Conditioned enhancement of the early component of the rat eyeblink reflex

Neurobiology of Learning and Memory
Y W LamT H Brown

Abstract

Conditioned enhancement of the rat eyeblink reflex was studied using as a response measure the electromyogram (EMG) in the orbicularis oculi (oo) muscle, which is responsible for the active force generating eyelid closure. During a reflex eyeblink, the EMG evidences both a short-latency (R1) and a long-latency (R2) component, mediated by different circuits. The R2 response exhibits several experience- or use-dependent modifications. We were interested in the modifiability of the neurophysiologically simpler R1 response. Experiments were designed to determine whether the R1 response can be enhanced by a conditioned stimulus (CS) that has been explicitly paired with an aversive unconditioned stimulus (US). The R1 response was elicited by electrical stimulation of the supraorbital branch of the trigeminal nerve. Following long-delay conditioning, the CS produced a significant R1 enhancement and latency decrease that were dependent upon explicit CS-US pairings. The CS by itself produced no significant EMG response, consistent with a modulatory rather than additive effect. This is the first demonstration that the R1 response can be associatively modulated. Based on other evidence, we hypothesize that the CS-produced enhancement resu...Continue Reading

Citations

Apr 29, 2004·Behavioral Neuroscience·Derick H Lindquist, Thomas H Brown
Dec 6, 2003·Learning & Memory·Kimberly M Christian, Richard F Thompson

❮ Previous
Next ❯

Related Concepts

Related Feeds

Amygdala and Midbrain Dopamine

The midbrain dopamine system is widely studied for its involvement in emotional and motivational behavior. Some of these neurons receive information from the amygdala and project throughout the cortex. When the circuit and transmission of dopamine is disrupted symptoms may present. Here is the latest research on the amygdala and midbrain dopamine.

Amygdala: Sensory Processes

Amygdalae, nuclei clusters located in the temporal lobe of the brain, play a role in memory, emotional responses, and decision-making. Here is the latest research on sensory processes in the amygdala.