Major Depression and the Perception of Affective Instrumental and Expressive Gestures: An fMRI Investigation.

Major depressive disorder (MDD) is associated with biased perception of human movement. Gesture is important for communication and in this study we investigated neural correlates of gesture perception in MDD. We hypothesised different neural activity between individuals with MDD and typical individuals when viewing instrumental and expressive gestures that were negatively or positively valenced. Differences were expected in brain areas associated with gesture perception, including superior temporal, frontal, and emotion processing regions. We recruited 12 individuals with MDD and 12 typical controls matched on age, gender, and handedness. They viewed gestures displayed by stick figures while functional magnetic resonance imaging (fMRI) was performed. Results of a random effects three-way mixed ANOVA indicated that individuals with MDD had greater activity in the right claustrum compared to controls, regardless of gesture type or valence. Additionally, we observed main effects of gesture type and valence, regardless of group. Perceiving instrumental compared to expressive gestures was associated with greater activity in the left cuneus and left superior temporal gyrus, while perceiving negative compared to positive gestures was associated with greater activity in the right precuneus and right lingual gyrus. We also observed a two-way interaction between gesture type and valence in various brain regions.

Do distinct atypical cortical networks process biological motion information in adults with Autism Spectrum Disorders?

Whether people with Autism Spectrum Disorders (ASDs) have a specific deficit when processing biological motion has been a topic of much debate. We used psychophysical methods to determine individual behavioural thresholds in a point-light direction discrimination paradigm for a small but carefully matched groups of adults (N=10 per group) with and without ASDs. These thresholds were used to derive individual stimulus levels in an identical fMRI task, with the purpose of equalising task performance across all participants whilst inside the scanner. The results of this investigation show that despite comparable behavioural performance both inside and outside the scanner, the group with ASDs shows a different pattern of BOLD activation from the TD group in response to the same stimulus levels. Furthermore, connectivity analysis suggests that the main differences between the groups are that the TD group utilise a unitary network with information passing from temporal to parietal regions, whilst the ASD group utilise two distinct networks; one utilising motion sensitive areas and another utilising form selective areas. Furthermore, a temporal-parietal link that is present in the TD group is missing in the ASD group. We tentatively propose that these differences may occur due to early dysfunctional connectivity in the brains of people with ASDs, which to some extent is compensated for by rewiring in high functioning adults.

Online mentalising investigated with functional MRI.

For successful interpersonal communication, inferring intentions, goals or desires of others is highly advantageous. Increasingly, humans also interact with computers or robots. In this study, we sought to determine to what degree an interactive task, which involves receiving feedback from social partners that can be used to infer intent, engaged the medial prefrontal cortex, a region previously associated with Theory of Mind processes among others. Participants were scanned using fMRI as they played an adapted version of the Prisoner's Dilemma Game with alleged human and computer partners who were outside the scanner. The medial frontal cortex was activated when both human and computer partner were played, while the direct contrast revealed significantly stronger signal change during the human-human interaction. The results suggest a link between activity in the medial prefrontal cortex and the partner played in a mentalising task. This signal change was also present for to the computers partner. Implying agency or a will to non-human actors might be an innate human resource that could lead to an evolutionary advantage.

Are women better mindreaders? Sex differences in neural correlates of mentalizing detected with functional MRI.

BACKGROUND: The ability to mentalize, i.e. develop a Theory of Mind (ToM), enables us to anticipate and build a model of the thoughts, emotions and intentions of others. It has long been hypothesised that women differ from men in their mentalizing abilities. In the present fMRI study we examined the impact of (1) gender (women vs. men) and (2) game partner (human vs. computer) on ToM associated neural activity in the medial prefrontal cortex. Groups of men (n = 12) and women (n = 12) interacted in an iterated classical prisoner's dilemma forced choice situation with alleged human and computer partners who were outside the scanner. RESULTS: Both the conditions of playing against putative human as well as computer partners led to activity increases in mPFC, ACC and rTPJ, constituting the classic ToM network. However, mPFC/ACC activity was more pronounced when participants believed they were playing against the alleged human partner. Differences in the medial frontal lobe activation related to the sex of the participants could be demonstrated for the human partner > computer partner contrast. CONCLUSION: Our data demonstrate differences in medial prefrontal brain activation during a ToM task depending on both the gender of participants and the game partner.

A neuropsychological investigation into 'Theory of Mind' and enhanced risk of schizophrenia.

Theory of Mind (ToM) is the ability to correctly determine the intentions and behaviours of others. It is known that this capability is compromised in individuals with schizophrenia. It is has not been fully elucidated whether this observed phenomenon is of a state or trait nature. This study investigated whether ToM impairments could be linked to schizophrenia liability. A battery of ToM tests (the Hinting Task, a Self-Monitoring drawing task and cartoon picture stories) were used to compare healthy controls (n=13) with relatives of individuals with schizophrenia who had experienced psychotic symptoms (HR+, n=12) and those relatives who had not (HR-, n=13). All participants belonged to the Edinburgh High Risk Study. Significant group differences were seen on the Self-Monitoring and cartoon tasks for the HR+ group, particularly those who had experienced symptoms at or around the time of testing. The observed ToM deficits measured by this battery of ToM tasks appeared to be related to state effects rather than enhanced risk of schizophrenia.

A visual joke fMRI investigation into Theory of Mind and enhanced risk of schizophrenia.

Theory of Mind (ToM) or mentalizing is the ability of individuals to determine the intentions and behavior of others. This ability is known to be compromised in schizophrenia and has been shown to fluctuate with symptom severity. Neuropsychological investigations into relatives of individuals with schizophrenia have shown that some relatives also show a deficit in this area of social cognition. In order to address this state and trait issue, we investigated the performance of high-risk relatives of individuals with schizophrenia to those of a matched control group (n = 13) on a blocked design visual joke fMRI paradigm. The task involved looking at two sets of cartoon jokes, one set which required mentalizing abilities to understand the jokes and another set that did not require such abilities. Relatives were divided into two groups based on the presence (HR+, n = 12) or absence (HR-, n = 12) of positive symptoms. The task provided robust activations across the groups in areas previously associated with mentalizing abilities, such as the PFC, precuneus, and temporal lobes. Significant between-group activations were observed in the PFC (primarily BA6, 8, and 9) with the HR- activating significantly greater than the HR+ in these regions. Both a secondary state-specific analysis and a third post hoc analysis further investigating state effects showed significant PFC between-group differences. This study is the first time relatives of individuals with schizophrenia have been imaged using a ToM paradigm, and the results provide evidence of both a state and state-mediated trait effect.

A theory of mind investigation into the appreciation of visual jokes in schizophrenia.

BACKGROUND: There is evidence that groups of people with schizophrenia have deficits in Theory of Mind (ToM) capabilities. Previous studies have found these to be linked to psychotic symptoms (or psychotic symptom severity) particularly the presence of delusions and hallucinations. METHODS: A visual joke ToM paradigm was employed where subjects were asked to describe two types of cartoon images, those of a purely Physical nature and those requiring inferences of mental states for interpretation, and to grade them for humour and difficulty. Twenty individuals with a DSM-lV diagnosis of schizophrenia and 20 healthy matched controls were studied. Severity of current psychopathology was measured using the Krawiecka standardized scale of psychotic symptoms. IQ was estimated using the Ammons and Ammons quick test. RESULTS: Individuals with schizophrenia performed significantly worse than controls in both conditions, this difference being most marked in the ToM condition. No relationship was found for poor ToM performance and psychotic positive symptomatology, specifically delusions and hallucinations. CONCLUSION: There was evidence for a compromised ToM capability in the schizophrenia group on this visual joke task. In this instance this could not be linked to particular symptomatology.

Symptomatology and social inference: a theory of mind study of schizophrenia and psychotic affective disorder.

INTRODUCTION: There is evidence that certain patients with schizophrenia have deficits in theory of mind (ToM) capabilities. It is, however, unclear whether these are symptom or diagnosis-specific. METHODS: A ToM hinting task was given to 15 patients with a DSM-IV diagnosis of schizophrenia, 15 patients with affective disorder and 15 healthy controls. Severity of the current psychopathology was measured using the Krawiecka standardised scale of psychotic symptoms (Krawiecka, Goldberg, & Vaughan, 1977); IQ was estimated via the Ammons and Ammons Quick Test (Ammons & Ammons, 1962). RESULTS: The group with schizophrenia performed significantly worse than the affective and control groups. Poor performance on the hinting task was found to be significantly related to the presence of positive symptoms (instead of negative ones) and specifically related to delusions and hallucinations. These findings remained when covariance for potentially confounding variables was applied. CONCLUSIONS: Individuals with high levels of delusions and hallucinations performed significantly worse on this ToM task, regardless of diagnosis, implying ToM impairment is not exclusive to schizophrenia but is evident in other forms of psychosis. Between-group analyses showed the schizophrenia group had a significantly poorer performance on this task than the others.