Paroxetine can improve primary visual cortex activity in a high-risk mouse model of schizophrenia

Visual cortex functional deficits can be observed in schizophrenia patients and in individuals at high risk of schizophrenia. However, to date, few studies have investigated methods to improve these functional deficits. This study aimed to investigate the pathological change in the primary visual cortex of a prenatal MK-801-induced high-risk mouse model of schizophrenia (HRMMS) and to test the effect of paroxetine on visual cortex activity. Pregnant mice were given a systemic injection of MK-801, and male offspring that did not present schizophrenia-like behaviors in early adulthood were defined as HRMMS. Some of the HRMMS mice were treated with pharmacological agents beginning at 4 weeks of age. After 4 weeks of treatment with risperidone and/or paroxetine, two-photon calcium imaging was performed to analyze the primary visual cortex activity. The sucrose preference test and the prepulse inhibition (PPI) apparatus test were used to assess the cognitive and behavioral performance. HRMMS mice with or without risperidone treatment had impairments in the primary visual cortex as observed by reduced neuronal calcium activity. Risperidone plus paroxetine and paroxetine alone treatments increased the neuronal calcium activity in the primary visual cortex. Notably, the neuronal calcium activity was higher in mice treated with paroxetine alone. Treatment with paroxetine alone also improved the cognitive and behavioral performance better than treatment with risperidone plus paroxetine. Our pioneering animal model showed that treatment with paroxetine alone improves visual cortex impairments in HRMMS mice better than treatment with risperidone plus paroxetine, indicating that antipsychotics cannot normalize visual cortex impairments.