Changes in Spatial Patterns of Rabbit Olfactory EEG with Conditioning to Odors

TLDR

Epidural 8×8 electrode arrays were implanted on rabbit olfactory bulbs, and conditioned responses to a warning odor paired with shock were elicited while EEG bursts were recorded and displayed as amplitude contour maps. Contour maps showed rabbit‑specific active foci whose shape and location changed only during odor conditioning, not with visual or auditory cues, indicating that spatial patterns are governed by conditioning history rather than stimulus mapping. Implications for human EEG are briefly discussed.

Abstract

ABSTRACT Electrode arrays (8 × 8, 3.5 × 3.5 mm) were implanted epidurally on the olfactory bulbs of rabbits for EEG recording. The rabbits were trained to give a conditioned response to a warning odor paired with an electric shock. EEGs were recorded and edited, and representative ERG bursts with odor and preceding the odor were selected for measurement. Each burst was displayed in a contour map of amplitude. The contour maps revealed active EEG foci in the bulb with size, shape and location unique to each rabbit. Changes in shape and location took place only during familiarization and during training, when a warning odor was paired with the aversive stimulus. The EEG spatial patterns did not change when visual or auditory stimuli were used as CS. EEG spatial patterns did not reflect conformal mapping of odor stimulus to neural activity response, but were determined by state variables of the animal related to olfactory conditioning history. The implications for human EEG are briefly discussed.