Odor-related bulbar EEG spatial pattern analysis during appetitive conditioning in rabbits.

Mildly thirsty rabbits were classically conditioned by reinforcement with water to give a discriminative licking response to the presentation of odors. The jaw movement component of the licking conditioned response (JM CR) was elicited only by the reinforced odor; an increase in the relative frequency of sniffing (RR CR) occurred to both reinforced (CS+) and nonreinforced (CS-) odors. Oscillatory electroencephalographic bursts of high-frequency (40-80 Hz) potentials were recorded epidurally from the lateral olfactory bulb with 64-electrode arrays (8 X 8, 3.5 X 3.5 mm) chronically implanted. Emphasis was on comparing bursts during odor presentation with bursts preceding odor arrival on each trial. A "detection" burst was characterized as occurring immediately after odor arrival and before the sniff response. "Discrimination" bursts occurred during the RR CR and before the JM CR onset. Significant air-odor burst differences (together with sniffing) occurred through up to six sessions for both CS+ and CS- odors for "discrimination" bursts but not for "detection" bursts.