Differential activity in Heschl's gyrus between deaf and hearing individuals is due to auditory deprivation rather than language modality

Sensory cortices undergo crossmodal reorganisation as a consequence of sensory deprivation. Congenital deafness in humans represents a particular case with respect to other types of sensory deprivation, because cortical reorganisation is not only a consequence of auditory deprivation, but also of language-driven mechanisms. Visual crossmodal plasticity has been found in secondary auditory cortices of deaf individuals, but it is still unclear if reorganisation also takes place in primary auditory areas, and how this relates to language modality and auditory deprivation.  Here, we dissociated the effects of language modality and auditory deprivation on crossmodal plasticity in Heschl's gyrus as a whole, and in cytoarchitectonic region Te1.0 (likely to contain the core auditory cortex). Using fMRI, we measured the BOLD response to viewing sign language in congenitally or early deaf individuals with and without sign language knowledge, and in hearing controls.  Results show that differences between hearing and deaf individuals are due to a reduction in activation caused by visual stimulation in the hearing group, which is more significant in Te1.0 than in Heschl's gyrus as a whole. Furthermore, differences between deaf and hearing groups are due to auditory deprivation, and there is no evidence that the modality of language used by deaf individuals contributes to crossmodal plasticity in Heschl's gyrus

Evidence for gesture-speech mismatch detection impairments in schizophrenia

Patients with schizophrenia suffer from impairments in the perception and production of gestures. The extent to which patients can access the semantic association between speech and co-verbal gestures in concrete or abstract/metaphorical meaning contexts is unknown. We investigated 1) how patients differ from controls in gesture matching performance, 2) how performance differs in the context of abstract versus concrete meaning, and 3) whether formal thought disorder (FTD) symptom severity predicts task impairment. Forty-five patients with schizophrenia spectrum disorders (two subgroups, mild and severe) took part in this study. Participants were presented with video clips, each showing an actor saying a sentence while producing a gesture. Sentences contained either concrete or abstract/metaphorical information, and the accompanying gesture was either semantically related or unrelated to the sentence. Participants indicated via button press whether the gesture matched the content of the verbal utterance. Both patient subgroups demonstrated reduced performance in all comparisons. A significant interaction was found between patient subgroup and sentence abstractness. Task performance was worst for patients with severe positive FTD symptomatology in the abstract condition, while there were no patient subgroup differences in the concrete condition. These data shed new light on gesture-speech mismatch detection impairments in schizophrenia.Scopu