Spared Motivational Modulation of Cognitive Effort in a Maternal Immune Activation Model of Schizophrenia Risk

Maternal immune activation (MIA) during gestation is a significant risk factor for development of schizophrenia and other neurodevelopmental diseases. In animal models of this risk factor, MIA during pregnancy can produce offspring that recapitulate certain aspects of the behavioral and neurophysiological impairments seen in schizophrenia. Here, the authors tested the effect of polyinosinic-polycytidylic acid (poly I:C)-induced MIA in a task that explicitly assays the interaction between motivation and cognition. In our paradigm, discrimination accuracy during a sustained-attention task is differentially impacted by environmental cues that signal the probability of reward for accurate performance. Cognition-motivation interactions are implicated in producing functional impairments in patients. Therefore, to the extent that this MIA model recapitulates such impairments, the authors predicted impaired ability of reward-associated signals to modulate cognitive performance in MIA rat offpsring. Adult offspring of dams in which MIA was induced displayed impaired prepulse inhibition relative to controls, verifying a functional effect of poly I: C induction. Despite this deficit, there were no differences between MIA and control rats in any aspects of task learning or performance, including under extinction and reacquisition conditions. These results indicate that MIA spares functioning of some of the cognitive, motivational, and decision-making processes that are impacted in schizophrenia and suggest that MIA as an isolated manipulation does not model the full range and nuance of the cognitive and motivational impairments in the disease. The authors suggest that some aspects of the functional impairment in schizophrenia and other neurodevelopmental diseases may be better modeled using multiple "hit" models of disease risk.