Who decodes information contained across synchronized and oscillatory spike trains?


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Table of Contents

Who decodes information contained across synchronized and oscillatory spike trains?


The Neural Code Problem

The role of temporal coding remains controversial


Why the locust?

The olfactory system of the locust

Physiology of the olfactory system of the locust

PNs respond with different temporal patterns to different odors

PNs assemblies synchronize, creating oscillations in LFP

Odor representation in the AL

Odors are encoded by temporal sequences of spikes in oscillating neural assemblies (Wehr & Laurent, 1996)

Disruption of synchronization impairs fine odor discrimination (Stopfer et al., 1997)

Stimulus reconstruction in the olfactory system

From the locustís point of view

From spikes to odors

A cost-based metric to measure similarity between spike trains

For each spike train, the average distance to spike trains occurring in response to each odor is measured

Each spike train is classified as indicating the odor whose spike trains are closest on average

How much odor information is there in a single neuron?

Where is the effect of desynchronization caused?

Does information withstand desynchronization?

Information in single PNs withstands desynchronization

?-lobe neurons, downstream of synchronizing PNs, respond to odors (MacLeod et al., 1998)

?-lobe neuronsí responses exhibit a loss of odor discrimination after desynchronization

Desynchronization impairs read-out of PN information by downstream neurons

Information flow in the olfactory system: Summary

Some work in progress


Author: Alejandro Backer

Email: alex@caltech.edu

Home Page: http://www.cco.caltech.edu/~alex

Other information:
See Nature 395:693-698 for more information.