Project 2 - Top-down control of value-based decision-making

Lead Investigator: Thomas Elston

Potential Treatments: Depression, addiction, schizophrenia, Parkinson's.

Many neuropsychiatric disorders involve compromised decision-making. Understanding the neural mechanisms underlying these impairments is difficult since it is increasingly clear that multiple cognitive processes are involved. Recent studies have demonstrated two distinct process: value-guided attentional capture, which rapidly orients attention towards high value options, and slower, deliberative decision-making, which involves a more precise evaluation of the available options. These results raise the question as to why a slow, deliberative system is needed if the rapid, phasic signal can identify the more valuable option. One possibility is that the deliberative system is required when top-down goals inhibit more automatic responses to valuable stimuli. This may be particularly relevant in processes such as recovery from addiction. To investigate this, we have developed novel decision-making tasks in which the value of options is determined by a high-level abstract rule. Our prediction is that cortical areas encode the rules and inhibit faster, automatic value responses in the striatum via a synchronization of the theta oscillation between the two structures. To causally test this mechanism, we will examine the effect of closed-loop theta microstimulation in prefrontal cortex on the performance of the task, whereby we use the theta oscillation to control the application of microstimulation so that the stimulation occurs at a specific phase of the oscillation.

Dysfunction of frontostriatal circuits occurs in several neuropsychiatric disorders, including schizophrenia, major depression, and post-traumatic stress disorder. Our goal is to develop devices that will interact with neural circuits in a principled way to treat neuropsychiatric disorders, such as using neural activity to detect symptoms and microstimulation to intervene. An impediment to this approach is that the neural coding in these circuits remains poorly understood. The current project aims to understand the dynamics of these neural signals to help lay the groundwork for future potential therapeutic approaches based on closed-loop microstimulation.