Elsevier

Brain Research

Volume 480, Issues 1–2, 20 February 1989, Pages 210-218
Brain Research

Research report
Auditory cortex lesions prevent the extinction of Pavlovian differential heart rate conditioning to tonal stimuli in rabbits

https://doi.org/10.1016/0006-8993(89)91584-9Get rights and content
Under a Creative Commons license
open archive

Abstract

The present study examined the role of the auditory cortex in the extinction of differentially conditioned heart rate (HR) responses in rabbits. Lesions were placed bilaterally in wither the auditory cortex or the visual cortex. Three days after recovery from surgery, the auditory cortex lesion group and the visual cortex lesion control group were habituated to the tonal conditioned stimuli (CSs), and then given 2 days of Pavlovian differential conditioning (60 trials per day) in which one tone (CS+) was always paired with the unconditioned stimulus and another tone (CS−) was never paired with the uncondition stimulus. Animals that had demonstrated reliable differential conditioning (CS+ response at least 5 beats greater than the CS− response) were placed on an extinction schedule for 7 days. The extinction schedule was identical to the differential conditioning schedule with the exception that shock never followed the CS+. The results of the study indicate that auditory cortex lesions prevent the extinction of differential bradycardia conditioned responses (CRs) to tonal CSs. Whereas the bradycardia responses to the CS+ quickly extinguished in the group that had control lesions in the visual cortex, the auditory cortex lesion group continued to exhibit significantly larger bradycardiac HR CRs to the CS+ relative to the CS− during all 7 days of extinction. These results suggest that the animals in the auditory cortex lesioned group did not inhibit responses to a previously reinforced stimulus (i.e. CS+) as well as animals with control lesions in the visual cortex.

Keywords

Auditory cortex
Bradycardia
Differential Pavlovian conditioning
Extinction
Heart rate
Rabbit

Cited by (0)

Present address: Department of Psychology, Krebs Hall, Room 113, University of Pittsburgh at Johnstown, Johnstown, PA 15904, U.S.A.