Short-Term Plasticity in Auditory Cortical Circuit Evoked by Monetary Incentive Delay Task

Abstract

To choose optimally, people must consider both the potential value and the probability of a desired outcome. This idea is reflected in the expected value theory, which considers both the potential value of different courses of action and the probability that each action will lead to a desired outcome. Accordingly, during decision-making people choose an alternative with the highest expected value. The dominant neurobiological models of decision-making assume that the sensory inputs to the decision-making neural networks are stationary. However, many cognitive studies have demonstrated experience-induced plasticity in the primary sensory cortex, suggesting that repeated decisions could modulate the sensory processing. We investigated experience-induced plastic changes in the neural representation of the acoustic cues coding different expected values using a repeated monetary incentive delay task (MID-task; Knutson et al., 2005). Subjects participated in two extensive sessions of an audio-version of the MID-task. Next, we investigated electrophysiological correlates of the experience-induced plasticity of the primary auditory cortex by comparing the mismatch negativity (MMN) component before and after the MID-task sessions. We found that after extensive MID-task training, the stimuli with largest expected value evoked larger MMN responses (as compared to the baseline oddball session) that probably reflects a more fine-grained stimulus discrimination of highly valued stimuli. After extensive MID-task training acoustic cues coding intermediate expected values evoked larger P3a component (as compared to the baseline oddball session), that can indicate a stronger involuntary attention switching toward moderately valued stimuli. Overall, our results show that continuing valuation during the MID-task evokes a short-term plastic changes in the auditory cortices associated with the improved stimulus discrimination and the involuntary attention towards auditory cues with the high expected value.