Cosyne 2008 Workshops
March 3-4, 2008
Snow Bird, Utah
Speaker Name
Maxim Bazhenov, Salk Institute for Biological Studies, La Jolla, CA
Talk Title
Control of sparseness of odor representations in the insect olfactory system
Talk Abstract
Neural circuits exploit numerous strategies for encoding information. Although the functional significance of individual coding mechanisms has been investigated, ways in which multiple mechanisms interact and integrate are not well understood. The locust olfactory system, in which dense, transiently synchronized spike trains across ensembles of antenna lobe (AL) neurons are transformed into a sparse representation in the mushroom body (MB, a region associated with memory), provides a well-studied preparation for investigating the interaction of multiple coding mechanisms. Recordings made in vivo from the insect MB demonstrated highly specific responses to odors in Kenyon cell (KCs). Typically, only a few KCs from the recorded population of neurons responded reliably when a specific odor was presented. Different odors induced responses in different KCs. Using computer models of the locust olfactory system, we proposed that spike-timing dependent plasticity (STDP) may control and tune synaptic weights of inputs to the mushroom body to ensure the specificity of KCs’ responses to familiar or meaningful odors. Activity-dependent plasticity drove the observed specificity, reliability and expected persistence of odor representations, suggesting a role for plasticity in information processing.
