Orbitofrontal cortical circuitry mediating post-decision confidence reports

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How confident are you in the decision you just took? We are readily able to answer this question, providing an estimate of our certainty that the choice we made was correct. Here I propose to study the neural underpinnings of such confidence reports by combining psychophysical tools in rats with novel optogenetic techniques allowing for recording and manipulating the activity of identified neural circuits in the brain. In psychophysical experiments, rats learn to make a choice about the identity of a sensory stimulus by entering a choice port, in which they have to wait for a delayed reward. Rats express their confidence in the choice by the amount of time they are willing to wait for a reward before leaving the choice port, providing a post-decision confidence report. Previous work has implicated the orbitofrontal cortex (OFC), a sub region of frontal cortex, in mediating confidence reports in rats. However, it is unknown how different cell types present in OFC form the neural circuitry underlying confidence-guided behaviors. I aim to determine this circuitry in three steps. First I will identify the projection cell types in OFC by mapping the projections from OFC to subcortical areas using viral tracers. Second I will electrically record the activity of single neurons from identified cell types in OFC to determine the information they carry during post-decision confidence reports. Neurons will be identified using optogenetic methods by optically activating light-sensitive channels in defined cell types during electrophysiological recordings. Finally, using the same optogenetic approach, I will perturb the activity of OFC cell types using optical stimulation or inhibition to assess the causal contribution of OFC cell types in driving confidence-guided decisions. I expect that this proposal will uncover the circuitry mediating decision confidence in rats and contribute in resolving the diversity of neural responses observed in frontal cortex by determining the behavioral correlates of distinct cell types.