compared to 16 matched healthy controls of short resting fMRI scans using independent component analysis (ICA). ICA is a multivariate data-driven approach that identifies temporally coherent networks, providing a natural measure of FC. Results show that compared to controls, patients showed decreased FC between the precuneus and medial prefrontal cortex/anterior cingulate cortex, DMN core areas, and other DM-SNs areas. FC magnitude in these regions inversely correlated with the severity of patients' social and communication deficits as measured by the Autism Diagnostic Observational Schedule and the Social Responsiveness Scale. Importantly, supplemental analyses suggest that these results were independent of treatment status. These results support the hypothesis that DM-SNs under-connectivity contributes to the core deficits seen in ASD. Moreover, these data provide further support for the use of data-driven analysis with resting-state data for illuminating neural systems that differ between groups. This approach seems especially well suited for populations where compliance with and performance of active tasks might be a challenge, as it requires minimal cooperation.

Communication, interventions, and scientific advances in autism: a commentary

Autism spectrum disorders (ASD) affect approximately 1 in 150 children across the U.S., and are characterized by abnormal social actions, language difficulties, repetitive or restrictive behaviors, and special interests. ASD include autism (autistic disorder), Asperger Syndrome, and Pervasive Developmental Disorder not otherwise specified (PDD-NOS or atypical autism). High-functioning individuals may communicate with moderate-to-high language skills, although difficulties in social skills may result in communication deficits. Low-functioning individuals may have severe deficiencies in language, resulting in poor communication between the individual and others. Behavioral intervention programs have been developed for ASD, and are frequently adjusted to accommodate specific individual needs. Many of these programs are school-based and aim to support the child in the development of their skills, for use outside the classroom with family and friends. Strides are being made in understanding the factors contributing to the development of ASD, particularly the genetic contributions that may underlie these disorders. Mutant mouse models provide powerful research tools to investigate the genetic factors associated with ASD and its co-morbid disorders. In support, the BTBR T+tf/J mouse strain incorporates ASD-like social and communication deficits and high levels of repetitive behaviors. This commentary briefly reviews the reciprocal relationship between observations made during evidence-based behavioral interventions of high- versus low-functioning children with ASD and the accumulating body of research in autism, including animal studies and basic research models. This reciprocity is one of the hallmarks of the scientific method, such that research may inform behavioral treatments, and observations made during treatment may inform subsequent research.

Autism spectrum traits in the typical population predict structure and function in the posterior superior temporal sulcus

Autism spectrum disorders (ASDs) are typically characterized by impaired social interaction and communication, narrow interests, and repetitive behaviors. The heterogeneity in the severity of these characteristics across individuals with ASD has led some researchers to suggest that these disorders form a continuum which extends into the general, or “typical,” population, and there is growing evidence that the extent to which typical adults display autistic traits, as measured using the autism-spectrum quotient (AQ), predicts performance on behavioral tasks that are impaired in ASD. Here, we show that variation in autism spectrum traits is related to cortical structure and function within the typical population. Voxel-based morphometry showed that increased AQ scores were associated with decreased white matter volume in the posterior superior temporal sulcus (pSTS), a region important in processing socially relevant stimuli and associated with structural and functional impairments in ASD. In addition, AQ was correlated with the extent of cortical deactivation of an adjacent area of pSTS during a Stroop task relative to rest, reflecting variation in resting state function. The results provide evidence that autism spectrum characteristics are reflected in neural structure and function across the typical (non-ASD) population.

Unraveling the paradox of the autistic self

Paradoxically, individuals with autism spectrum conditions have been characterized as both impaired in self-referential cognitive processing, yet also egocentric. How can the self in autism be both 'absent' (i.e., impaired self-referential cognition), yet 'all too present' (i.e., egocentric)? In this paper, we first review evidence in support of both claims. Second, we highlight new evidence illustrating atypical function of neural systems underlying self-representation in autism. We suggest that egocentrism and impaired self-referential cognition are not independent phenomena. Instead, both egocentrism and impaired self-referential cognition in autism can be resolved as expressions of one common mechanism linked to the atypical function of neural circuitry coding for self-relevant information. We discuss how autism provides a unique window into the neurodevelopmental mechanisms enabling a critical developmental transition in self-awareness. This transition involves a dual understanding that one is similar to, yet distinct from others. The neural and cognitive basis of this developmental transition is central to understanding the development of social cognition as well as the paradox of the autistic self and its relation to social impairment in autism. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

Exploring motor system contributions to the perception of social information: Evidence from EEG activity in the mu/alpha frequency range

Putative contributions of a human mirror neuron system (hMNS) to the perception of social information have been assessed by measuring the suppression of EEG oscillations in the mu/alpha (8-12 Hz), beta (15-25 Hz) and low-gamma (25-25 Hz) ranges while participants processed social information revealed by point-light displays of human motion. Identical dynamic displays were presented and participants were instructed to distinguish the intention, the emotion, or the gender of a moving image of a person, while they performed an adapted odd-ball task. Relative to a baseline presenting a nonbiological but meaningful motion display, all three biological motion conditions reduced the EEG amplitude in the mu/alpha and beta ranges, but not in the low-gamma range. Suppression was larger in the intention than in the emotion and gender conditions, with no difference between the latter two. Moreover, the suppression in the intention condition was negatively correlated with an accepted measure of empathy (EQ), revealing that participants high in empathy scores manifested less suppression. For intention and emotion the suppression was larger at occipital than at central sites, suggesting that factors other than motor system were in play while processing social information embedded in the motion of point-light displays.

Atypical development of white matter microstructure in adolescents with autism spectrum disorders

Diffusion tensor imaging (DTI) studies in adolescents with autism spectrum disorders (ASD) indicate aberrant neurodevelopment of frontal white matter (WM), potentially underlying abnormal social cognition and communication in ASD. Here, we further use tract-based spatial statistics (TBSS) to examine the developmental change of WM skeleton (i.e., the most compact whole-brain WM) during adolescence in ASD. This whole-brain DTI used TBSS measures fractional anisotropy (FA) and longitudinal and radial diffusivities in fifty adolescents, 25 ASD and 25 controls. Results show that adolescents with ASD versus controls had significantly reduced FA in the right posterior limb of internal capsule (increased radial diffusivity distally and reduced longitudinal diffusivity centrally). Adolescents with ASD versus controls (covarying for age and IQ) had significantly greater FA in the frontal lobe (reduced radial diffusivity), right cingulate gyrus (reduced radial diffusivity), bilateral insula (reduced radial diffusivity and increased longitudinal diffusivity), right superior temporal gyrus (reduced radial diffusivity), and bilateral middle cerebellar peduncle (reduced radial diffusivity). Notably, a significant interaction with age by group was found in the right paracentral lobule and bilateral superior frontal gyrus as indicated by an age-related FA gain in the controls whilst an age-related FA loss in the ASD. To our knowledge, this is the first study to use TBSS to examine WM in individuals with ASD. Our findings indicate that the frontal lobe exhibits abnormal WM microstructure as well as an aberrant neurodevelopment during adolescence in ASD, which support the frontal disconnectivity theory of autism.

Inverse effects of oxytocin on attributing mental activity to others in depressed and healthy subjects: a double-blind placebo controlled FMRI study

BACKGROUND

Oxytocin is a stress-attenuating and pro-social neuropeptide. To date, no study has looked at the effects of oxytocin in modulating brain activity in depressed individuals nor attempted to correlate this activity with attribution of mental activity in others.

METHOD

We enrolled 10 unmedicated depressed adults and 10 matched healthy controls in a crossover, double blind placebo controlled fMRI 40 i.u. intra-nasal oxytocin study (20 i.u. per nostril). Each subject performed reading the mind in the eyes task (RMET) before and after inhalation of oxytocin or placebo control for a total of 80 scans.

RESULTS

Before oxytocin administration, RMET engaged the medial and lateral prefrontal cortex, amygdala, insula and associative areas. Depressed subjects showed increased anterior ventral activation for the RMET minus gender identification contrast whereas matched controls showed increased dorsal and frontal activity. Compared to placebo, oxytocin in depressed subjects showed increased activity in the superior middle frontal gyrus and insula, while controls exhibited more activity in ventral regions. Oxytocin also led to inverse effects in reaction times on attribution task between groups, with controls getting faster and depressed individuals slower to respond.

CONCLUSION

Depression is associated with increased paralimbic activity during emotional mental attribution of others, appearing to be distinctly modulated by oxytocin when compared to healthy controls. Further studies are needed to explore long-term exposure to pro-social neuropeptides on mood in depressed populations and assess their clinical relevance.

Revisiting the strange stories: revealing mentalizing impairments in autism

A test of advanced theory of mind (ToM), first introduced by F. Happé (1994), was adapted for children (mental, human, animal, and nature stories plus unlinked sentences). These materials were closely matched for difficulty and were presented to forty-five 7- to 12-year-olds with autism and 27 control children. Children with autism who showed ToM impairment on independent tests performed significantly more poorly than controls solely on the mental, human, and animal stories with greatest impairment on the former and least on the latter. Thus, a mentalizing deficit may affect understanding of biologic agents even when this does not explicitly require understanding others' mental states.

Theory of mind in borderline and cluster-C personality disorder

Borderline Personality Disorder (BPD) is associated with interpersonal problems, such as intense, unstable relationships and fears of abandonment. It has been hypothesized that deficits in social cognitive capacities explain these difficulties. One important aspect of social cognition is theory of mind (ToM)-the capacity to infer others' mental state. We tested ToM capacities with Happé's advanced ToM-test in 16 BPD patients, 16 Cluster-C PD patient controls, and 28 nonpatients. Social reasoning (WAIS Picture Arrangement), general intelligence, and current mood were also assessed. With and without controlling for intelligence, social reasoning, and mood, no evidence for deficits in ToM in BPD patients was found. In fact, both Cluster B and Cluster C patient groups tended to show generally superior performance to the nonpatients on the subscales of Happé ToM-test. All tests correlated similarly with intelligence in the 3 groups. These findings do not support the hypothesis that BPD patients have inferior theory of mind capacities.

Differential effects on white-matter systems in high-functioning autism and Asperger's syndrome

BACKGROUND

Whether autism spectrum maps onto a spectrum of brain abnormalities and whether Asperger's syndrome (ASP) is distinct from high-functioning autism (HFA) are debated. White-matter maldevelopment is associated with autism and disconnectivity theories of autism are compelling. However, it is unknown whether children with ASP and HFA have distinct white-matter abnormalities.

METHOD

Voxel-based morphometry mapped white-matter volumes across the whole brain in 91 children. Thirty-six had autism spectrum disorder. A history of delay in phrase speech defined half with HFA; those without delay formed the ASP group. The rest were typically developing children, balanced for age, IQ, gender, maternal language and ethnicity. White-matter volumes in HFA and ASP were compared and each contrasted with controls.

RESULTS

White-matter volumes around the basal ganglia were higher in the HFA group than ASP and higher in both autism groups than controls. Compared with controls, children with HFA had less frontal and corpus callosal white matter in the left hemisphere; those with ASP had less frontal and corpus callosal white matter in the right hemisphere with more white matter in the left parietal lobe.

CONCLUSIONS

HFA involved mainly left hemisphere white-matter systems; ASP affected predominantly right hemisphere white-matter systems. The impact of HFA on basal ganglia white matter was greater than ASP. This implies that aetiological factors and management options for autism spectrum disorders may be distinct. History of language acquisition is a potentially valuable marker to refine our search for causes and treatments in autism spectrum.

Cultural effects on the neural basis of theory of mind

"Theory of mind" has been described as the ability to attribute and understand other people's desires and intentions as distinct from one's own. It has been found to develop as early as between 3 and 4 years old, with precursor abilities possibly developing much earlier. There has been debate about the extent to which the developmental trajectory of theory of mind may differ across cultures or language systems. Although very few neuroimaging studies have directly compared different groups from different culture and language systems, across studies of a number of cultural/language groups have been used to explore the neural correlates of theory of mind. A summary of these findings suggests that there may be both universal and culture or language-specific neural correlates related to theory of mind. These studies, while still preliminary in many ways, illustrate the importance of taking into account the cultural background of participants. Furthermore these results suggest that there may be important cultural influence on theory of mind and the neural correlates associated with this ability.

The human mirror neuron system in a population with deficient self-awareness: an fMRI study in alexithymia

The mirror neuron system (MNS) is considered crucial for human imitation and language learning and provides the basis for the development of empathy and mentalizing. Alexithymia (ALEX), which refers to deficiencies in the self-awareness of emotional states, has been reported to be associated with poor ability in various aspects of social cognition such as mentalizing, cognitive empathy, and perspective-taking. Using functional magnetic resonance imaging (fMRI), we measured the hemodynamic signal to examine whether there are functional differences in the MNS activity between participants with ALEX (n = 16) and without ALEX (n = 13), in response to a classic MNS task (i.e., the observation of video clips depicting goal-directed hand movements). Both groups showed increased neural activity in the premotor and the parietal cortices during observation of hand actions. However, activation was greater for the ALEX group than the non-ALEX group. Furthermore, activation in the left premotor area was negatively correlated with perspective-taking ability as assessed with the interpersonal reactivity index. The signal in parietal cortices was negatively correlated with cognitive facets assessed by the stress coping inventory and positively correlated with the neuroticism scale from the NEO five factor personality scale. In addition, in the ALEX group, activation in the right superior parietal region showed a positive correlation with the severity of ALEX as measured by a structured interview. These results suggest that the stronger MNS-related neural response in individuals scoring high on ALEX is associated with their insufficient self-other differentiation.

Impaired prefrontal hemodynamic maturation in autism and unaffected siblings

Background

Dysfunctions of the prefrontal cortex have been previously reported in individuals with autism spectrum disorders (ASD). Previous studies reported that first-degree relatives of individuals with ASD show atypical brain activity during tasks associated with social function. However, developmental changes in prefrontal dysfunction in ASD and genetic influences on the phenomena remain unclear. In the present study, we investigated the change in hemoglobin concentration in the prefrontal cortex as measured with near-infrared spectroscopy, in children and adults with ASD during the letter fluency test. Moreover, to clarify the genetic influences on developmental changes in the prefrontal dysfunction in ASD, unaffected siblings of the ASD participants were also assessed.

Methodology/Principal Findings

Study participants included 27 individuals with high-functioning ASD, age- and IQ-matched 24 healthy non-affected siblings, and 27 unrelated healthy controls aged 5 to 39 years. The relative concentration of hemoglobin ([Hb]) in the prefrontal cortex was measured during the letter fluency task. For children, neither the [oxy-Hb] change during the task nor task performances differed significantly among three groups. For adults, the [oxy-Hb] increases during the task were significantly smaller in the bilateral prefrontal cortex in ASD than those in control subjects, although task performances were similar. In the adult siblings the [oxy-Hb] change was intermediate between those in controls and ASDs.

Conclusion/Significance

Although indirectly due to a cross-sectional design, the results of this study indicate altered age-related change of prefrontal activity during executive processing in ASD. This is a first near-infrared spectroscopy study that implies alteration in the age-related changes of prefrontal activity in ASD and genetic influences on the phenomena.

Neural mechanisms of empathy in adolescents with autism spectrum disorder and their fathers

A deficit in empathy has been repeatedly described in individuals with autism spectrum disorder (ASD) and also, albeit less markedly, in their unaffected relatives. Here, we aimed to investigate the neural mechanisms of empathy in ASD, and to explore familial contributions to empathy correlates. Using functional magnetic resonance imaging, 15 boys with ASD, 11 fathers of adolescents with ASD, and two control groups comparable for age and IQ (n=15 typically developing boys and their fathers (n=9)) were investigated during an empathy task. Emotional faces were presented and participants were either asked to infer the emotional state from the face (other-task) or to judge their own emotional response to the face (self-task). When attributing emotions to self and other, the ASD group showed diminished fusiform gyrus activation compared to controls. Neural activity in the fusiform gyrus was inversely related to social deficits in ASD subjects. Moreover, when ASD subjects inferred their own emotional response to faces, they showed less congruent reactions and inferior frontal gyrus activity was decreased. Although fathers of ASD children scored higher on a self-rating scale for autistic symptoms compared to control fathers, their task performance was unimpaired. However, neurally, fathers of affected children also showed reduced fusiform gyrus activation when inferring others' emotions. Shared abnormalities in fusiform gyrus activation in affected adolescents and first-degree relatives suggest that this dysfunction constitutes a fundamental deviation in ASD. Moreover, the findings provide evidence that both aberrant neural face and mirroring mechanisms are implicated in empathy impairments in ASD.

The Medial Prefrontal Cortex and Integration in Autism

This article offers a unifying theoretical interpretation of known abnormalities in people with autism spectrum disorders (ASDs) in four psychological domains, namely emotion, memory, sensation-perception, and motor skills. It proposes that in all four domains three levels of processing can be identified: a basic level, an integrative level, and a “logical” or higher-order level. It also notes that in typically developing people, there is evidence that the integrative level is subserved by subregions of the medial prefrontal cortex. The major argument of the article is to propose and argue that the integrative level in all four domains is responsible for common atypicalities in people with ASDs.

Autism: research into causes and intervention

Autism spectrum conditions are neuro-developmental syndromes with strong heritability. Cognitive theories have had some success in explaining why the cluster of features should co-occur. Empathizing deficits have the potential to make sense of one triad of impairments (social difficulties, communication difficulties and imagining others' minds), and may have a brain basis in the amygdala and left medial frontal cortex. A strong systemizing drive may account for a distinct triad of strengths (good attention to detail, deep, narrow interests and islets of ability). The brain basis of systemizing is yet to be understood. Family genetics studies suggest that these same cognitive dimensions (reduced empathizing alongside a strong drive to systemize) may also characterize the 'broader phenotype' among first-degree relatives. Molecular genetic studies are underway and any candidate genes for autism will ultimately need to be tested in relation to the observed differences in the brain, cognition and behaviour. The ethics of genetic screening or gene therapy should be thought about well ahead of these becoming available, since there is by no means any consensus that these would be desirable given the wide range of phenotypic traits, not all of which are disabling. Future research will need to focus on evaluating the extent to which any form of intervention reduces the triad of impairments whilst supporting the triad of strengths.

What aspects of autism predispose to talent?

In this paper, we explore the question, why are striking special skills so much more common in autism spectrum conditions (ASC) than in other groups? Current cognitive accounts of ASC are briefly reviewed in relation to special skills. Difficulties in 'theory of mind' may contribute to originality in ASC, since individuals who do not automatically 'read other minds' may be better able to think outside prevailing fashions and popular theories. However, originality alone does not confer talent. Executive dysfunction has been suggested as the 'releasing' mechanism for special skills in ASC, but other groups with executive difficulties do not show raised incidence of talents. Detail-focused processing bias ('weak coherence', 'enhanced perceptual functioning') appears to be the most promising predisposing characteristic, or 'starting engine', for talent development. In support of this notion, we summarize data from a population-based twin study in which parents reported on their 8-year-olds' talents and their ASC-like traits. Across the whole sample, ASC-like traits, and specifically 'restricted and repetitive behaviours and interests' related to detail focus, were more pronounced in children reported to have talents outstripping older children. We suggest that detail-focused cognitive style predisposes to talent in savant domains in, and beyond, autism spectrum disorders.

Neuropsychological profile of autism and the broad autism phenotype

CONTEXT

Multiple articles describe a constellation of language, personality, and social-behavioral features present in relatives that mirror the symptom domains of autism, but are much milder in expression. Studies of this broad autism phenotype (BAP) may provide a potentially important complementary approach for detecting the genes causing autism and defining associated neural circuitry by identifying more refined phenotypes that can be measured quantitatively in both affected and unaffected individuals and that are tied to functioning in particular regions of the brain.

OBJECTIVE

To gain insight into neuropsychological features that index genetic liability to autism.

DESIGN

Case-control study.

SETTING

The general community.

PARTICIPANTS

Thirty-eight high-functioning individuals with autism and parents of autistic individuals, both with and without the BAP (n = 83), as well as control individuals.

MAIN OUTCOME MEASURES

A comprehensive battery of neuropsychological tasks assessing social cognition, executive function, and global vs local processing strategies (central coherence).

RESULTS

Both individuals with autism and parents with the BAP differed from controls on measures of social cognition, with performance in the other 2 domains being more similar to controls.

CONCLUSIONS

Data suggest that the social cognitive domain may be an important target for linking phenotype to cognitive process to brain structure in autism and may ultimately provide insight into the genes involved in autism.

Asperger's syndrome in adulthood

INTRODUCTION

Asperger's syndrome is one of the autism spectrum disorders. Affected individuals display considerably impaired capacity for social interaction, unusual special interests, and a tendency towards ritualized behavior.

METHODS

The etiology, symptoms, diagnosis, and treatment of Asperger's syndrome in adulthood are outlined on the basis of a selective literature review via Medline and information in relevant reference books. Furthermore, the authors report their personal experience at a special clinic for adults.

RESULTS

Asperger's syndrome in adulthood can be diagnosed by thorough anamnesis, heteroanamnesis-with emphasis on childhood-and painstaking clinical examination. The considerable psychosocial impairments affect the patients' professional, social, and private lives. The precise etiology is still unknown, but a multifactorial origin with genetic, neurobiological, and psychosocial components appears probable. Although no specific, empirically tested treatment concepts have yet been established, psychotherapeutic elements (structuring and directive interventions) seem to be helpful, together with pharmacotherapy-if indicated-in the presence of comorbidity.

CONCLUSIONS

Asperger's syndrome should be included in the differential diagnosis of adults who display the corresponding symptoms. The etiopathogenesis and treatment of Asperger's syndrome in adulthood should be further investigated.

Functional brain correlates of social and nonsocial processes in autism spectrum disorders: an activation likelihood estimation meta-analysis

BACKGROUND

Functional neuroimaging studies of autism spectrum disorders (ASD) have examined social and nonsocial paradigms, although rarely in the same study. Here, we provide an objective, unbiased survey of functional brain abnormalities in ASD, related to both social and nonsocial processing.

METHODS

We conducted two separate voxel-wise activation likelihood estimation meta-analyses of 39 functional neuroimaging studies consisting of 24 studies examining social processes (e.g., theory of mind, face perception) and 15 studies examining nonsocial processes (e.g., attention control, working memory). Voxel-wise significance threshold was p<.05, corrected by false discovery rate.

RESULTS

Compared with neurotypical control (NC) subjects, ASD showed greater likelihood of hypoactivation in two medial wall regions: perigenual anterior cingulate cortex (ACC) in social tasks only and dorsal ACC in nonsocial studies. Further, right anterior insula, recently linked to social cognition, was more likely to be hypoactivated in ASD in the analyses of social studies. In nonsocial studies, group comparisons showed greater likelihood of activation for the ASD group in the rostral ACC region that is typically suppressed during attentionally demanding tasks.

CONCLUSIONS

Despite substantial heterogeneity of tasks, the rapidly increasing functional imaging literature showed ASD-related patterns of hypofunction and aberrant activation that depended on the specific cognitive domain, i.e., social versus nonsocial. These results provide a basis for targeted extensions of these findings with younger subjects and a range of paradigms, including analyses of default mode network regulation in ASD.

Asperger syndrome

Asperger syndrome (AS) is a chronic neurodevelopmental disorder of social interaction, communication, and a restricted range of behaviors or interests. Although not generally associated with intellectual disability, the severe social disability and, in many cases, associated mental health and other medical problems, result in disability throughout life. The diagnosis is often delayed, sometimes into adulthood, which is unfortunate because there are now a range of interventions available, and the current evidence supports intervention starting as early in childhood as possible. The aim of this review is to present a description of AS, an up to date synopsis of the literature pertaining to its etiology, co-morbidity and intervention options, and a discussion of current nosological controversies.

The Role of the Theory-of-Mind Cortical Network in the Comprehension of Narratives

Narrative comprehension rests on the ability to understand the intentions and perceptions of various agents in a story who interact with respect to some goal or problem. Reasoning about the state of mind of another person, real or fictional, has been referred to as Theory of Mind processing. While Theory of Mind Processing was first postulated prior to the existence of neuroimaging research, fMRI studies make it possible to characterize this processing in some detail. We propose that narrative comprehension makes use of some of the neural substrate of Theory of Mind reasoning, evoking what is referred to as a protagonist perspective network. The main cortical components of this protagonist-based network are the dorsomedial prefrontal cortex and the right temporo-parietal junction. The article discusses how these two cortical centers interact in narrative comprehension but still play distinguishable roles, and how the interaction between the two centers is disrupted in individuals with autism.

Atypical modulation of cognitive control by arousal in autism

We examined the effects of viewing high-arousal pictures on regional brain activations elicited by a cognitive control task in participants with high-functioning autism and neurotypical controls. Specifically, using event-related functional magnetic resonance imaging, we assessed the effects of brief presentations of highly arousing pictures (i.e., both very pleasant and very unpleasant) on the processing of stimuli requiring cognitive control. Similar to previous findings, when stimuli with high cognitive control demands were preceded by low-arousal pictures, individuals with autism demonstrated regional brain activations that were comparable to neurotypical control individuals. When the presentation of the cognitive control stimuli was preceded by high-arousal pictures, however, the control group was characterized by relatively greater activation in the right lateral midfrontal cortex in response to cognitive control stimuli. In contrast, preceding high-arousal stimuli did not modulate activity elicited in this region by cognitive control stimuli in the autism group. Differential modulation of right lateral midfrontal activation by high-arousal stimuli in autism is consistent with the "inefficiency model" of brain functioning in autism spectrum disorders, and contributes to a growing body of evidence that autism may be characterized by anomalous sensitivity of cognitive control brain regions to social-emotional context.

Individual differences in theory of mind ability in middle childhood and links with verbal ability and autistic traits: a twin study

Identifying the causal processes involved in theory of mind (ToM) development during childhood is an important goal for social neuroscience. This study aimed to investigate, for the first time, the extent to which individual differences in ToM are influenced by genes and environment in middle childhood, and to assess how ToM is linked to autistic-like behaviors and verbal ability. Over 600 9-year-old twin pairs from a subsample of the Twins Early Development Study were assessed on an advanced test of ToM and on verbal ability. Parents, teachers, and the children themselves provided ratings of the twins' autistic traits (social impairments, communication impairments, and restricted repetitive behaviors and interests), using an abbreviated version of the Childhood Asperger Syndrome Test. Autistic traits, particularly communication impairments, significantly predicted ToM performance. Verbal ability showed the strongest phenotypic association with ToM. Twin model-fitting was employed to investigate the causes of this association. Much of the variation in ToM ability and in verbal ability was explained by environmental influences, with modest heritabilities for each, but their association was almost fully explained by shared genetic effects. The possible neural basis underlying this association is discussed.

Perspective-taking as part of narrative comprehension: a functional MRI study

During narrative comprehension, readers understand the emotions of the protagonist by taking the perspective of the character, which is an essential component of empathy. Spatial perspective-taking is crucial to understanding the standpoints and perceptions of others, and gives clues as to what the protagonist knows. As a default, a "here and now" point-of-view is adopted to make sense of the narrative. If the protagonist is in a different location while an event takes place ("there and now"), in order to comprehend the narrative the reader must take an allocentric perspective, which places greater demands on spatial perspective-taking. Utilizing this phenomenon, we evaluated the neural substrates of perspective-taking in emotional narrative comprehension using functional MRI in 18 normal adults. The subjects read short stories followed by a target sentence, which described an event that might evoke an emotional response in the protagonist if the character were present. The stories involved a scenario in which the character was either present at the same location ("here and now") or at a distant location ("there and now") during the event. The "there and now" scenario activated the posterior cingulate cortex and the right temporo-parietal junction more prominently than the "here and now" condition. In contrast to the control tasks, both scenarios activated the well-known mentalizing network including the dorsomedial prefrontal cortex, temporal pole, posterior cingulate cortex and temporo-parietal junction. Along with the mentalizing network, the posterior cingulate cortex and the right temporo-parietal junction are involved in spatial perspective-taking during emotional narrative comprehension.

From loci to networks and back again: anomalies in the study of autism

Recent developments in functional imaging as well as the emergence of new anatomical imaging techniques suited for the study of white matter have shifted investigational paradigms from a localized to a more holistic network approach. Aside from detecting local activity, functional MRI can be applied to the study of connectivity. However, the concept of "functional connectivity" remains broad, and specific designs and analyses may affect the results. In addition, connectivity cannot be viewed in isolation. Rather, from a developmental perspective, connectivity and local cortical architecture are intimately related. Therefore, combined approaches examining local organization and connectivity are the most promising avenues for elucidating disturbances of neurofunctional organization in developmental disorders. Here this approach is illustrated via data obtained from autism research that suggest impaired local cortical architecture and reduced long-range connectivity between cerebral regions.

Integration of emotional and cognitive aspects of theory of mind in schizophrenia and its relation to prefrontal neurocognitive performance

INTRODUCTION

There is substantial evidence that patients with schizophrenia present with impaired Theory of Mind (ToM). Whereas previous studies have focused on general ToM abilities, the present study is aimed at testing the underlying behavioural and neurocognitive mechanisms of the impaired integration of affective and cognitive aspects of ToM (the integration of emotional information with mentalising) in patients with schizophrenia.

METHODS

Twenty-six patients with schizophrenia and 35 healthy controls were tested on two ToM tasks involving the integration of affective and cognitive ToM abilities: "Faux Pas" and "reading the mind in the eyes" tasks. To assess the neurocognitive bases of impaired ToM, the ID/ED test (intradimensional/extradimensional shifting test from the CANTAB) was administered.

RESULTS

Patients performed poorly on both the cognitive-affective integration ToM tasks and the ID/ED task as compared to controls. Furthermore, patients' ToM scores were selectively correlated with the reversal trials, which are believed to be associated with orbitofrontal functioning. In addition, more than 50% of the variance in recognising and understanding Faux Pas could be explained by patients' symptomatology. Performance on orbitofrontal related tasks was correlated with subjects' Faux Pas scores in the patients group, but not in the healthy control group.

CONCLUSIONS

Schizophrenic patients appear to have considerable impairment in affective and cognitive ToM integration, which may be related to orbitofrontal dysfunction. These results are in line with previous findings regarding empathy and the importance of the orbitofrontal area in the integration of cognition and affect.

Hyper-connectivity and hyper-plasticity in the medial prefrontal cortex in the valproic Acid animal model of autism

The prefrontal cortex has been extensively implicated in autism to explain deficits in executive and other higher-order functions related to cognition, language, sociability and emotion. The possible changes at the level of the neuronal microcircuit are however not known. We studied microcircuit alterations in the prefrontal cortex in the valproic acid rat model of autism and found that the layer 5 pyramidal neurons are connected to significantly more neighbouring neurons than in controls. These excitatory connections are more plastic displaying enhanced long-term potentiation of the strength of synapses. The microcircuit alterations found in the prefrontal cortex are therefore similar to the alterations previously found in the somatosensory cortex. Hyper-connectivity and hyper-plasticity in the prefrontal cortex implies hyper-functionality of one of the highest order processing regions in the brain, and stands in contrast to the hypo-functionality that is normally proposed in this region to explain some of the autistic symptoms. We propose that a number of deficits in autism such as sociability, attention, multi-tasking and repetitive behaviours, should be re-interpreted in the light of a hyper-functional prefrontal cortex.

The purpose and neurobiology of theory of mind functions

Theory of Mind (ToM) refers to a cognitive process which allows an individual to "place him/herself" in the other person's "mind," so as to comprehend the latter's cognitive and emotional status, so as to predict his/her behavior and emotional response to a particular situation. ToM is necessary for everyday interaction among individuals and accounts for such human traits as empathy, compassion, and deceit. It is also particularly important in the relationship between a healer and his or her client, as well as in the God-human relationship. Recent research in the area of neurosciences has identified a specific brain "system" responsible for ToM, as well as described how these functions may be affected in certain neuropsychiatric conditions. In this article, we discuss the definition and neurobiological substrate of ToM. In addition, we discuss the cognitive steps important to achieve an "accurate" theory of mind, its relevance to "self-knowledge," and its limitations. We also review some of the data concerning abnormalities and "distortion" of ToM in neuropsychiatric disorders and aberrant human behavior.