The role of interpersonal synchrony in forming impressions of autistic and non-autistic adults

When people meet, they almost instantaneously form an impression of each other. First impressions of character traits and rapport are less favourable when people with autism spectrum condition (ASC) are judged compared to non-autistic people. Little is known about the behavioural differences that drive these altered impressions. In the present study, we investigated the influence of interpersonal synchrony on impression formation of autistic and non-autistic people. Specifically, we used lagged cross-correlations to assess how much each interactant's motion energy, a measure which can be determined from video recordings, influenced the other interactant's motion energy. In short, silent clips of dyadic conversations, we asked non-autistic participants to rate their impression of one of the two interactants, which was solely based on the outlines of both interactants. We expected that the amount of leading of the target interactant, their diagnostic status as well as the interaction of these factors would influence impression formation. We found that while the amount of leading had a positive effect on the impressions of non-autistic interactants, this was not true for interactants with ASC. This suggests that interpersonal synchrony of motion energy is one driver of less favourable impressions of autistic compared to non-autistic people.

Language and turn-taking in schizophrenia spectrum disorders

Introduction

Language and conversation are deeply interrelated: language is acquired, structured, practiced in social interactions and linguistic resources (specifically syntactic, prosodic and pragmatic aspects) contribute to finely tuning turn-taking. Nevertheless, most studies focused on verbal aspects of speech in schizophrenia, with scant attention to their relation to conversation, where language is experienced at most.

Objectives

The present study was aimed at investigating a possible association between language impairment and conversational characteristics in a sample of clinically stable patients diagnosed with schizophrenia (N = 35, ages 18-65).

Methods

A spontaneous speech sample was recorded. For the assessment of language skills, the Scale for the Assessment of Thought, Language and Communication (TLC) and the Clinical Language Disorder Rating Scale (CLANG) were used, while conversational variables were extracted with an innovative method of semi-automatic analysis. The possible associations were investigated through the Pearson Correlation.

Results

Figure 1 represents graphically the correlational matrix between conversational variables and linguistic scale scores. In the heatmap, blue means negative and red positive correlations, the stronger the colour, the larger the correlation magnitude. Moreover, the significant associations are indicated with stars.

Conclusions

The results suggest that in schizophrenia spectrum disorders the disturbances of language, at a syntactic, prosodic and pragmatic level, have significant impact on communicative interaction.

Thus, conversation analysis might be a promising method to quantify objectively communicative impairment with the benefit of representing an ecological assessment, examining the performance of patients in the real situation of language use, which is social interaction.

Disclosure

No significant relationships.

Brief Report: Preferred Processing of Social Stimuli in Autism: A Perception Task

In this study we investigate whether persons with autism spectrum disorder (ASD) perceive social images differently than control participants (CON) in a graded perception task in which stimuli emerged from noise before dissipating into noise again. We presented either social stimuli (humans) or non-social stimuli (objects or animals). ASD were slower to recognize images during their emergence, but as fast as CON when indicating the dissipation of the image irrespective of its content. Social stimuli were recognized faster and remained discernable longer in both diagnostic groups. Thus, ASD participants show a largely intact preference for the processing of social images. An exploratory analysis of response subsets reveals subtle differences between groups that could be investigated in future studies.

Brief Report: Social Anxiety in Autism Spectrum Disorder is Based on Deficits in Social Competence

This study differentially examined the relation between two clinical constructs: “social anxiety” and “social competence” in autism spectrum disorder (ASD). Employing two questionnaires (SASKO; IU), individuals with ASD (n = 23) showed increased scores of SOCIAL ANXIETY (SASKO) and of INTOLERANCE OF UNCERTAINTY (IU), compared to a non-clinical comparison group (NC; n = 25). SOCIAL ANXIETY scores were equally increased for ASD and a reference population of individuals with social anxiety disorder (SAD; n = 68). However, results showed increased SOCIAL COMPETENCE DEFICITS in ASD compared to SAD and NC groups. This study allows drawing the conclusion that social anxiety symptoms in ASD can be traced back to autism-specific deficits in social skills and are therefore putatively based on different, substantially “deeper” implemented cognitive mechanisms.

Reduced nonverbal interpersonal synchrony in autism spectrum disorder independent of partner diagnosis: a motion energy study

BACKGROUND

One of the main diagnostic features of individuals with autism spectrum disorders is nonverbal behaviour difficulties during naturalistic social interactions. The 'Interactional Heterogeneity Hypothesis' of ASD proposes that the degree to which individuals share a common ground substantially influences their ability to achieve smooth social interactions.

METHODS

To test this hypothesis, we filmed 29 autistic and 29 matched typically developed adults engaged in several conversational tasks. Windowed cross-lagged correlations were computed using the time series of motion energy of both individuals in a dyad. These coefficients were then compared across the three dyad types that were homo- or heterogenous with respect to diagnosis: pairs of two autistic individuals, two typically developed individuals or pairs of one autistic and one typically developed person.

RESULTS

We found that all dyad types achieved above-chance interpersonal synchrony, but that synchrony was more expressed in typical dyads compared to both autistic and mixed dyads.

LIMITATIONS

The method presented here provides only one, albeit objective and robust, approach to explore synchrony. The methodological choices as well as the lack of consideration for other communication modalities may limit our interpretation of the findings. Moreover, the sample size is small with respect to exploring associations between synchrony and various outcome and social skill measures.

CONCLUSIONS

The present results do not provide support for the Interactional Heterogeneity Hypothesis given that autistic individuals do not coordinate better when interacting with another autistic individual, compared to when interacting with a typical individual.

Disturbed time experience during and after psychosis

Disturbances in time experience have been argued to play a significant, if not causative role in the clinical presentation of schizophrenia. Phenomenological considerations suggest a fragmented or dis-articulated time experience causing both primary symptoms such as hallucinations, delusions, and self-disorders, as well as an intersubjective desynchronization. We employed content analysis on material collected from patients diagnosed with schizophrenia using the Time Questionnaire to generate hypotheses on possible disturbances of time experience in schizophrenia. As a key result we find evidence for the distinction between acute psychotic and post-psychotic syndromes. Acute psychosis is predominantly a disturbance of the passage of time, whereas the remission from psychosis is primarily defined by changes in the experience of the explicit structure of time integrating past, present, and future. We discuss our findings with regards to previous insights and observations on time experience and time perception. We suggest our findings hold significance for the diagnostic and therapeutic understanding of schizophrenia as well as for future integrative research on time experience in general.

Young adolescents with autism show abnormal joint attention network: A gaze contingent fMRI study

Behavioral research has revealed deficits in the development of joint attention (JA) as one of the earliest signs of autism. While the neural basis of JA has been studied predominantly in adults, we recently demonstrated a protracted development of the brain networks supporting JA in typically developing children and adolescents. The present eye-tracking/fMRI study now extends these findings to adolescents with autism. Our results show that in adolescents with autism JA is subserved by abnormal activation patterns in brain areas related to social cognition abnormalities which are at the core of ASD including the STS and TPJ, despite behavioral maturation with no behavioral differences. Furthermore, in the autism group we observed increased neural activity in a network of social and emotional processing areas during interactions with their mother. Moreover, data indicated that less severely affected individuals with autism showed higher frontal activation associated with self-initiated interactions. Taken together, this study provides first-time data of JA in children/adolescents with autism incorporating the interactive character of JA, its reciprocity and motivational aspects. The observed functional differences in adolescents ASD suggest that persistent developmental differences in the neural processes underlying JA contribute to social interaction difficulties in ASD.

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Gaze-contingent fMRI task to study joint attention in a developmental sample with autism

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JA in the autism group elicited abnormal activation in social cognition related areas.

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The interaction partner's familiarity modulated brain activity in the autism group.

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In the autism group frontal activation is related to the severity of communication deficits.

Interpersonal predictive coding, not action perception, is impaired in autism

This study was conducted to examine interpersonal predictive coding in individuals with high-functioning autism (HFA). Healthy and HFA participants observed point-light displays of two agents (A and B) performing separate actions. In the ‘communicative’ condition, the action performed by agent B responded to a communicative gesture performed by agent A. In the ‘individual’ condition, agent A's communicative action was substituted by a non-communicative action. Using a simultaneous masking-detection task, we demonstrate that observing agent A's communicative gesture enhanced visual discrimination of agent B for healthy controls, but not for participants with HFA. These results were not explained by differences in attentional factors as measured via eye-tracking, or by differences in the recognition of the point-light actions employed. Our findings, therefore, suggest that individuals with HFA are impaired in the use of social information to predict others' actions and provide behavioural evidence that such deficits could be closely related to impairments of predictive coding.

[Diagnosis and Therapeutic Interventions in Autism Spectrum Disorders in Adulthood]

Autism spectrum disorders (ASD) are characterized by disturbed social interaction and communication as well as stereotyped or repetitive behaviors and interests. Although adults with ASD often acquire complex compensatory strategies that help them master social situations in a rule-based fashion, they still show impairments in intuitive processing of social signals and especially nonverbal communication in complex everyday situations. This constitutes a particular challenge for the psychotherapy of ASD. Psychotherapists are required to explicitly inform and act as an agent of the non-autistic world to enable patients to acquire the ability to take different perspectives. The overall aim of cognitive behavioral therapy interventions addressing ASD in adulthood is to extend the patients' behavioral repertoire to improve their quality of life. Thus, besides psychoeducation on ASD and its frequently associated comorbidities, psychotherapy for adults with ASD should focus on the training and development of social-communicative skills. Furthermore, dealing with stress in everyday situations is an important aspect of psychotherapy of these patients.

Look into my eyes: Investigating joint attention using interactive eye-tracking and fMRI in a developmental sample

Joint attention, the shared attentional focus of at least two people on a third significant object, is one of the earliest steps in social development and an essential aspect of reciprocal interaction. However, the neural basis of joint attention (JA) in the course of development is completely unknown. The present study made use of an interactive eye-tracking paradigm in order to examine the developmental trajectories of JA and the influence of a familiar interaction partner during the social encounter. Our results show that across children and adolescents JA elicits a similar network of "social brain" areas as well as attention and motor control associated areas as in adults. While other-initiated JA particularly recruited visual, attention and social processing areas, self-initiated JA specifically activated areas related to social cognition, decision-making, emotions and motivational/reward processes highlighting the rewarding character of self-initiated JA. Activation was further enhanced during self-initiated JA with a familiar interaction partner. With respect to developmental effects, activation of the precuneus declined from childhood to adolescence and additionally shifted from a general involvement in JA towards a more specific involvement for self-initiated JA. Similarly, the temporoparietal junction (TPJ) was broadly involved in JA in children and more specialized for self-initiated JA in adolescents. Taken together, this study provides first-time data on the developmental trajectories of JA and the effect of a familiar interaction partner incorporating the interactive character of JA, its reciprocity and motivational aspects.

Attenuated prefrontal activation during decision-making under uncertainty in schizophrenia: a multi-center fMRI study

Decisions are called decisions under uncertainty when either prior information is incomplete or the outcomes of the decision are unclear. Alterations in these processes related to decisions under uncertainty have been linked to delusions. In patients with schizophrenia, the underlying neural networks have only rarely been studied. We aimed to disentangle the neural correlates of decision-making and relate them to neuropsychological and psychopathological parameters in a large sample of patients with schizophrenia and healthy subjects. Fifty-seven patients and fifty-seven healthy volunteers from six centers had to either indicate via button-press from which of two bottles red or blue balls were drawn (decision-making under uncertainty condition), or indicate whether eight red balls had been presented (baseline condition) while BOLD signal was measured with fMRI. Patients based their decisions on less conclusive evidence and had decreased activations in the underlying neural network, comprising of medial and lateral frontal as well as parietal areas, as compared to healthy subjects. While current psychopathology was not correlated with brain activation, positive symptoms led to longer decision latencies in patients. These results suggest that decision-making under uncertainty in schizophrenia is affected by a complex interplay of aberrant neural activation. Furthermore, reduced neuropsychological functioning in patients was related to impaired decision-making and task performance was modulated by distinct positive symptoms.

Toward the development of a supported employment program for individuals with high-functioning autism in Germany

Human-human interactions are of central relevance for the success in professional and occupational environments, which also substantially influence quality of life. This is especially true in the case of individuals with high-functioning autism (HFA), who experience deficits in social cognition that often lead to social exclusion and unemployment. Despite good education and high motivation, individuals with HFA do not reach employment rates that are substantially higher than 50 %. This is an alarmingly high rate of unemployment considering that the United Nations have recently emphasized the inclusion of handicapped persons as a mandatory human right. To date, the specific needs of autistic persons with respect to their working environment are largely unexplored. It remains moreover an open question how support systems and activities, including newly developed communication devices for professional environments of individuals with HFA, should look like. The German health and social care systems are not adequately prepared for the proper support of this population. This leads us to suggest that supported employment programs should be developed for adults with HFA that specifically address their needs and requirements. Such programs should comprise (1) the adequate assessment of HFA, including a neuropsychological profile and an individual matching of persons' preferences with requirements of the working place, (2) on-the-job coaching activities that include systematic communication and interaction training, and (3) instruction of non-autistic peers, including colleagues and supervisors, about weaknesses and strengths of HFA.

To you I am listening: perceived competence of advisors influences judgment and decision-making via recruitment of the amygdala

Considering advice from others is a pervasive element of human social life. We used the judge-advisor paradigm to investigate the neural correlates of advice evaluation and advice integration by means of functional magnetic resonance imaging. Our results demonstrate that evaluating advice recruits the "mentalizing network," brain regions activated when people think about others' mental states. Important activation differences exist, however, depending upon the perceived competence of the advisor. Consistently, additional analyses demonstrate that integrating others' advice, i.e., how much participants actually adjust their initial estimate, correlates with neural activity in the centromedial amygdala in the case of a competent and with activity in visual cortex in the case of an incompetent advisor. Taken together, our findings, therefore, demonstrate that advice evaluation and integration rely on dissociable neural mechanisms and that significant differences exist depending upon the advisor's reputation, which suggests different modes of processing advice depending upon the perceived competence of the advisor.

[Psychosocial functioning of adults with late diagnosed autism spectrum disorders--a retrospective study]

BACKGROUND

The first time diagnosis of autism spectrum disorder (ASD) after passing childhood and adolescence is still considered a rare event. However, in recent years an increasing demand for diagnostic clarifications with suspected ASD in adulthood challenges this view. There is insufficient knowledge about the neuropsychological characterisation and psychosocial outcome of this adult subgroup in the autistic spectrum.

AIM

To determine the psychosocial functioning (living status, partnerships, level of education, psychiatric history) of adult patients with late diagnosed ASD.

METHODS

In a retrospective study, a chart review was conducted on 178 consecutively diagnosed individuals at a specialised outpatient clinic for adults with ASD. Global ratings of psychosocial functioning, assessment of psychiatric history and neuropsychological and psychopathological investigations were evaluated.

RESULTS

The majority of patients (92 %) diagnosed with ASD suffered from high-functioning autism (HFA)/Asperger syndrome (AS) according to the criteria of ICD-10 (F84.5). The gender ratio was 2:1 favouring males. Mean age at diagnosis (34.1 ± 9.5 years), general intelligence (HAWIE-R, global-IQ 115 ± 20) and self-rated autistic symptoms (autism spectrum quotient [AQ] 39 ± 6) were not discriminative to gender. The psychiatric history revealed a lifetime consultation rate of 78 %, most frequently with depression (50 %). The self-report instrument Beck depression inventory (BDI) identified 30 % of individuals presenting with depressive symptoms in clinical relevant intensity (BDI > 17). Achievement of an independent living status was reported by 68 % of individuals, 58 % reported about current or past intimate partnerships and almost two-thirds of the patients had achieved a higher educational status.

DISCUSSION

The majority of ASD diagnosed late in lifetime turned out to be HFA/AS, presenting with high psychosocial adjustment with regard to independent living, educational status and partnerships. The high level of global intelligence supports the hypothesis of cognitively compensated autistic disturbances leading to the diagnosis comparably late in lifetime. The lifetime rate of psychiatric consultations is high, reflecting the importance to consider a diagnosis of ASD even late in life.

Animated brain: a functional neuroimaging study on animacy experience

Previous research used animated geometric figures to investigate social cognitive processes involved in ascribing mental states to others (e.g. mentalizing). The relationship between animacy perception and brain areas commonly involved in social cognition, as well as the influence of particular motion patterns on animacy experience, however, remains to be further elucidated. We used a recently introduced paradigm for the systematic variation of motion properties, and employed functional magnetic resonance imaging to identify the neural mechanisms underlying animacy experience. Based on individual ratings of increased animacy experience the following brain regions of the "social neural network" (SNN), known to be involved in social cognitive processes, were recruited: insula, superior temporal gyrus, fusiform gyrus, parahippocampal gyrus and the ventromedial prefrontal cortex bilaterally. Decreased animacy experience was associated with increased neural activity in the inferior parietal and inferior frontal gyrus, key constituents of the human "mirror neuron system" (hMNS). These findings were corroborated when analyses were based on movement patterns alone, irrespective of subjective experience. Additionally to the areas found for increased animacy experience, an increase in interactive movements elicited activity in the amygdala and the temporal pole. In conclusion, the results suggest that the hMNS is recruited during a low-level stage of animacy judgment representing a basic disposition to detect the salience of movements, whereas the SNN appears to be a high-level processing component serving evaluation in social and mental inference.

Neural correlates of first-person perspective as one constituent of human self-consciousness

Taking the first-person perspective (1PP) centered upon one's own body as opposed to the third-person perspective (3PP), which enables us to take the viewpoint of someone else, is constitutive for human self-consciousness. At the underlying representational or cognitive level, these operations are processed in an egocentric reference frame, where locations are represented centered around another person's (3PP) or one's own perspective (1PP). To study 3PP and 1PP, both operating in egocentric frames, a virtual scene with an avatar and red balls in a room was presented from different camera viewpoints to normal volunteers (n = 11) in a functional magnetic resonance imaging experiment. The task for the subjects was to count the objects as seen either from the avatar's perspective (3PP) or one's own perspective (1PP). The scene was presented either from a ground view (GV ) or an aerial view (AV ) to investigate the effect of view on perspective taking. The factors perspective (3PP vs. 1PP) and view (GV vs. AV ) were arranged in a two-factorial way. Reaction times were increased and percent correctness scores were decreased in 3PP as opposed to 1PP. To detect the neural mechanisms associated with perspective taking, functional magnetic resonance imaging was employed. Data were analyzed using SPM'99 in each subject and non-parametric statistics on the group level. Activations common to 3PP and 1PP (relative to baseline) were observed in a network of occipital, parietal, and prefrontal areas. Deactivations common to 3PP and 1PP (relative to baseline) were observed predominantly in mesial (i.e., parasagittal) cortical and lateral superior temporal areas bilaterally. Differential increases of neural activity were found in mesial superior parietal and right premotor cortex during 3PP (relative to 1PP), whereas differential increases during 1PP (relative to 3PP) were found in mesial prefrontal cortex, posterior cingulate cortex, and superior temporal cortex bilaterally. The data suggest that in addition to joint neural mechanisms, for example, due to visuospatial processing and decision making, 3PP and 1PP rely on differential neural processes. Mesial cortical areas are involved in decisional processes when the spatial task is solved from one's own viewpoint, whereas egocentric operations from another person's perspective differentially draw upon cortical areas known to be involved in spatial cognition.

[The importance of interneurons in schizophrenic and affective disorders]

In brains of patients with schizophrenic and affective disorders pathomorphological changes have been shown focussing in frontal and temporal cortex. The volume reduction in prefrontal cortex of schizophrenic patients is hypothesized to be based on a reduction of neuropil. A decrease of synaptic proteins and a decrease of dendritic spines of pyramidal cells can additionally be the origin of disconnections of neurons. Affection of the glutamatergic, GABA-ergic and dopaminergic system and reduction of interneurons could be the correlate of a deficient neuronal network which might be combined with exogen factors generate psychotic symptoms. Reelin and associated proteins are candidate molecules. Their dysregulation might explain essential features of the dysfunctional network of schizophrenia.

Mind reading: neural mechanisms of theory of mind and self-perspective

Human self-consciousness as the metarepresentation of ones own mental states and the so-called theory of mind (TOM) capacity, which requires the ability to model the mental states of others, are closely related higher cognitive functions. We address here the issue of whether taking the self-perspective (SELF) or modeling the mind of someone else (TOM) employ the same or differential neural mechanisms. A TOM paradigm was used and extended to include stimulus material that involved TOM and SELF capacities in a two-way factorial design. A behavioral study in 42 healthy volunteers showed that TOM and SELF induced differential states of mind: subjects assigned correctly first or third person pronouns when providing responses to the stimuli. Following the behavioral study, we used functional magnetic resonance imaging (fMRI) in eight healthy, right-handed males to study the common and differential neural mechanisms underlying TOM and SELF. The main factor TOM led to increased neural activity in the anterior cingulate cortex and left temporopolar cortex. The main factor SELF led to increased neural activity in the right temporoparietal junction and in the anterior cingulate cortex. A significant interaction of both factors TOM and SELF was observed in the right prefrontal cortex. These divergent neural activations in response to TOM and SELF suggest that these important differential mental capacities of human self-consciousness are implemented at least in part in distinct brain regions. Press

[Structural brain changes in patients with schizophrenic psychoses. From focal pathology to network disorder]

Schizophrenia is a brain disorder characterized by a heterogeneous clinical symptomatology. Accordingly, many structural brain changes are not associated directly with clinical symptoms. These structural changes can be detected in the frontotemporal cortex and may correlate with the course of the disease. The most important etiological concept is the neurodevelopmental hypothesis according to which developmental, morphologically detectable changes predispose for the acquisition of schizophrenia. The relevance of neurodegenerative components also remains to be determined. However, it is becoming increasingly clear that schizophrenia is not associated with pathological changes in a circumscribed brain region but with widely distributed morphological changes. Presently, the leading hypothesis for explaining these changes is a frontotemporolimbic network disturbance with cytoarchitectural changes in the heteromodal association cortex. Present research therefore focuses on testing this theory using functional imaging on a macroscopic level and examination of the neuronal cytoarchitecture on a microscopic level.

Right frontal hypergyria differentiation in affected and unaffected siblings from families multiply affected with schizophrenia: a morphometric mri study

OBJECTIVE

The authors used magnetic resonance imaging to corroborate the postmortem finding of right frontal hypergyria associated with schizophrenia.

METHOD

Twelve affected-unaffected sibling pairs from families multiply affected with schizophrenia were studied. Bilateral measurement of the gyrification index, the ratio of the inner and outer surface contours, was performed on three different slices of the prefrontal region.

RESULTS

The mean gyrification index on the right side was significantly higher in siblings with schizophrenia or schizoaffective disorder than in the unaffected siblings.

CONCLUSIONS

In this family cohort study, the postmortem finding of right-sided hypergyria in subjects with schizophrenia was replicated in vivo with magnetic resonance imaging. This observation provides further support for a neurodevelopmental mechanism in the pathogenesis of schizophrenia.

Automated image analysis of disturbed cytoarchitecture in Brodmann area 10 in schizophrenia: a post-mortem study

1. Among different etiological concepts in schizophrenia research is the disconnect on hypothesis involving distributed brain regions. Adequate empirical research requires correlational studies of multiple brain regions. In this pilot study, the authors therefore tested the applicability of an automated image analysis device as a scanning tool to detect cytoarchitectural abnormalities in Brodmann area (BA) 10. 2. The authors applied the gray level index (GLI) method as automated image analysis on 10 schizophrenic brains compared to 10 controls. The GLI as perikarya-neuropil-ratio is obtained as the ratio between the area covered by cellular cross sections and the area of the total measuring field in 101 continous measuring fields from pial surface to the cortical depth. Resulting data provide a specific cytoarchitectonic profile curve. An analysis was performed separately for mean GLI and GLI values in six compartments covering approximately the different cortical laminae. 3. A statistically significant reduction of the mean GLI was demonstrated in the schizophrenic group covering laminae III to VI, as detected by multivariate analysis and corroborated by univariate analyses and t-tests. 4. This result clearly underlines a cytoarchitectonic disturbance with a perikarya neuropil-ratio reduction in BA 10, that is associated with schizophrenia. This is suggestive either of an increased neuropil fraction or a decreased neuronal perikarya fraction. The latter could either be due to a volume or a total number reduction of neuronal perikarya. These data are compatible with previously published data on cell loss in schizophrenics in BA 10.

[The chances of new atypical substances]

Antipsychotic treatment with so-called "atypical" neuroleptics, as defined by the lack of extrapyramidal side effects in its strict sense, has made great advances in the last decades with the advent of newly developed antipsychotic agents. The first atypical neuroleptic drug was clozapine, also referred to as "dirty drug" or "rich drug" because of its broad receptor binding profile. Clozapine has been the starting point for several different, newly developed antipsychotics. Among these, the most prominent are olanzapine, risperidone, sertindol, ziprasidone, and amisulpride. All of these newly developed, atypical antipsychotics show a high degree of efficacy in the treatment of positive symptoms of schizophrenia in combination with a lack of or a reduced degree of extrapyramidal side effects (EPS). In addition, several atypical antipsychotics seem to have an additional impact on negative symptoms such as alogia, anhedonia, or avolition. However, apart from the clear advantage of clozapine in the treatment of otherwise treatment-resistant schizophrenia, differential indications for the different antipsychotics remain to be established.

Disturbed gyrification of the prefrontal region in male schizophrenic patients: A morphometric postmortem study

OBJECTIVE

The goal was to test the hypothesis that abnormalities of gyrification are present in the prefrontal region of postmortem brains from schizophrenic patients.

METHOD

The authors compared the prefrontal regions in brains from 24 schizophrenic patients and 24 normal comparison subjects. The gyrification index, the ratio of inner and outer surface contours, was measured bilaterally in three different slices from each brain. Area measurements of gray and white matter were studied separately by planimetric analysis in the same sections. In addition, a gray-to-white-matter ratio and an asymmetry coefficient were computed.

RESULTS

The mean gyrification index on the right side was significantly higher in the male schizophrenic patients than in the comparison men. The gyrification index of the female patients was not significantly different from that of the female comparison subjects. Analysis of area measurements revealed no significant differences.

CONCLUSIONS

As gyrification is an ontogenetic stable feature unaffected by atrophic processes during aging, the gyrification abnormalities of the prefrontal region provide further evidence of the importance of a neurodevelopmental mechanism in the etiology of schizophrenia, at least in males.

Essential functions of the human self model are implemented in the prefrontal cortex

The human self model comprises essential features such as the experiences of ownership, of body-centered spatial perspectivity, and of a long-term unity of beliefs and attitudes. In the pathophysiology of schizophrenia, it is suggested that clinical subsyndromes like cognitive disorganization and derealization syndromes reflect disorders of this self model. These features are neurobiologically instantiated as an episodically active complex neural activation pattern and can be mapped to the brain, given adequate operationalizations of self model features. In its unique capability of integrating external and internal data, the prefrontal cortex (PFC) appears to be an essential component of the neuronal implementation of the self model. With close connections to other unimodal association cortices and to the limbic system, the PFC provides an internally represented world model and internal milieu data of the organism, both serving world orientation. In the pathophysiology of schizophrenia, it is the dysfunction of the PFC that is suggested to be the neural correlate for the different clinical schizophrenic subsyndromes. The pathophysiological study of psychiatric disorders may contribute to the theoretical debate on the neuronal basis of the self model.

Pictorial pseudohallucinations with an "aperture effect" in a patient with quadrantanopia

Visual pseudohallucinations are reported on in a patient with a left lower quadrantanopia due to a right parietotemporal surgical defect after tumour removal. Besides metamorphopsia, he hallucinated the lower half of human figures which were limited to within the borders of the anopic defect and appeared "amputated" at the hip with one forearm and hand appearing from above in correct anatomical position. The lower half of these human figures was perceived as correctly scaled in relation to anatomical and environmental coordinates and was recognised as unreal. These pseudohallucinations led to the concept of an "aperture effect" which alludes to the visibility through the anopic field defect of a segment of the contents of the visual association cortex. This supports the idea of a pictorial mode for representation of endogenously generated images in the visual association cortex.

Compartmental volumetry of the superior temporal gyrus reveals sex differences in schizophrenia--a post-mortem study

Brain imaging studies have shown superior temporal gyrus (STG) volume loss and abnormal patterns of asymmetry in schizophrenia; however, these are not consistent findings. Post-mortem volumetry of three different STG regions (defined by external landmarks) was used to compare 17 schizophrenics to 20 age- and sex-matched controls. Total STG volumes did not differ. A significant gray-matter volume reduction in schizophrenics was observed in the middle compartment (reaching from the mamillary body to the lateral geniculate body). This may have been related to reduced length of this region, particularly in schizophrenic females. These results reflect the problematic issue of defining boundaries of macroscopic brain structures.

The stromal Schwann cell during maturation of peripheral neuroblastomas. Immunohistochemical observations with antibodies to the neuronal class III beta-tubulin isotype (beta III) and S-100 protein

This immunohistochemical study compares the localization of the neuronal class III beta-tubulin isotype (beta III; analogous to the beta' 1-/beta 2-tubulin isoform) to the Schwann cell-associated S-100 protein focusing on topographic relationships of Schwann-like cells to differentiating neuronal phenotypes during stromal development in human peripheral neuroblastomas. The earliest appearance of Schwann cells in poorly differentiated (classical) neuroblastomas is heralded by S-100 protein-immunoreactive cells in close association with tumor blood vessels. In subsequent stages of maturation, i.e. maturing neuroblastoma (ganglioneuroblastoma and gangliocytoma), S-100 protein-positive cells are mostly confined to the connective tissue septa dividing tumor into lobules, and are not freely interspersed with beta III-immunoreactive neoplastic neurons. Significant ensheathment of individual axon-like processes by Schwann cells occurs only in mature ganglioneuromas. beta III is localized in a full spectrum of neoplastic neuronal phenotypes, ranging from poorly-differentiated apolar neuroblasts (often signaling ensuing neuritogenesis) to mature ganglion cells, but not in Schwann cells, or other cell types of the stroma. Our observations suggest that Schwann cells in peripheral neuroblastomas are stroma-derived cells and not an expression of divergent neoplastic differentiation.