ERIC Number: EJ921175
Record Type: Journal
Publication Date: 2011-Apr
Abstractor: As Provided
Reference Count: 0
Impact of Infralimbic Inputs on Intercalated Amygdale Neurons: A Biophysical Modeling Study
Li, Guoshi; Amano, Taiju; Pare, Denis; Nair, Satish S.
Learning & Memory, v18 n4 p226-240 Apr 2011
Intercalated (ITC) amygdala neurons regulate fear expression by controlling impulse traffic between the input (basolateral amygdala; BLA) and output (central nucleus; Ce) stations of the amygdala for conditioned fear responses. Previously, stimulation of the infralimbic (IL) cortex was found to reduce fear expression and the responsiveness of Ce neurons to BLA inputs. These effects were hypothesized to result from the activation of ITC cells projecting to Ce. However, ITC cells inhibit each other, leading to the question of how IL inputs could overcome the inter-ITC inhibition to regulate the responses of Ce neurons to aversive conditioned stimuli (CSs). To investigate this, we first developed a compartmental model of a single ITC cell that could reproduce their bistable electroresponsive properties, as observed experimentally. Next, we generated an ITC network that implemented the experimentally observed short-term synaptic plasticity of inhibitory inter-ITC connections. Model experiments showed that strongly adaptive CS-related BLA inputs elicited persistent responses in ITC cells despite the presence of inhibitory interconnections. The sustained CS-evoked activity of ITC cells resulted from an unusual slowly deinactivating K[superscript +] current. Finally, over a wide range of stimulation strengths, brief IL activation caused a marked increase in the firing rate of ITC neurons, leading to a persistent decrease in Ce output, despite inter-ITC inhibition. Simulations revealed that this effect depended on the bistable properties and synaptic heterogeneity of ITC neurons. These results support the notion that IL inputs are in a strategic position to control extinction of conditioned fear via the activation of ITC neurons.
Descriptors: Stimulation, Inhibition, Fear, Brain Hemisphere Functions, Biology, Physiology, Cognitive Processes, Cytology, Responses, Simulation, Conditioning
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A