Date of Award
12-20-2024
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Economic choices entail computing the values of different options and then making choice by comparing values. Work in primates and rodents has shown that these mental processes rely on the OFC. Neurophysiology studies identified in OFC distinct groups of neurons encoding the value of individual options, the binary choice outcome, and the chosen value. These variables capture both the input and the output of the decision process, suggesting a decision circuit existing in OFC. A primary challenge for the field is to assess the structure and mechanisms governing this circuit. A first fundamental question is whether the circuit is stable over long periods of time. The second question is whether the building block of this circuit, i.e., different groups of cells, are anatomically distinct – e.g., located in different cortical layers. To address these two issues, we used two-photon calcium imaging to record from the OFC of mice choosing between different juice rewards. Confirming neurophysiology results, different groups of cells encoded individual offer values, their spatial configuration, the choice outcome, and the chosen value. We recorded longitudinally from individual neurons for up to 20 weeks. And we manually classified neurons from L2/3 and L5. For each cell and each pair of sessions, we compared the activity profiles using cosine similarity, and we assessed whether the cell encoded the same variable in both sessions. These analyses demonstrated a high degree of stability in the activity profiles and consistency in the functional properties of individual neurons. Furthermore, the classification of neurons based on the cortical layer (L2/3 or L5) showed that (i) all groups of neurons populate multiple cortical layers, but (ii) good-based offer values and offer spatial configurations are more represented in L2/3, while (iii) spatial configuration-based offer value and chosen outcome are more represented in L5. These findings shed light on the circuit structure of OFC and lay the ground to dissect the neuronal mechanisms underlying economic choices.
Language
English (en)
Chair
Camillo Padoa-Schioppa
Committee Members
Timothy Holy; Andreas Burkhalter; Barani Raman; Yao Chen