Specific features of fear conditioning expression in active and passive rabbits
Pavlova, I.V.; Rysakova, M.P.
Rossiiskii Fiziologicheskii Zhurnal Imeni I.M. Sechenova 99(11): 1250-1264
2013
ISSN/ISBN: 0869-8139 PMID: 25427379 Document Number: 665772
The active and passive rabbits selected previously on the basis of their behavior in open field and light-dark test, were subjected to fear conditioning using pairing light (4 s) with footshocks (10 Hz, 0.5 s). Heart rate and respiration rate were measured during the classical fear conditioning. Heart rate and respiration rate decreased in response to light before footshock in case of passive-defensive reaction. There were no heart rate and respiration rate reduction in the course of the active defensive reaction. In active rabbits, as compared to passive ones, the frequency of active locomotors reactions and heart rate were higher, the decrease of respiration rate to light was observed at later stages of training, and the detected bradycardia was not stable. Thus, based upon vegetative characteristics, the active rabbits had lower level of fear than passive ones. The active or passive behavioral strategies of animals were preserved during fear conditioning.