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

Assessing Frontal Lobe Function on Verbal Fluency and Emotion Recall in Autism Spectrum Disorder by fNIRS

This study applied the functional near-infrared spectroscopy (fNIRS) to investigate frontal activity in autism when performing verbal fluency test and emotion recall task. We recruited 32 autistic adults without intellectual disability and 30 typically-developing controls (TDC). Prefrontal hemodynamic changes were evaluated by fNIRS when the participants performed the verbal fluency test and emotion recall task. fNIRS signals in the prefrontal cortex were compared between autism and TDC. Compared to TDC, autistic adults showed comparable performance on the verbal fluency test but exhibited lower frontal activity on the vegetable category. In the verbal fluency test, left frontal activity in TDC significantly increased in the vegetable category (vs. fruit category). In the emotion recall task, left frontal activity increased significantly in TDC when recalling emotional (vs. neutral) events. This increase of left frontal activity on the more difficult works was not found in autism. Similarly, brain activities were related to test performance only in TDC but not in autism. In addition, more severe social deficits were associated with lower frontal activity when recalling emotional events, independent of autism diagnosis. Findings suggested reduced frontal activity in autism, as compared to TDC, when performing verbal fluency tests. The reduction of left frontal activation in verbal fluency test and emotion recall tasks might reflect on the social deficits of the individual. The fNIRS may potentially be applied in assessing frontal lobe function in autism and social deficits in general population. Trial registration number: NCT04010409.

The macaque medial prefrontal cortex simultaneously represents self and others' reward prediction error

Learning the causal structures of social environments involves predicting significant events (e.g., rewards) and detecting prediction errors for each agent. Whether the brain can simultaneously compute reward prediction errors for self (S-RPE) and others (O-RPE), and which neurons are responsible, is unclear. Here, we condition two monkeys with identical visual stimuli predicting different reward outcomes and find that dorsomedial prefrontal neurons represent both S-RPE and O-RPE simultaneously. Neuronal signatures of RPE are agent and sign specific, forming distinct populations for positive and negative S-RPE and O-RPE. A linear decoder trained on neurons encoding O-RPE, but not S-RPE, successfully discriminates RPE. Further investigation identifies coexisting actual reward and prediction confirmation signals for others. These results highlight the presence of neuronal mechanisms in the primate brain that update the value of environmental stimuli simultaneously for oneself and others, enabling primates to comprehend the causal structure of the world from the perspective of others.

Effect of Emotional Valence on Emotion Recognition in Adolescents with Autism Spectrum Disorder

This study investigated how emotional valence of a perceived emotional state impacted performance on the Reading the Mind in the Eyes task (RMET) in adolescents with autism spectrum disorder (ASD) and typically developing (TD) controls. Valence of items on the RMET, Adult (RMET-A) and Child (RMET-C) versions, was first classified in a survey of 113 medical students. Adolescents with ASD (N = 33) and TD adolescents (N = 30) were administered both RMET versions. Individuals with ASD made more errors than TD controls on positive and negative, but not neutral, valence items. The difference in performance was accentuated on the RMET-A compared to the RMET-C. Both emotional valence and complexity of language contribute to RMET performance in individuals with ASD.

Connectivity differences between inferior frontal gyrus and mentalizing network in autism as compared to developmental coordination disorder and non-autistic youth

Prior studies have compared neural connectivity during mentalizing tasks in autism (ASD) to non-autistic individuals and found reduced connectivity between the inferior frontal gyrus (IFG) and mentalizing regions. However, given that the IFG is involved in motor processing, and about 80% of autistic individuals have motor-related difficulties, it is necessary to explore if these differences are specific to ASD or instead similar across other developmental motor disorders, such as developmental coordination disorder (DCD). Participants (29 ASD, 20 DCD, 31 typically developing [TD]; ages 8-17) completed a mentalizing task in the fMRI scanner, where they were asked to think about why someone was performing an action. Results indicated that the ASD group, as compared to both TD and DCD groups, showed significant functional connectivity differences when mentalizing about other's actions. The left IFG seed revealed ASD connectivity differences with the: bilateral temporoparietal junction (TPJ), left insular cortex, and bilateral dorsolateral prefrontal cortex (DLPFC). Connectivity differences using the right IFG seed revealed ASD differences in the: left insula, and right DLPFC. These results indicate that connectivity differences between the IFG, mentalizing regions, emotion and motor processing regions are specific to ASD and not a result of potentially co-occurring motor differences.

Examining whether adults with autism spectrum disorder encounter multiple problems in theory of mind: a study based on meta-analysis

Theory of mind (ToM) represents a complex ability, while persons with autism spectrum disorder (ASD) encounter difficulties in the processing of ToM. The present ToM-focused studies on adults with ASD report inconsistent results, possibly owing to the differences between tasks. For instance, different ToM-related tasks involve different cognitive abilities, but the development of these cognitive abilities is different among adults with ASD, thereby leading to different behaviors by the same individual with ASD in different tasks. Therefore, it is of vital significance to explore the potential reasons for inconsistencies in the existing studies based on the task classification perspective. Hence, this study primarily reviews the existing ToM tasks used in studies on adults with ASD; afterward, based on the forms and characteristics of the task, the current ToM tasks are classified into four categories-reading comprehension, perceptual scene comprehension, comprehensive scene comprehension , and self-other processing. Subsequently, a meta-analysis is undertaken to determine the difference in each ToM task category between the ASD group and the typically developing (TD) group. As a result, 110 research papers (including 3,205 adults with ASD and 3,675 TD adults) that fulfilled the stated criteria are examined in this study. The study findings suggest that adults with ASD demonstrate worse performance in terms of all four ToM task categories as compared to TD adults. Furthermore, compared with tasks of self-other processing and perceptual scene comprehension, adults with ASD perform worse in reading comprehension and comprehensive scene comprehension. This shows that the differences between tasks may exert a potential influence on the study results. Future studies should focus on different abilities involved in ToM processing and the choice of ToM tasks, in order to elucidate the critical problems of ToM in adults with ASD.

Narcolepsy and emotions: Is there a place for a theory of mind approach?

Narcolepsy type 1 is a central disorder of hypersomnolence characterized by excessive daytime sleepiness, rapid eye movement sleep-related manifestations, and cataplexy. In the current literature there is general agreement regarding neural correlates of Narcolepsy type 1 that appear to be related to anatomical and functional abnormalities in the hypothalamic region. In the last two decades, researchers shed light on the neurological bases of cataplexy by focusing on the neurobiological correlates of emotions. Although the results of these studies differ, they all point to an impairment in the amygdala and hypothalamus functions that are known to be involved in emotional processing, suggesting an impairment in this domain in narcoleptic patients. Indeed, despite heterogeneous results, several studies showed that narcoleptic patients differed from healthy controls in processing emotional stimuli. From a behavioral point of view, these findings suggest that alterations in emotional processing may be driven, at least in part, by compensatory strategies to avoid or reduce the frequency of cataplexy attacks. Surprisingly, the only study exploring in NT1 the behavioural performances in emotional facial recognition found no differences between NT1 adults and controls. We hypothesize that narcoleptic patients may present an alteration in a more complex socio-cognitive ability that is related to emotional processing, namely Theory of Mind. This review aims to investigate the literature supporting this hypothesis and to propose possible future developments on this topic.

Functional near-infrared spectroscopy is a useful tool for multi-perspective psychobiological study of neurophysiological correlates of parenting behaviour

The quality of the relationship between caregiver and child has long-term effects on the cognitive and socio-emotional development of children. A process involved in human parenting is the bio-behavioural synchrony that occurs between the partners in the relationship during interaction. Through interaction, bio-behavioural synchronicity allows the adaptation of the physiological systems of the parent to those of the child and promotes the positive development and modelling of the child's social brain. The role of bio-behavioural synchrony in building social bonds could be investigated using functional near-infrared spectroscopy (fNIRS). In this paper we have (a) highlighted the importance of the quality of the caregiver-child relationship for the child's cognitive and socio-emotional development, as well as the relevance of infantile stimuli in the activation of parenting behaviour; (b) discussed the tools used in the study of the neurophysiological substrates of the parental response; (c) proposed fNIRS as a particularly suitable tool for the study of parental responses; and (d) underlined the need for a multi-systemic psychobiological approach to understand the mechanisms that regulate caregiver-child interactions and their bio-behavioural synchrony. We propose to adopt a multi-system psychobiological approach to the study of parental behaviour and social interaction.

When humor is a matter of heart: effects on emotional state and Interbeat Interval

Previous studies demonstrated that exposure to humor has beneficial effects on psychological well-being. In the present work, we investigated the behavioral and psychophysiological effects of different types of humor on psychological well-being and on the performance during the execution of a stressful cognitive task. To this aim, we examined the behavioral and psychophysiological effects of ToM humorous and Slapstick humorous comic strips before and after executing a stressful cognitive task. We hypothesized that only slapstick humor could reduce the level of anxiety, increase positive affect and improve performance on the cognitive task. Our findings revealed that, at a specific point in time, exposure to ToM Humor and No Humor strips were associated with lower IBI (higher HR, increase in cardiac recruitment) than slapstick humor. This result suggests that humor involving ToM abilities and No Humor strips elicited a greater cognitive engagement level than slapstick humor. Moreover, in an exploratory analysis we found a positive correlation between cardiac deactivation during the exposure to slapstick Humor and individual empathy scores, suggesting that the empathy skills might influence cardiac recruitment and the level of cognitive engagement during the exposure to humorous material.

Attention for Emotion-How Young Adults With Neurodevelopmental Disorders Look at Facial Expressions of Affect

While Autism Spectrum Disorder (ASD), Attention-Deficit/Hyperactivity Disorder (ADHD) and Schizophrenia (SCZ) differ in many clinically relevant features such as symptomatology and course, they may also share genetic underpinnings, affective problems, deviancies in social interactions, and are all characterized by some kind of cognitive impairment. This situation calls for a joint investigation of the specifics of cognitive (dys-)functions of the three disorders. Such endeavor should focus, among other domains, on the inter-section of processing cognitive, affective and social information that is crucial in effective real-life interactions and can be accomplished when attentional preferences for human facial expressions of emotions is studied. To that end, attention to facial expressions of basic emotions was examined in young adults with ASD, ADHD, or SCZ in the present study. The three clinical groups were compared with an age-matched group of typically-developing participants (TD) during the free contemplation of five different facial emotions presented simultaneously, by varying identities, through the registration of eye movements. We showed, that dwell times and fixation counts differed for the different emotions in TD and in a highly similar way in ADHD. Patients with ASD differed from TD by showing a stronger differentiation between emotions and partially different attentional preferences. In contrast, the SCZ group showed an overall more restricted scanning behavior and a lack of differentiation between emotions. The ADHD group, showed an emotion-specific gazing pattern that was highly similar to that of controls. Thus, by analyzing eye movements, we were able to differentiate three different viewing patterns that allowed us to distinguish between the three clinical groups. This outcome suggests that attention for emotion may not tap into common pathophysiological processes and argues for a multi-dimensional approach to the grouping of disorders with neurodevelopmental etiology.

Prefrontal-amygdalar oscillations related to social behavior in mice

The medial prefrontal cortex and amygdala are involved in the regulation of social behavior and associated with psychiatric diseases but their detailed neurophysiological mechanisms at a network level remain unclear. We recorded local field potentials (LFPs) from the dorsal medial prefrontal cortex (dmPFC) and basolateral amygdala (BLA) while male mice engaged on social behavior. We found that in wild-type mice, both the dmPFC and BLA increased 4–7 Hz oscillation power and decreased 30–60 Hz power when they needed to attend to another target mouse. In mouse models with reduced social interactions, dmPFC 4–7 Hz power further increased especially when they exhibited social avoidance behavior. In contrast, dmPFC and BLA decreased 4–7 Hz power when wild-type mice socially approached a target mouse. Frequency-specific optogenetic manipulations replicating social approach-related LFP patterns restored social interaction behavior in socially deficient mice. These results demonstrate a neurophysiological substrate of the prefrontal cortex and amygdala related to social behavior and provide a unified pathophysiological understanding of neuronal population dynamics underlying social behavioral deficits.

Positron Emission Tomography in the Neuroimaging of Autism Spectrum Disorder: A Review

Autism spectrum disorder (ASD) is a basket term for neurodevelopmental disorders characterized by marked impairments in social interactions, repetitive and stereotypical behaviors, and restricted interests and activities. Subtypes include (A) disorders with known genetic abnormalities including fragile X syndrome, Rett syndrome, and tuberous sclerosis and (B) idiopathic ASD, conditions with unknown etiologies. Positron emission tomography (PET) is a molecular imaging technology that can be utilized in vivo for dynamic and quantitative research, and is a valuable tool for exploring pathophysiological mechanisms, evaluating therapeutic efficacy, and accelerating drug development in ASD. Recently, several imaging studies on ASD have been published and physiological changes during ASD progression was disclosed by PET. This paper reviews the specific radioligands for PET imaging of critical biomarkers in ASD, and summarizes and discusses the similar and different discoveries in outcomes of previous studies. It is of great importance to identify general physiological changes in cerebral glucose metabolism, cerebral blood flow perfusion, abnormalities in neurotransmitter systems, and inflammation in the central nervous system in ASD, which may provide excellent points for further ASD research.

Incongruence effects in cross-modal emotional processing in autistic traits: An fMRI study

In everyday life, emotional information is often conveyed by both the face and the voice. Consequently, information presented by one source can alter the way in which information from the other source is perceived, leading to emotional incongruence. Here, we used functional magnetic resonance imaging (fMRI) to examine neutral correlates of two different types of emotional incongruence in audiovisual processing, namely incongruence of emotion-valence and incongruence of emotion-presence. Participants were in two groups, one group with a low Autism Quotient score (LAQ) and one with a high score (HAQ). Each participant experienced emotional (happy, fearful) or neutral faces or voices while concurrently being exposed to emotional (happy, fearful) or neutral voices or faces. They were instructed to attend to either the visual or auditory track. The incongruence effect of emotion-valence was characterized by activation in a wide range of brain regions in both hemispheres involving the inferior frontal gyrus, cuneus, superior temporal gyrus, and middle frontal gyrus. The incongruence effect of emotion-presence was characterized by activation in a set of temporal and occipital regions in both hemispheres, including the middle occipital gyrus, middle temporal gyrus and inferior temporal gyrus. In addition, the present study identified greater recruitment of the right inferior parietal lobule in perceiving audio-visual emotional expressions in HAQ individuals, as compared to the LAQ individuals. Depending on face or voice-to-be attended, different patterns of emotional incongruence were found between the two groups. Specifically, the HAQ group tend to show more incidental processing to visual information whilst the LAQ group tend to show more incidental processing to auditory information during the crossmodal emotional incongruence decoding. These differences might be attributed to different attentional demands and different processing strategies between the two groups.

Inhibitory Theta Burst Stimulation Highlights the Role of Left aIPS and Right TPJ during Complementary and Imitative Human-Avatar Interactions in Cooperative and Competitive Scenarios

Competitive and cooperative interactions are based on anticipation or synchronization with the partner's actions. Both forms of interaction may either require performing imitative or complementary movements with respect to those performed by our partner. We explored how parietal regions involved in the control of imitative behavior (temporo-parietal junction, TPJ), goal coding and visuo-motor integration (anterior intraparietal sulcus, aIPS) contribute to the execution of imitative and complementary movements during cooperative and competitive interactions. To this aim, we delivered off-line non-invasive inhibitory brain stimulation to healthy individuals' left aIPS and right TPJ before they were asked to reach and grasp an object together with a virtual partner by either performing imitative or complementary interactions. In different blocks, participants were asked to compete or cooperate with the virtual partner that varied its behavior according to cooperative or competitive contexts. Left aIPS and right TPJ inhibition impaired individuals' performance (i.e., synchrony in cooperative task and anticipation in competition) during complementary and imitative interactions, respectively, in both cooperative and competitive contexts, indicating that aIPS and TPJ inhibition affects own-other action integration and action imitation (that are different in complementary vs imitative interactions) more than action synchronization or anticipation (that are different in cooperative vs competitive contexts).

The Role of the Medial Prefrontal Cortex in Moderating Neural Representations of Self and Other in Primates

As a frontal node in the primate social brain, the medial prefrontal cortex (MPFC) plays a critical role in coordinating one's own behavior with respect to that of others. Current literature demonstrates that single neurons in the MPFC encode behavior-related variables such as intentions, actions, and rewards, specifically for self and other, and that the MPFC comes into play when reflecting upon oneself and others. The social moderator account of MPFC function can explain maladaptive social cognition in people with autism spectrum disorder, which tips the balance in favor of self-centered perspectives rather than taking into consideration the perspective of others. Several strands of evidence suggest a hypothesis that the MPFC represents different other mental models, depending on the context at hand, to better predict others' emotions and behaviors. This hypothesis also accounts for aberrant MPFC activity in autistic individuals while they are mentalizing others.

The neural basis for mental state attribution: A voxel-based lesion mapping study

The ability to infer other persons' mental states, "Theory of Mind" (ToM), is a key function of social cognition and is needed when interpreting the intention of others. ToM is associated with a network of functionally related regions, with reportedly key prominent hubs located in the dorsolateral prefrontal cortex (dlPFC) and the temporoparietal junction (TPJ). The involvement of (mainly the right) TPJ in ToM is based primarily on functional imaging studies that provide correlational evidence for brain-behavior associations. In this lesion study, we test whether certain brain areas are necessary for intact ToM performance. We investigated individuals with penetrating traumatic brain injury (n = 170) and healthy matched controls (n = 30) using voxel-based lesion-symptom mapping (VLSM) and by measuring the impact of a given lesion on white matter disconnections. ToM performance was compared between five patient groups based on lesion location: right TPJ, left TPJ, right dlPFC, left dlPFC, and other lesion, as well as healthy controls. The only group to present with lower ToM abilities was the one with lesions in the right dlPFC. Similarly, VLSM analysis revealed a main cluster in the right frontal middle gyrus and a secondary cluster in the left inferior parietal gyrus. Last, we found that disconnection of the left inferior longitudinal fasciculus and right superior longitudinal fasciculus were associated with poor ToM performance. This study highlights the importance of lesion studies in complementing functional neuroimaging findings and supports the assertion that the right dlPFC is a key region mediating mental state attribution.

mRNA expression of the P5 ATPase ATP13A4 is increased in Broca's area from subjects with schizophrenia

Objectives: ATPase Type 13A4 (ATP13A4) is a cation-transporting, P₅-type ATPase that has been implicated in neurodevelopmental disorders. Our recent microarray study reported a significant increase in ATP13A4 mRNA levels in Brodmann's area (BA) nine in subjects with schizophrenia compared to controls. Following this discovery we have sought to determine whether ATP13A4 expression was altered in other regions of the CNS that are affected in schizophrenia.Methods: Quantitative PCR was used to measure the levels of ATP13A4 in BA 44 and BA 8, collected post-mortem, from 30 subjects with schizophrenia and 30 non-psychiatric control subjects. To address the potential confound of antipsychotic medication on our data, qPCR was used to measure Atp13a4 levels in rats treated with haloperidol.Results: There was a 2.6-fold increase in ATP13A4 expression (P < 0.001) in BB 44 from subjects with schizophrenia. Results from BA 8 were less clear. ATP13A4 levels were not affected by antipsychotic treatment.Conclusions: Our findings suggest ATP13A4 is involved in the pathophysiology of schizophrenia. The increase in ATP13A4 contrasts genetic studies that report ATP13A4 gene deletions in patients with schizophrenia. A greater understanding of the function of ATP13A4 in the CNS may lead to improved treatment strategies for the symptoms of schizophrenia.

Annual Research Review: Looking back to look forward - changes in the concept of autism and implications for future research

The concept of autism is a significant contribution from child psychiatry that has entered wider culture and public consciousness, and has evolved significantly over the last four decades. Taking a rather personal retrospective, reflecting on our own time in autism research, this review explores changes in the concept of autism and the implications of these for future research. We focus on seven major changes in how autism is thought of, operationalised, and recognised: (1) from a narrow definition to wide diagnostic criteria; (2) from a rare to a relatively common condition, although probably still under-recognised in women; (3) from something affecting children, to a lifelong condition; (4) from something discreet and distinct, to a dimensional view; (5) from one thing to many 'autisms', and a compound or 'fractionable' condition; (6) from a focus on 'pure' autism, to recognition that complexity and comorbidity is the norm; and finally, (7) from conceptualising autism purely as a 'developmental disorder', to recognising a neurodiversity perspective, operationalised in participatory research models. We conclude with some challenges for the field and suggestions for areas currently neglected in autism research.

Electrophysiological indexes of ToM and non-ToM humor in healthy adults

The cognitive processes involved in humor comprehension were analyzed by directly comparing the time course of brain activity associated with the perception of slapstick humor and that associated with the comprehension of humor requiring theory of mind (ToM). Four different comic strips (strips containing humorous scenes that required ToM, non-ToM humorous strips, non-humorous semantically coherent strips and non-humorous semantically incoherent strips) were presented to participants, while their EEG response was recorded. Results showed that both of the humorous comic strips and the semantically incongruent strip elicited an N400 effect, suggesting similar cognitive mechanisms underlying the processing of incongruent and humorous comic strips. The results also showed that the humorous ToM strips elicited a frontal late positive (LP) response, possibly reflecting the active deployment of ToM abilities such as perspective-taking and empathy that allow for the resolution and interpretation of apparently incongruent situations. In addition, the LP response was positively correlated with ratings of perceived amusement as well as individual empathy scores, suggesting that the increased LP response to ToM humorous strips reflects the combined activation of neural mechanisms involved in the experience of amusement and ToM abilities. Overall, humor comprehension appears to demand distinct cognitive steps such as the detection of incongruent semantic components, the construction of semantic coherence, and the appreciation of humoristic elements such as maladaptive emotional reactions. Our results show that the deployment of these distinct cognitive steps is at least partially dependent on individual empathic abilities.

Hypothesis: The highly folded brain surface might be structured and located so as to facilitate inter-brain synchronization

We integrate recent findings from neuro-anatomy, electroencephalography, quantum biology and social/neurodevelopment to propose that the brain surface might be specialised for communication with other brains.

Ground breaking, but still small-scale, research has demonstrated that human brains can act in synchrony and detect the brain activity of other human brains. Group aggregation, in all species, maximises community support and safety but does not depend on verbal or visual interaction. The morphology of the brain’s outermost layers, across a wide range of species, exhibits a highly folded fractal structure that is likely to maximise exchange at the surface: in humans, a reduced brain surface area is associated with disorders of social communication. The brain sits in a vulnerable exposed location where it is prone to damage, rather than being housed in a central location such as within the ribcage.

These observations have led us to the hypothesis that the brain surface might be specialised for interacting with other brains at its surface, allowing synchronous non-verbal interaction. To our knowledge, this has not previously been proposed or investigated.

The Protracted Maturation of Associative Layer IIIC Pyramidal Neurons in the Human Prefrontal Cortex During Childhood: A Major Role in Cognitive Development and Selective Alteration in Autism

The human specific cognitive shift starts around the age of 2 years with the onset of self-awareness, and continues with extraordinary increase in cognitive capacities during early childhood. Diffuse changes in functional connectivity in children aged 2-6 years indicate an increase in the capacity of cortical network. Interestingly, structural network complexity does not increase during this time and, thus, it is likely to be induced by selective maturation of a specific neuronal subclass. Here, we provide an overview of a subclass of cortico-cortical neurons, the associative layer IIIC pyramids of the human prefrontal cortex. Their local axonal collaterals are in control of the prefrontal cortico-cortical output, while their long projections modulate inter-areal processing. In this way, layer IIIC pyramids are the major integrative element of cortical processing, and changes in their connectivity patterns will affect global cortical functioning. Layer IIIC neurons have a unique pattern of dendritic maturation. In contrast to other classes of principal neurons, they undergo an additional phase of extensive dendritic growth during early childhood, and show characteristic molecular changes. Taken together, circuits associated with layer IIIC neurons have the most protracted period of developmental plasticity. This unique feature is advanced but also provides a window of opportunity for pathological events to disrupt normal formation of cognitive circuits involving layer IIIC neurons. In this manuscript, we discuss how disrupted dendritic and axonal maturation of layer IIIC neurons may lead into global cortical disconnectivity, affecting development of complex communication and social abilities. We also propose a model that developmentally dictated incorporation of layer IIIC neurons into maturing cortico-cortical circuits between 2 to 6 years will reveal a previous (perinatal) lesion affecting other classes of principal neurons. This "disclosure" of pre-existing functionally silent lesions of other neuronal classes induced by development of layer IIIC associative neurons, or their direct alteration, could be found in different forms of autism spectrum disorders. Understanding the gene-environment interaction in shaping cognitive microcircuitries may be fundamental for developing rehabilitation and prevention strategies in autism spectrum and other cognitive disorders.

Identifying specific prefrontal neurons that contribute to autism-associated abnormalities in physiology and social behavior

Functional imaging and gene expression studies both implicate the medial prefrontal cortex (mPFC), particularly deep-layer projection neurons, as a potential locus for autism pathology. Here, we explored how specific deep-layer prefrontal neurons contribute to abnormal physiology and behavior in mouse models of autism. First, we find that across three etiologically distinct models-in utero valproic acid (VPA) exposure, CNTNAP2 knockout and FMR1 knockout-layer 5 subcortically projecting (SC) neurons consistently exhibit reduced input resistance and action potential firing. To explore how altered SC neuron physiology might impact behavior, we took advantage of the fact that in deep layers of the mPFC, dopamine D2 receptors (D2Rs) are mainly expressed by SC neurons, and used D2-Cre mice to label D2R+ neurons for calcium imaging or optogenetics. We found that social exploration preferentially recruits mPFC D2R+ cells, but that this recruitment is attenuated in VPA-exposed mice. Stimulating mPFC D2R+ neurons disrupts normal social interaction. Conversely, inhibiting these cells enhances social behavior in VPA-exposed mice. Importantly, this effect was not reproduced by nonspecifically inhibiting mPFC neurons in VPA-exposed mice, or by inhibiting D2R+ neurons in wild-type mice. These findings suggest that multiple forms of autism may alter the physiology of specific deep-layer prefrontal neurons that project to subcortical targets. Furthermore, a highly overlapping population-prefrontal D2R+ neurons-plays an important role in both normal and abnormal social behavior, such that targeting these cells can elicit potentially therapeutic effects.

Aberrant Neural Activation Underlying Idiom Comprehension in Korean Children with High Functioning Autism Spectrum Disorder

PURPOSE

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication impairments and repetitive behaviors or restricted interests. Impaired pragmatic language comprehension is a universal feature in individuals with ASD. However, the underlying neural basis of pragmatic language is poorly understood. In the present study, we examined neural activation patterns associated with impaired pragmatic language comprehension in ASD, compared to typically developing children (TDC).

MATERIALS AND METHODS

Functional magnetic resonance imaging (fMRI) was applied to 15 children with ASD and 18 TDC using the Korean pragmatic language task.

RESULTS

Children with ASD were less accurate than TDC at comprehending idioms, particularly when they were required to interpret idioms with mismatched images (mismatched condition). Children with ASD also showed different patterns of neural activity than TDC in all three conditions (neutral, matched, and mismatched). Specifically, children with ASD showed decreased activation in the right inferior frontal gyrus (IFG) (Brodmann area 47) in the mismatched condition, compared with TDC (IFG; t(31)=3.17, p<0.001).

CONCLUSION

These results suggest that children with ASD face difficulties in comprehending pragmatic expressions and apply different pragmatic language processes at the neural level.

Microbiota influence the development of the brain and behaviors in C57BL/6J mice

We investigated the contributions of commensal bacteria to brain structural maturation by magnetic resonance imaging and behavioral tests in four and 12 weeks old C57BL/6J specific pathogen free (SPF) and germ free (GF) mice. SPF mice had increased volumes and fractional anisotropy in major gray and white matter areas and higher levels of myelination in total brain, major white and grey matter structures at either four or 12 weeks of age, demonstrating better brain maturation and organization. In open field test, SPF mice had better mobility and were less anxious than GF at four weeks. In Morris water maze, SPF mice demonstrated better spatial and learning memory than GF mice at 12 weeks. In fear conditioning, SPF mice had better contextual memory than GF mice at 12 weeks. In three chamber social test, SPF mice demonstrated better social novelty than GF mice at 12 weeks. Our data demonstrate numerous significant differences in morphological brain organization and behaviors between SPF and GF mice. This suggests that commensal bacteria are necessary for normal morphological development and maturation in the grey and white matter of the brain regions with implications for behavioral outcomes such as locomotion and cognitive functions.

False Belief Reasoning in Adults with and without Autistic Spectrum Disorder: Similarities and Differences

A central diagnostic criteria for autism spectrum disorder (ASD) is the qualitative impairment in reciprocal social interaction and a prominent hypotheses that tried to explain this impairment is the Theory of Mind (ToM) deficit hypotheses. On a behavioral level the critical test for having a ToM, the understanding of false beliefs (FB), is often used for testing ToM abilities in individuals with ASD. Investigating the neural underpinnings several neuroimaging studies revealed a network of areas involved in FB reasoning in neurotypical individuals. For ASD individuals the neural correlates of false belief processing are largely unknown. Using functional magnetic resonance imaging and an adapted unexpected transfer task, that makes it possible to distinguish between the computation of diverging beliefs and the selection of a belief-associated response, we investigated a group of adult high-functioning individuals with ASD (N = 15) and an age and IQ matched group of neurotypical adults (NT; N = 15). On the behavioral level we found no group differences. On the neural level, results were two-fold: In the story phase, in which participants had to compute whether the character's belief is congruent or incongruent to their own belief, there were no differences between neurotypical participants and those diagnosed with ASD. But, in the subsequent question phase, participants with ASD showed increased activity in the bilateral anterior prefrontal cortex, the left posterior frontal cortex, the left superior temporal gyrus, and the left temporoparietal area. These results suggest that during the story phase in which the participants processed observable actions the neural correlates do not differ between adult individuals with ASD and NT individuals. But in the question phase in which participants had to infer an unobservable mental state results revealed neural differences between the two groups. Possibly, these subtle neural processing differences may contribute to the fact that adult ASD individuals are able to master explicit false belief tasks but fail to apply their strategies during everyday social interaction.

Neuroanatomical and neurofunctional markers of social cognition in autism spectrum disorder

Social impairments in autism spectrum disorder (ASD), a hallmark feature of its diagnosis, may underlie specific neural signatures that can aid in differentiating between those with and without ASD. To assess common and consistent patterns of differences in brain responses underlying social cognition in ASD, this study applied an activation likelihood estimation (ALE) meta-analysis to results from 50 neuroimaging studies of social cognition in children and adults with ASD. In addition, the group ALE clusters of activation obtained from this was used as a social brain mask to perform surface-based cortical morphometry (SBM) in an empirical structural MRI dataset collected from 55 ASD and 60 typically developing (TD) control participants. Overall, the ALE meta-analysis revealed consistent differences in activation in the posterior superior temporal sulcus at the temporoparietal junction, middle frontal gyrus, fusiform face area (FFA), inferior frontal gyrus (IFG), amygdala, insula, and cingulate cortex between ASD and TD individuals. SBM analysis showed alterations in the thickness, volume, and surface area in individuals with ASD in STS, insula, and FFA. Increased cortical thickness was found in individuals with ASD, the IFG. The results of this study provide functional and anatomical bases of social cognition abnormalities in ASD by identifying common signatures from a large pool of neuroimaging studies. These findings provide new insights into the quest for a neuroimaging-based marker for ASD. Hum Brain Mapp 37:3957-3978, 2016. © 2016 Wiley Periodicals, Inc.

Affective and cognitive theory of mind abilities in youth with borderline personality disorder or major depressive disorder

BACKGROUND

Theory of mind (ToM) is an important social cognitive ability that has been investigated in BPD, with inconsistent findings indicating impaired, comparable, and enhanced ToM in BPD. This study aimed to clarify and extend previous findings by investigating affective and cognitive ToM abilities in youth early in the course of BPD, by including a clinical comparison group of youth with major depressive disorder (MDD).

METHODS

Female participants aged 15-24 years diagnosed with BPD (n = 41) or MDD (n = 37) completed the Reading the Mind in the Eyes Test (RMET) and Happé's Cartoon Task, measures of affective and cognitive dimensions of ToM, respectively.

RESULTS

The BPD group performed significantly worse than the MDD group on the affective ToM task, even after controlling for age, intelligence and depressive symptoms. Results for cognitive ToM were not significantly different.

CONCLUSIONS

Finding of poorer performance on a measure of affective ToM, in BPD youth, relative to youth with MDD early in the course of BPD suggest a developmental failure of sociocognitive abilities needed for mentalising and which are theorised as giving rise to core features of BPD. Future research should employ more naturalistic paradigms to study social cognition and should assess individuals even earlier in the course of BPD.

Measuring Theory of Mind in Adults with Autism Spectrum Disorder

Deficits in Theory of Mind (ToM)-the ability to interpret others' beliefs, intentions and emotions-undermine the ability of individuals with Autism Spectrum Disorder (ASD) to interact in socially normative ways. This study provides psychometric data for the Adult-Theory of Mind (A-ToM) measure using video-scenarios based in part on Happé's (Instructions for theory of mind story task, 1999) Strange Stories test. The final items discriminated IQ-matched adults with ASD from controls on the social but not the physical items. Additional validity data included a two-component principal components solution, correlations with existing ToM scales, and the absence of correlations with self-report measures of empathy and social anxiety (not requiring inferences about the intent of others). The expected group differences in ToM were accompanied by marked variability in the ASD sample.

The neural basis of understanding the expression of the emotions in man and animals

Humans cannot help but attribute human emotions to non-human animals. Although such attributions are often regarded as gratuitous anthropomorphisms and held apart from the attributions humans make about each other's internal states, they may be the product of a general mechanism for flexibly interpreting adaptive behavior. To examine this, we used functional magnetic resonance imaging (fMRI) in humans to compare the neural mechanisms associated with attributing emotions to humans and non-human animal behavior. Although undergoing fMRI, participants first passively observed the facial displays of human, non-human primate and domestic dogs, and subsequently judged the acceptability of emotional (e.g. 'annoyed') and facial descriptions (e.g. 'baring teeth') for the same images. For all targets, emotion attributions selectively activated regions in prefrontal and anterior temporal cortices associated with causal explanation in prior studies. These regions were similarly activated by both human and non-human targets even during the passive observation task; moreover, the degree of neural similarity was dependent on participants' self-reported beliefs in the mental capacities of non-human animals. These results encourage a non-anthropocentric view of emotion understanding, one that treats the idea that animals have emotions as no more gratuitous than the idea that humans other than ourselves do.

The Structural and Functional Organization of Cognition

This article proposes that what have been historically and contemporarily defined as different domains of human cognition are served by one of four functionally- and structurally-distinct areas of the prefrontal cortex (PFC). Their contributions to human intelligence are as follows: (a) BA9, enables our emotional intelligence, engaging the psychosocial domain; (b) BA47, enables our practical intelligence, engaging the material domain; (c) BA46 (or BA46-9/46), enables our abstract intelligence, engaging the hypothetical domain; and (d) BA10, enables our temporal intelligence, engaging in planning within any of the other three domains. Given their unique contribution to human cognition, it is proposed that these areas be called the, social (BA9), material (BA47), abstract (BA46-9/46) and temporal (BA10) mind. The evidence that BA47 participates strongly in verbal and gestural communication suggests that language evolved primarily as a consequence of the extreme selective pressure for practicality; an observation supported by the functional connectivity between BA47 and orbital areas that negatively reinforce lying. It is further proposed that the abstract mind (BA46-9/46) is the primary seat of metacognition charged with creating adaptive behavioral strategies by generating higher-order concepts (hypotheses) from lower-order concepts originating from the other three domains of cognition.

Patterns of Atypical Functional Connectivity and Behavioral Links in Autism Differ Between Default, Salience, and Executive Networks

Autism spectrum disorder (ASD) is characterized by atypical brain network organization, but findings have been inconsistent. While methodological and maturational factors have been considered, the network specificity of connectivity abnormalities remains incompletely understood. We investigated intrinsic functional connectivity (iFC) for four "core" functional networks-default-mode (DMN), salience (SN), and left (lECN) and right executive control (rECN). Resting-state functional MRI data from 75 children and adolescents (37 ASD, 38 typically developing [TD]) were included. Functional connectivity within and between networks was analyzed for regions of interest (ROIs) and whole brain, compared between groups, and correlated with behavioral scores. ROI analyses showed overconnectivity (ASD > TD), especially between DMN and ECN. Whole-brain results were mixed. While predominant overconnectivity was found for DMN (posterior cingulate seed) and rECN (right inferior parietal seed), predominant underconnectivity was found for SN (right anterior insula seed) and lECN (left inferior parietal seed). In the ASD group, reduced SN integrity was associated with sensory and sociocommunicative symptoms. In conclusion, atypical connectivity in ASD is network-specific, ranging from extensive overconnectivity (DMN, rECN) to extensive underconnectivity (SN, lECN). Links between iFC and behavior differed between groups. Core symptomatology in the ASD group was predominantly related to connectivity within the salience network.

Differential sensory fMRI signatures in autism and schizophrenia: Analysis of amplitude and trial-to-trial variability

Autism and schizophrenia share multiple phenotypic and genotypic markers, and there is ongoing debate regarding the relationship of these two disorders. To examine whether cortical dynamics are similar across these disorders, we directly compared fMRI responses to visual, somatosensory and auditory stimuli in adults with autism (N=15), with schizophrenia (N=15), and matched controls (N=15). All participants completed a one-back letter detection task presented at fixation (to control attention) while task-irrelevant sensory stimulation was delivered to the different modalities. We focused specifically on the response amplitudes and the variability in sensory fMRI responses of the two groups, given the evidence of greater trial-to-trial variability in adults with autism. Both autism and schizophrenia individuals showed weaker signal-to-noise ratios (SNR) in sensory-evoked responses compared to controls (d>0.42), but for different reasons. For the autism group, the fMRI response amplitudes were indistinguishable from controls but were more variable trial-to-trial (d=0.47). For the schizophrenia group, response amplitudes were smaller compared to autism (d=0.44) and control groups (d=0.74), but were not significantly more variable (d<0.29). These differential group profiles suggest (1) that greater trial-to-trial variability in cortical responses may be specific to autism and is not a defining characteristic of schizophrenia, and (2) that blunted response amplitudes may be characteristic of schizophrenia. The relationship between the amplitude and the variability of cortical activity might serve as a specific signature differentiating these neurodevelopmental disorders. Identifying the neural basis of these responses and their relationship to the underlying genetic bases may substantially enlighten the understanding of both disorders.

Proposal of auxiliary diagnosis index for autism spectrum disorder using near-infrared spectroscopy

Lack of a diagnostic index is a problem that needs to be overcome in the diagnosis of autism spectrum disorder (ASD), because this problem prevents an objective assessment based on biomarkers. This paper describes the development of a diagnostic index for ASD using near-infrared spectroscopy (NIRS). We investigated continuous prefrontal hemodynamic changes depending on reciprocal disposition of working memory and nonworking memory tasks using two-channel NIRS. NIRS signals in the prefrontal cortex were compared between high-functioning ASD subjects ([Formula: see text]) and typically developed (TD) subjects ([Formula: see text]). The brain activities of the TD subjects were related to experimental design. These results were not confirmed in brain activities of ASD subjects, although the task performance rate was almost equivalent. The brain activities of TD subjects and ASD subjects were evaluated using a weighted separability (WS) index obtained from the feature phase of oxy-hemoglobin and its differential value. Calculation of the [Formula: see text]-test (TD subject versus ASD subject) confirmed that WS was significant. This result showed that the proposed index was useful for evaluation of the brain activity of ASD subjects.

Attention and Working Memory in Adolescents with Autism Spectrum Disorder: A Functional MRI Study

The present study examined attention and memory load-dependent differences in the brain activation and deactivation patterns between adolescents with autism spectrum disorders (ASDs) and typically developing (TD) controls using functional magnetic resonance imaging. Attentional (0-back) and working memory (WM; 2-back) processing and load differences (0 vs. 2-back) were analysed. WM-related areas activated and default mode network deactivated normally in ASDs as a function of task load. ASDs performed the attentional 0-back task similarly to TD controls but showed increased deactivation in cerebellum and right temporal cortical areas and weaker activation in other cerebellar areas. Increasing task load resulted in multiple responses in ASDs compared to TD and in inadequate modulation of brain activity in right insula, primary somatosensory, motor and auditory cortices. The changes during attentional task may reflect compensatory mechanisms enabling normal behavioral performance. The inadequate memory load-dependent modulation of activity suggests diminished compensatory potential in ASD.

Social Cognition and the Prefrontal Cortex

Social cognitive neuroscience is a rapidly emerging field that utilizes cognitive neuroscientific techniques (e.g., lesion studies, neuroimaging) to address concepts traditionally in the social psychological realm (e.g., attitudes, stereotypes). The purpose of this article is to review published neuroscientific and neuropsychological research into social cognition. The author focuses on the role of the prefrontal cortex in social behavior and presents a framework that provides cohesion of this research. The article proposes that this framework will be useful in guiding future social cognitive neuroscientific research.

Great Expectations: The Role of Rules in Guiding Pro-social Behaviour in Groups with High Versus Low Autistic Traits

Measuring autistic traits in the general population has proven sensitive for examining cognition. The present study extended this to pro-social behaviour, investigating the influence of expectations to help others. A novel task describing characters in need of help was administered to students scoring high versus low on the Autism-Spectrum Quotient. Scenarios had two variants, describing either a ‘clear-cut’ or ‘ambiguous’ social rule. Participants with high versus low autistic traits were less pro-social and sympathetic overall towards the characters. The groups’ ratings of characters’ expectations were comparable, but those with high autistic traits provided more rule-based rationales in the clear-cut condition. This pattern of relatively intact knowledge in the context of reduced pro-social behaviour has implications for social skill training programmes.

Being asked to tell an unpleasant truth about another person activates anterior insula and medial prefrontal cortex

"Truth" has been used as a baseline condition in several functional magnetic resonance imaging (fMRI) studies of deception. However, like deception, telling the truth is an inherently social construct, which requires consideration of another person's mental state, a phenomenon known as Theory of Mind. Using a novel ecological paradigm, we examined blood oxygenation level dependent (BOLD) responses during social and simple truth telling. Participants (n = 27) were randomly divided into two competing teams. Post-competition, each participant was scanned while evaluating performances from in-group and out-group members. Participants were asked to be honest and were told that their evaluations would be made public. We found increased BOLD responses in the medial prefrontal cortex, bilateral anterior insula and precuneus when participants were asked to tell social truths compared to simple truths about another person. At the behavioral level, participants were slower at responding to social compared to simple questions about another person. These findings suggest that telling the truth is a nuanced cognitive operation that is dependent on the degree of mentalizing. Importantly, we show that the cortical regions engaged by truth telling show a distinct pattern when the task requires social reasoning.

Theory-of-mind in individuals with Alström syndrome is related to executive functions, and verbal ability

Objective: This study focuses on cognitive prerequisites for the development of theory-of-mind (ToM), the ability to impute mental states to self and others in young adults with Alström syndrome (AS). AS is a rare and quite recently described recessively inherited ciliopathic disorder which causes progressive sensorineural hearing loss and juvenile blindness, as well as many other organ dysfunctions. Two cognitive abilities were considered; Phonological working memory (WM) and executive functions (EF), both of importance in speech development.

Methods: Ten individuals (18–37 years) diagnosed with AS, and 20 individuals with no known impairment matched for age, gender, and educational level participated. Sensory functions were measured. Information about motor functions and communicative skills was obtained from responses to a questionnaire. ToM was assessed using Happés strange stories, verbal ability by a vocabulary test, phonological WM by means of an auditory presented non-word serial recall task and EF by tests of updating and inhibition.

Results: The AS group performed at a significantly lower level than the control group in both the ToM task and the EF tasks. A significant correlation was observed between recall of non-words and EF in the AS group. Updating, but not inhibition, correlated significantly with verbal ability, whereas both updating and inhibition were significantly related to the ability to initiate and sustain communication. Poorer performance in the ToM and EF tasks were related to language perseverance and motor mannerisms.

Conclusion: The AS group displayed a delayed ToM as well as reduced phonological WM, EF, and verbal ability. A significant association between ToM and EF, suggests a compensatory role of EF. This association may reflect the importance of EF to perceive and process input from the social environment when the social interaction is challenged by dual sensory loss. We argue that limitations in EF capacity in individuals with AS, to some extent, may be related to early blindness and progressive hearing loss, but maybe also to gene specific abnormalities.