By studying the neural basis of this form of sensory processing in relatively simple animals such as insects, we hope to discover basic principles that may apply to animals in general. As in the locust, we find evidence of odor-evoked oscillating, coherent neural activity in both the cockroach and the honeybee. Cross- correlation diagrams for LFP and PN activity. Odorants elicit oscillations in the local field potential and intracellularly-recorded membrane potentials of antennal lobe neurons. Oscillations are 20-30 Hz.
Oscillations generally increase in intensity over the first few odorant presentations.
Cockroaches appear to employ an ongoing, background synchrony that is intensified by odor presentation. Removing the antennae, illustrated in the next figure, abolishes evidence for this ongoing synchrony, suggesting it may be caused by detection of background room odorants. These results suggest that oscillatory neural synchrony is a common feature of olfaction in insects. Comparable odorant-induced oscillations have previously been observed in vertebrate and molluscan preparations. Many important issues in olfactory processing and memory can be addressed only in a preparation suitable for combined cellular and behavioral experiments.