Strong connections of locally clustered neurons in the upper-layer cortex underlie schizophrenia-related auditory deviance detection.

The detection of unexpected sounds, or auditory deviance detection, is thought to be achieved by comparing prediction signals and sensory inputs in the auditory cortex. This process is markedly impaired in patients with schizophrenia. However, the local circuit properties underlying deviance detection, together with their dysfunction in schizophrenia-related conditions, remain poorly understood. We used two-photon calcium imaging to monitor the population activity of cortical neurons during auditory deviance detection. The deviance-detecting component was predominant in layer 2/3 neurons of the higher-order auditory cortex. The deviance-detecting cells were spatially clustered, exhibited robust synchronization, and constitutively expressed immediate-early genes. In the Del(1.5 megabase)/+ mouse model of 22q11.2 deletion syndrome, a model of schizophrenia, deviance-detecting activity in the upper-layer network was disrupted, accompanied by dysregulated gene expression and selective loss of dendritic spines in immediate-early gene-positive neurons. Our findings support the hypothesis that ensemble activation of this neuronal subpopulation amplifies unexpected inputs, driving error signals that propagate to higher-order cortical areas.