The Neural Substrates Supporting the Inhibition of Instrumental Avoidance Behavior

Previous studies have elucidated much of the neural circuitry underlying the acquisition of discriminative avoidance behavior in rabbits, wherein rabbits learn to step in an activity wheel in response to a conditional stimulus (CS+) predictive of a foot shock while learning to avoid another stimulus (CS-) not followed by shock. However, less is know about the neural substrates involved in the inhibition of this behavior, as occurs when a stimulus acquires inhibitory properties and signals response omission. The following thesis aimed to uncover the neural substrates that underlie the inhibition of conditioned responding that occurs during extinction of discriminative avoidance behavior and during the acquisition of conditioned inhibition. The first study tested the hypothesis that the flow of information from the entorhinal cortex through the ventral subiculum to the nucleus accumbens is the pathway that mediates the suppression of conditioned responding in response to novel contextual cues during extinction of discriminative avoidance behavior. The results supported this hypothesis, demonstrating that lesions of the ventral subiculum disrupted the contextual specificity of both extinction behavior and extinction-related neuronal plasticity in the nucleus accumbens. A second study investigated the role of the amygdala in extinction learning by investigating the effects of amygdalar inactivation during extinction in a familiar or novel training context. The findings indicated a role for the amygdala in the contextual specificity of extinction memories and the initiation of extinction-related plasticity in cingulothalamic brain areas. A third study examined the neural correlates of conditioned inhibition by examining neuronal activity during instrumental feature-negative discrimination training. Results favored an early convergence model of conditioned inhibition, in which the encoding of conditioned inhibition manifests early in the stimulus processing stream in sensory and limbic areas.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Neuroscience

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Burhans, Lauren B.

Contributors dc:contributor

• Gabriel, Michael

• Psychology, Behavioral

Language dc:language

eng

Identifier

(MiAaPQ)AAI3182226

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/82500