Who decodes information contained across synchronized and oscillatory spike trains?
Contents
The Neural Code Problem
The role of temporal coding remains controversial
Starring...
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 locust’s 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 neurons’ 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
References
Email: alex@caltech.edu
Home Page: http://www.cco.caltech.edu/~alex
Other information: See Nature 395:693-698 for more information.