Inhibitory control deficits and ventral attention network alterations linked to apathy in schizophrenia

Individuals with schizophrenia demonstrated impaired inhibitory control and apathy symptoms, which are characterized by a reduction in self-initiated voluntary activities. However, whether deficits in inhibitory control are linked to apathy remains unclear. Here we investigated inhibitory control-related neural networks and associations with interview-based apathy and actigraphy-derived motor activity, an objective measure of apathy. Twenty-three patients with schizophrenia underwent 3T-fMRI scans during Go/No-Go task. Task-related networks were identified via independent component analysis. Behavioral performance was examined using a drift diffusion model. Correlation and regression analyses examined relationships between apathy severity scores, motor activity, behavioral parameters, task-related networks engagement and connectivity. Patients with higher levels of apathy showed reduced motor activity levels, lower overall accuracy rate in inhibitory control, particularly more inhibitory errors, lower Go-condition processing efficiency, and reduced stimulus sensitivity. On the neural level, higher apathy correlated with weaker ventral attention network (vAN) engagement during successful inhibition, and weaker default mode network (DMN) engagement during failed inhibition, although the latter association was influenced by age and depressive symptoms. Stronger left posterior cingulate cortex spatial contribution to DMN and weaker vAN-DMN coupling were associated with higher apathy in patients with schizophrenia. Motor activity levels were unrelated to inhibitory-related networks. Higher apathy in schizophrenia was related to worse inhibitory control performance and decreased vAN and DMN recruitment and connectivity during response inhibition, indicating impairments in sustaining attention on the task and allocating cognitive resources in response to external demands. Dysfunctional neural networks underpinning inhibition may contribute to reduced goal-directed behavior. Motor activity appears to be related to apathy in terms of auto-activation, but not in terms of cognitive inhibitory control.