Odor coding beyond the first breath: adaptation and memory in the olfactory bulb (ISOT XVI)
A poster I will present at ISOT XVI in Stockholm, June 24, 2012. As this is a poster, there is little text explaining figures, but details of experiments can be found on my blog, under "unpublished data": http://www.trailofpapers.net/search/label/%22unpublished%22%20data
Mitral cells in the olfactory bulb of mammals encode odors dynamically via short, phasic responses throughout the breathing cycle. Less attention has been paid to how dynamic these responses are between breaths.
To look at the inter-breath dynamics of odor coding, we performed multielectrode recording from the olfactory bulb of awake (and anesthetized) head-restrained mice. We found that the odor code is not stationary, and that individual cells change their response between breaths. On the population level, we show that the first breath is different from each subsequent breath.
We also looked at how odors are coded after the end of odor presentation. We found that individual cells have post-odor responses that can last for seconds. On the population level, this information contains odor- and concentration-specific information. Increasing the length of odor presentation caused longer post-odor responses. To investigate the possibility of network reverberations, we artificially stimulated the olfactory bulb of Thy1-ChR2 mice, and found that stimulation could cause persistent activity for seconds following stimulation. Finally, to show that feedback can come from higher areas, we measured the LFP in the OB of mice with the ipsilateral OB blocked, and found there was still activity.