CPL graduate student Michelle Tong, with contributions by CPL graduate student Shane Peace, published a review article on the mechanisms of learning and memory within olfactory bulb. Most of what is known about olfactory bulb memory mechanisms comes from one-trial learning studies in neonatal rodents (esp. the work of Carolyn Harley, John McLean, and Regina Sullivan). In adult animals, appetitive olfactory learning (including bulbar learning) is more gradual, representational, and statistical in nature, and it is exactly these properties that olfactory memory studies are well suited to investigate.

Tong MT, Peace ST, Cleland TA (2014) Properties and mechanisms of olfactory learning and memory. Front Behav Neurosci. 8:238.   doi: 10.3389/fnbeh.2014.00238.

Abstract:  Memories are dynamic physical phenomena with psychometric forms as well as characteristic timescales. Most of our understanding of the cellular mechanisms underlying the neurophysiology of memory, however, derives from one-trial learning paradigms that, while powerful, do not fully embody the gradual, representational, and statistical aspects of cumulative learning. The early olfactory system—particularly olfactory bulb—comprises a reasonably well-understood and experimentally accessible neuronal network with intrinsic plasticity that underlies both one-trial (adult aversive, neonatal) and cumulative (adult appetitive) odor learning. These olfactory circuits employ many of the same molecular and structural mechanisms of memory as, for example, hippocampal circuits following inhibitory avoidance conditioning, but the temporal sequences of post-conditioning molecular events are likely to differ owing to the need to incorporate new information from ongoing learning events into the evolving memory trace. Moreover, the shapes of acquired odor representations, and their gradual transformation over the course of cumulative learning, also can be directly measured, adding an additional representational dimension to the traditional metrics of memory strength and persistence. In this review, we describe some established molecular and structural mechanisms of memory with a focus on the timecourses of post-conditioning molecular processes. We describe the properties of odor learning intrinsic to the olfactory bulb and review the utility of the olfactory system of adult rodents as a memory system in which to study the cellular mechanisms of cumulative learning.