Second-order olfactory-mediated fear-potentiated startle.
Recently, we reported that discrete (4-sec) olfactory cues paired with footshock serve as effective conditioned stimuli (CSs) for potentiating the acoustic startle response in rats using the fear-potentiated startle paradigm. Because odors are such salient cues for the rat, and because of the robust olfactory conditioning observed previously, the current studies investigated second-order fear conditioning using olfactory and visual cues. In Experiments 1 and 2, we used a small number of first-order and second-order training trials on separate days to investigate second-order fear-potentiated startle. Significant potentiated startle was observed in animals receiving Paired/Paired training in both studies, but surprisingly, control animals in the Unpaired/Paired group (Exp. 1) also showed significant potentiated startle to a light S2 at testing. These findings are addressed in the Discussion. Overall, the results of both experiments suggest that olfactory cues serve as efficient S1 and S2 stimuli in second-order fear-potentiated startle paradigms when only a small number of first and second-order training trials are presented.
Paschall
Gayla Y
GY
Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia 30322, USA. gpaschall@aol.com
Davis
Michael
M
D000818:Animals; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D005239:Fear / Q000502:physiology*; D007858:Learning / Q000502:physiology; D008297:Male; D009812:Odorants; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology