Temporal changes in mitral cell response patterns during repeated odor exposure.

The olfactory system of 17 goldfish was stimulated by natural odors, and from 31 mitral cells activity was extracellularly recorded as a response to the stimuli. 40 experiments were available for evaluation because nine of the 31 cells were investigated with respect to two different odors. The aim of this study was to examine the changes of the activity patterns during repeated runs of an experiment. 120 runs were taken in 15 experiments, 40 runs in 25 experiments, and 37 runs in 2 experiments. Nineteen out of the forty recordings showed patterned activities. In ten cases the patterns remained constant in all runs, while pattern changes occurred in nine cases. These changes sometimes happened abruptly after the first run or developed gradually over up to forty runs in other cases. Possible causes of the pattern changes are discussed.