Distinguishing Medial Temporal Lobe and Prefrontal Cortex Contributions to Approach-Avoidance Conflict in Healthy Controls and Generalized Anxiety Disorder: Insights from Functional Magnetic Resonance Imaging and the Hierarchical Drift Diffusion Model

The ability to arbitrate approach-avoidance (AA) conflict, a cognitive state elicited by simultaneous reward and punishment, is critical for adaptive decision-making. Across translational rodent and human models, AA conflict has been associated with anxiety and is supported by a network of brain regions including the medial temporal lobe (MTL), striatum, and prefrontal cortex (PFC). This work, however, is limited in two respects. (1) Human models employing functional Magnetic Resonance Imaging (fMRI) have historically relied on analyses that fail to disentangle how neural activity relates to decision-making characteristics underlying AA conflict. In Chapter 2, therefore, I applied the Hierarchical Drift Diffusion Model (HDDM), a computational modelling approach, to an AA conflict task administered to healthy controls. I found that PFC regions contributed to inhibition and adjusting response caution, with differential involvement of the anterior cingulate cortex (ACC) and dorsolateral PFC (DLPFC). While the anterior hippocampus (aHPC) supported evidence generation, perirhinal cortex (PRC) activity pointed towards threat perceptual processing and response caution. (2) There has been limited work stressing the mechanisms underlying AA conflict by testing it in samples with anxiety psychopathology, despite anxiety’s integral role in AA conflict in healthy and clinical populations. In Chapter 3, therefore, I collected a second dataset in which individuals with GAD and healthy controls completed a rule-based AA conflict task while undergoing fMRI. Application of the HDDM indicated that the GAD group engaged in faster evidence generation to avoiding conflict. Moreover, theoretically similar constructs (i.e., GAD and depression symptom severity, worry, intolerance of uncertainty) had identical linear relationships with evidence generation to conflict, although the effects of GAD and depression symptom were the strongest. The GAD group showed a general deactivation in the PFC and PRC during conflict, as well as divergent patterns of neural recruitment compared to controls in the ACC, DLPFC, striatum, aHPC, and PRC during evidence generation, response caution, inhibition, and optimization of cognitive processing. I spotlight the differing contributions of the PFC and MTL to AA conflict evidence generation and regulation and provide novel evidence that excessive anxiety impairs engagement with the decision-making process at a computational and neural level.

Department dc:contributor.department

Psychological Clinical Science

Year dc:date.issued

2024

Author dc:creator

• Chu, Sonja

Advisors dc:contributor.advisor

• Lee, Andy
• Goghari, Vina

• Approach-Avoidance Conflict
• Computational Modelling
• Functional Magnetic Resonance Imaging
• Generalized Anxiety Disorder

Handle dc:identifier.uri

http://hdl.handle.net/1807/140108

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/140108