Concentration invariant odor identity coding

Summary

Date: 
November 17, 2015 - 12:00pm
Location: 
NW 243
About the Speaker
Name: 
Dmitry Rinberg (NYU)

Humans can easily identify visual objects independent of view angles and lighting, individual words in speech independent of volume and pitch, and smells independent of their concentrations. The computational principles and underling neural mechanisms responsible for invariant object recognition remain mostly unknown. Olfaction, being one of the most genetically tractable, anatomically compact and very relevant to rodent behavior sensory system, presents a great opportunity to explore and model such mechanisms.

Here we propose a computational principle of concentration invariant odor identification based on temporal ranking of receptor activation. We assume that only a small population of first activated receptor neurons is fully responsible for odor identification. To test this model, which we called ‘primacy coding’, we performed optogenetic masking experiments, and demonstrated the relevance of short temporal interval at the beginning of the sniff cycle for odor identification. We also observed the signature of primacy coding at the level of the next after receptor neurons cell, mitral/tufted cells. We propose a simple model of how such code can be read by a cortex and discuss the relevance of primacy coding for known olfactory psychophysical phenomena.