The mammalian olfactory system shows many types of sensory and perceptual processing accompanied by oscillations at the level of the local field potential, and much is already known about the cellular and synaptic origins of these markers of coherent population activity. Complex, but chemotopic input patterns describe the qualitative similarity of odors, but animals can discriminate even very similar odorants. Coherent population activity signified by oscillations may assist the animals in discrimination of closely related odors. Manipulations to olfactory bulb centrifugal input and GABAergic circuitry can alter the degree of gamma (40-100 Hz) oscillatory coupling within the olfactory bulb, affecting animals’ ability to discriminate highly overlapping odors. The demands of an odor discrimination can also enhance gamma oscillations, but this may depend on the cognitive demands of the task, with some tasks spreading the processing over many brain regions, accompanied by beta (15-30 Hz)...
Leslie M. Kay