Conditioning of relative frequency of sniffing by rabbits to odors.

Developed and evaluated an automated procedure for sniff detection in 4 experiments with 21 adult New Zealand white rabbits. The sniff was identified by a brief episode of increased respiratory rate, usually with a well-defined time of onset. It was detected against the background of respiratory activity in Ss simply, reliably, and noninvasively by statistical evaluation of digitized pneumograph records. The basal rate of exploratory sniffing was controlled by familiarization. Upon conditioning to olfactory cues, the rate of sniffing for CS+ increased sharply above the basal rate during the 1st trials and was maintained at high levels by continued reinforcement. During extinction with discrimination between olfactory cues, the rate for CS– fell sharply at first and then more slowly toward the basal rate. With pseudoconditioning, Ss responded to an unpaired odor after several sessions; the rates of response acquisition and extinction and the maintained level of responding were lower than with a paired odor in classical delayed conditioning, and the response was not discriminative in respect to another novel odor given during extinction. The sniff displayed a prominent sensory bias for olfactory cues. The relative frequencies of sniffing and respiratory slowing were measured as CRs by screening procedures with a small computer. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)