TY - JOUR T1 - Sparse Odor Coding in Awake Behaving Mice JF - The Journal of Neuroscience JO - J. Neurosci. SP - 8857 LP - 8865 DO - 10.1523/JNEUROSCI.0884-06.2006 VL - 26 IS - 34 AU - Dmitry Rinberg AU - Alex Koulakov AU - Alan Gelperin Y1 - 2006/08/23 UR - http://www.jneurosci.org/content/26/34/8857.abstract N2 - Responses of mitral cells represent the results of the first stage of odor processing in the olfactory bulb. Most of our knowledge about mitral cell activity has been obtained from recordings in anesthetized animals. We compared odor-elicited changes in firing rate of mitral cells in awake behaving mice and in anesthetized mice. We show that odor-elicited changes in mitral cell firing rate were larger and more frequently observed in the anesthetized than in the awake condition. Only 27% of mitral cells that showed a response to odors in the anesthetized state were also odor responsive in the awake state. The amplitude of their response in the awake state was smaller, and some of the responses changed sign compared with their responses in the anesthetized state. The odor representation in the olfactory bulb is therefore sparser in awake behaving mice than in anesthetized preparations. A qualitative explanation of the mechanism responsible for this phenomenon is proposed. ER -