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Background In mental illnesses, the language domain, including speech and thought, is often affected. The spectrum of language symptoms shows a great variability between patients with psychosis. In previous studies, we have not only demonstrated that patients and healthy controls show activation differences in the neural language circuitry, but also within the different patient groups. The Bern psychopathology scale is a tool to help differentiate patients, which presents with disinhibited or inhibited language symptoms. This aids to examine the continuum from health to psychosis in a dimensional approach. To understand the bipolarity within the patient groups on the continuum of language domain, the healthy population needs to be examined as well. Therefore, in the current study, a healthy population was tested to investigate this heterogeneity in the language domain during a lexical decision task. Additionally, a subjective rating of one’s language aptitude was measured, to gain an insight on where they would see themselves on the continuum. The aim was to examine the spectrum of inter-individual differences and its association with language-related brain networks, specifically Broca’s and Wernicke’s area. This observed heterogeneity of a healthy population would allow an extrapolation to clinical ends of the spectrum. Methods While measuring brain activity with fMRI, 102 healthy adult subjects performed a lexical priming task. Subjects had to decide if a visually presented target word would form the generic term of a previously shown prime word, in terms of its relation (e.g. Dog – Cat) or its category (e.g. Dog – Animal). To group the participants, each subject rated their own language aptitude on 7-point Likert scale. According to their rating they were then sorted into high, mid or low language aptitude groups. Results Although, we found differences in brain activation in Broca (BA44/ BA45) and Wernicke (pMTG) among the groups, the behavioral outcome, specifically reaction time (RT) and accuracy, showed no significant differences between the groups. We studied the activation patterns in the region of Broca’s area (BA45, BA44) and Wernicke’s area (pMTG) during preparation (waiting for the target after the indication of task type) and processing (target word processing) phases. We found group differences in BA45 during both preparation and processing phases. The Post hoc analysis revealed that the high group showed significantly greater activation in BA45 compared to the low group. While BA44 and pMTG showed only a significant group difference during the processing phase. Also, here the Post hoc analysis revealed that the high group showed greater activation in both areas during the processing phase. Furthermore, the psychophysiological interaction (PPI) analysis of BA44, during preparation phase, with RT as covariate revealed distinct functional connectivity patterns from seed area BA44 among the high and low language aptitude groups. We found, that a stronger connectivity from BA44 to the left posterior middle temporal gyrus (pMTG) was related with faster RT in the high group. The low group showed a same pattern from BA44 to the left fusiform gyrus, also known as the visual word form area. Discussion These results indicate that, one utilizes the language-related brain areas differently, as well as their connectivity, during the language task according to the subjective evaluation of oneself language aptitude. These new insights into the dimension of language is facilitating further research in psychosis, that analyzes the continuum from the healthy population profiles to the profiles of the population with psychosis. With this, it supports the efforts to improve diagnostic tools and treatment options for patients with psychosis.

Schizophrenia is characterized by social interaction deficits contributing to poor functional outcome. Hand gesture use is particularly impaired, linked to frontal lobe dysfunction and frontal grey matter deficits. The functional neural correlates of impaired gesturing are currently unclear. We therefore investigated aberrant brain activity during impaired gesturing in schizophrenia. We included 22 patients with schizophrenia and 25 healthy control participants matched for age, gender, and education level. We obtained functional magnetic resonance imaging data using an event-related paradigm to assess brain activation during gesture planning and execution. Group differences in whole brain effects were calculated using factorial designs. Gesture ratings were performed by a single rater, blind to diagnoses and clinical presentation. During gesture planning and execution both groups activated brain areas of the praxis network. However, patients had reduced dorsolateral prefrontal cortex (DLPFC) and increased inferior parietal lobe (IPL) activity. Performance accuracy was associated with IPL activity in patients. Furthermore, patients activated temporal poles, amygdala and hippocampus during gesture planning, which was associated with delusion severity. Finally, patients demonstrated increased dorsomedial prefrontal cortex activity during planning of novel gestures. We demonstrate less prefrontal, but more IPL and limbic activity during gesturing in schizophrenia. IPL activity was associated with performance accuracy, whereas limbic activity was linked to delusion severity. These findings may reflect impaired social action planning and a limbic interference with gestures in schizophrenia contributing to poor gesture performance and consequently poor social functioning in schizophrenia.

Background: Formal thought disorders (FTD) are a core symptom in schizophrenia. One key challenge remains the heterogeneity of FTD. Here we focus on state cerebral blood flow (rCBF) linked to severity of subtypes of FTD. We hypothesized distinguishable alterations in the language network linked to subtypes of FTD in schizophrenia associated with functioning after 6 month.

Background Hand gestures are an integral part of social interactions and are involved in nonverbal and verbal communication. The convey language that is expressed by motor actions, and thus depend on the interplay of various brain regions. Several functional magnetic resonance imaging studies in healthy subjects suggest the praxis network for gesture production, involving distinct frontal, parietal and temporal regions. Lesions studies in subjects with apraxia, following left brain damage corroborate these findings. However, little is known about the structural connectivity underlying gesture production. We aimed to provide novel insights into the structural connectivity of the praxis network and how it is related to gesture production. Methods Our sample consisted of 41 healthy subjects and of 40 patients with schizophrenia, demonstrating gesture impairments and structural network abnormalities. All participants performed a gesture production test, the test of upper limb apraxia and underwent diffusion weighted magnetic resonance imaging. Finsler geometry was used to investigate structural connectivity and graph theory to estimate global and local efficiency of the praxis network, which consists of 13 bilateral regions of interest. Results Our findings showed an association of gesture production with network attributes and specific connections within the praxis network. Thus, global and local efficiency and most of the intra- and interhemispheric connections within the gesture network predicted gesture production across groups. Global efficiency of the praxis network further predicted gesture production only in the patient group. Local efficiency of many ROIs and connections of interest predicted production in patients at trend-level. In contrast, there were no significant or trend-level associations of gesture production with network attributes in controls. Discussion The results revealed an association of impaired gesture performance with structural alterations of the praxis network, including global and local efficiency and many connections of interest. Our findings are of great importance in the understanding of the structural correlates of gesture production and shed further light on the neural underpinnings of gesture deficits in a patient group with severe social deficits.