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IntroductionCorollary discharges (CDs) are the reason most people cannot tickle themselves. They are the brain's way of distinguishing whether a stimulus is associated with one's own actions or something else. In neural terms, CDs are copies of motor plans that are propagated to sensory cortex where they can be compared with inputs. A range of phenomena associated with schizophrenia from auditory hallucinations to visual processing difficulties to the ability of patients to tickle themselves can be explained as pathologies in CD mechanisms. Auditory hallucinations for example involve patients failing to perceive themselves as the author of their own inner speech.Objectives and aimsTo test whether schizophrenia is associated with a structural network disruption that could impair CD signals involved in language processing, adolescents with schizophrenia were examined using magnetic resonance imaging and compared to healthy controls.MethodsA graph theoretical approach was used to analyse the connectivity in networks centered on:– Broca's area;– Wernicke's area.Connectivity information was acquired using diffusion tensor imaging (DTI).ResultsCompared to healthy controls, adolescents with schizophrenia displayed a lower average degree of connectivity with the left inferior frontal gyrus (Broca's area). No significant differences were found in the degree of connectivity with the right inferior frontal gyrus and the superior temporal gyrus bilaterally (Wernicke's area).ConclusionsThe results suggest a link between schizophrenia and impairment to areas where CDs associated with inner speech plausibly originate.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Background Minor motor and sensory deficits or neurological soft signs (NSS) are frequently found in patients with schizophrenia at any stage of their illness. Numerous structural magnetic resonance imaging (MRI) studies repeatedly revealed accentuated thinning of cortical mantle in schizophrenia. However, whether NSS are related to alterations of cortical thickness has so far remained mostly unexplored. Method Whole brain high-resolution MRI at 3 Tesla was used to investigate cortical thickness in twenty five patients with recent-onset schizophrenia. Cortical reconstruction was performed with the Freesurfer image analysis suite. NSS were examined on the Heidelberg Scale after remission of acute symptoms and related to cortical thickness. Age, education, medication and duration of illness were considered as potential confounders. Results Higher NSS scores were associated with decreased cortical thickness in multiple areas. Significant correlations were found in somatosensory and primary motor cortex, pre-motor area and temporal lobe. Our results confirm the hypothesis of significant relationship between alterations of cortical thickness and the extent of NSS in schizophrenia. Conclusion Our findings provide new insights into the association of NSS with brain morphometric alterations and an involvement of cortical thickness in schizophrenia.

ObjectivesMinor motor and sensory deficits or neurological soft signs (NSS) are frequently found in individuals suffering from schizophrenia at any stage of their illness. The basal ganglia and the thalamus are accepted as being important for both motor control and integration of sensory input. However, whether NSS are related to structural alterations of these brain regions remains controversial.Method20 patients with a first-episode psychosis were investigated using high-resolution magnetic resonance imaging (MRI) at 3 Tesla. NSS were examined on the Heidelberg Scale after remission of acute symptoms and correlated with volume and shape of striatum, pallidum and thalamus by using sophisticated MRI analyses, namely VBM-DARTEL (volume) and FSL-FIRST (shape).Results NSS scores in patients with schizophrenia were significantly associated with volumetric changes and surface alterations in all investigated areas. Associations remained significant when controlling for age, gender, education, medication and intracranial volume.ConclusionOur findings lend further support for an involvement of the basal ganglia and the thalamus in NSS.

BackgroundThere is increasing evidence that many of the core behavioral impairments in autism spectrum disorders (ASD) emerge from disconnectivity of networks that are important for social communication. It is less clear, which specific fiber tracts are involved and how possible alterations of white matter are associated with clinical symptomatology and neuropsychololgical characteristics in ASD.Methods18 children with ASD and 18 carefully matched typically developing controls aged 6–12 years were examined using diffusion tensor imaging (DTI) and voxel-based morphometry (VBM). Fractional anisotropy (FA) values were correlated with symptom severity as indexed by the children's scores on the Autisms Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R) and results from the Childrens Embedded Figures Test (CEFT).ResultsDecreased FA values were identified for the fornix (FO), the superior longitudinal fasciculus (SLF) the corpus callosum and the uncinate fasciculus (UF) in the ASD group compared to controls, with most prominent differences in the UF bilaterally and the right SLF. FA values of affected fiber tracts were negatively associated with clinical measures of autistic smypotmatology and response time of the CEFT. Additionally, we observed decreased grey matter concentration in the left supramarginal gyrus.ConclusionOur findings support the hypothesis of abnormal white matter microstructure of fronto-temporal cortical networks in ASD, which are associated with core symptoms of the disorder.

IntroductionNeuroimaging studies in adults with borderline personality disorder (BPD) have reported alterations in frontolimbic areas, but cannot differentiate between alterations originating from disease and those occurring as side-effects of medication or other consequences of the disorder.ObjectivesTo provide a clearer picture of the organic origins of BPD, the present study reduced such confounds by examining adolescents in the early stages of the disorder. It also examined the extent to which alterations associated with BPD are specific, or shared more broadly among other psychiatric disorders.MethodsSixty right-handed, female adolescents (14-18 years) participated. 20 had a DSM-IV diagnosis of BPD, 20 had a different DSM-IV defined psychiatric disorder, and 20 were healthy controls. All groups were matched for age and IQ. Images were analysed using voxel-based morphometry.ResultsNo differences were found in limbic or white matter structures. Compared to healthy controls, adolescents with BPD displayed reduced gray matter in dorsolateral prefrontal cortex bilaterally and in left orbitofrontal cortex, but there were no significant differences in gray matter between BPD and other psychiatric patients. Like BPD patients, non-BPD psychiatric patients displayed significantly less gray matter in right dorsolateral prefrontal cortex compared to healthy controls.ConclusionsThese findings indicate that the prefrontal cortex is the earliest affected in the progression of BPD, but this does not distinguish it clearly from other psychiatric disorders. Alterations in limbic areas and white matter structures were not observed, but may play a later role in the progression of the illness.