title: Unit responses changing with behavioral outcome in the olfactory bulb of unrestrained rats.
abstract: The unit activity of 16 neurons, including 12 likely mitral cells, was recorded in one olfactory bulb of 5 unrestrained rats, together with contralateral multiunit activity, and respiratory rhythm. The hungry animals were stimulated either by food odor (F) learned as a signal for one available food pellet, or by isoamyl acetate (IA), presented randomly. Eighty-four sequences, each with one stimulation, were analyzed to determine how the odors modified unit, multiunit and respiratory activities. The stimulation could change the variance and/or mean of the unit discharge and its correlation with the respiration phase or frequency or with multiunit activity. Besides the IA sequences, F+, F= and F-situations had to be distinguished, when the pellet was eaten spontaneously, accepted if presented at mouth or refused actively. The neuron responses were reproducible, in a given situation, but their occurrence within a series of identical stimuli was unpredictable from the controlled or observed events. The positive mitral responses were more probable in the F+ and F= than in the F-sequences; they were then associated with multiunit and respiratory activation. Response criteria and neuron typology are discussed. The functional involvements of neuron variability and modulation with internal state are considered.
mesh_terms: D000818:Animals; D001143:Arousal / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology; D004193:Discrimination Learning; D004292:Dominance, Cerebral / Q000502:physiology; D005071:Evoked Potentials; D006815:Hunger / Q000502:physiology; D008297:Male; D009474:Neurons / Q000502:physiology; D009830:Olfactory Bulb / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration; D012903:Smell / Q000502:physiology*