The amygdala is essential for the expression of conditional hypoalgesia. Behav Neurosci 1992 Jun;106(3):518-28
Date
06/01/1992Pubmed ID
1319714DOI
10.1037//0735-7044.106.3.518Scopus ID
2-s2.0-0026747754 (requires institutional sign-in at Scopus site) 191 CitationsAbstract
Two experiments were conducted to determine whether the amygdala is involved in the performance of hypoalgesia as a Pavlovian conditional response. Rats were trained by pairing a distinctive observation chamber with a series of 3 footshocks. Rats were returned to the chamber 24 hr later, and the time spent engaged in freezing behavior and stereotyped behavioral reactions to a subcutaneous injection of dilute formalin was recorded. Sham-operated subjects spent large amounts of time freezing and were hypoalgesic on the formalin test in relation to nonshocked controls. Small electrolytic lesions of the amygdala eliminated both defensive freezing behavior and hypoalgesia without altering baseline reactions to formalin. Larger lesions made with ibotenic acid produced a similar pattern of results implicating neurons intrinsic to the amygdala. These results indicate that the amygdala may represent a forebrain site critical for the activation of descending antinociceptive systems in response to certain classes of environmental stressors.
Author List
Helmstetter FJAuthor
Fred Helmstetter PhD Professor in the Psychology / Neuroscience department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
AmygdalaAnimals
Arousal
Brain Mapping
Conditioning, Classical
Electroshock
Fear
Female
Motor Activity
Neural Pathways
Neurons
Nociceptors
Rats
Sensory Thresholds
Social Environment
Synaptic Transmission
