Furthermore, similar odor-specific modulation of mitral cell activity was observed when mice experienced odors in their home cage, or when mice were tested with odors with a lower concentration, indicating that the plasticity is independent of our imaging conditions (Figures S5 and S6). The odor-specific reduction in the responses of mitral cell populations could reflect two different mechanisms. First, the mitral cells that preferentially Nutlin-3a supplier respond to experienced odors might become less responsive to all odors (gain decrease), in which case experience would not lead to a change in their odor tuning properties. Alternatively, experience could selectively reduce the mitral cell responses

to the experienced odor set, which would modify the odor tuning of individual cells. To distinguish between these two possibilities, we examined the tuning properties of mitral cells that responded to both the

experienced and less-experienced odor sets. Remarkably, we observed that individual mitral cells show experience-dependent changes in odor tuning. After odor set A experience, many selleck chemicals llc cells showed decreased responsiveness specifically to set A odors, while maintaining responsiveness to set B odors (Figure 4F). This was apparent as a specific modulation of the odor tuning curves of individual cells (obtained from the seven tested odors in which odors from the two sets are rank ordered based on responses of individual cells). After experience, odors that generated the strongest responses were shifted toward those that were less experienced (Figure 4G). This specific shift in tuning was consistently observed when CI values were determined for Mannose-binding protein-associated serine protease the experienced and less-experienced odor sets for all individual cells (Figure 4H). In terms of ensemble coding, odor

classification by mitral cell ensembles was equally efficient before and after experience-dependent plasticity (Figure 4I). What effect does experience have on granule cells? To address this question, we imaged granule cell activity in a separate set of animals during the same 7 day odor experience protocol. Similar to mitral cells, we found that responses of individual granule cells also decreased specifically to experienced odors (Figure S7), even though the effect of experience was smaller in granule cells compared to mitral cells (the reduction in the fraction of responsive cells was 70.0% ± 4.3% for mitral cells versus 38.4% ± 6.5% for granule cells, p < 0.001). The reduction in granule cell activity is not unexpected given the fact that mitral cells are the major source of excitation onto this class of interneurons and suggests that the experience-dependent plasticity of mitral cell responses is unlikely to reflect a global increase in the activity of granule cells.