mushroom bodies [40,41]. The conservation of inhibitory
mechanisms from fly to mouse points to a central role for
distributed and sparse coding in higher order sensory
processing regions. These observations provide a framework
for further analysis into the role of experience and
learning in shaping these sparse codes. In rodents,
plasticity in the connections between small numbers of
active piriform neurons and in their connections with
other associational brain regions may give rise to robust
odor-driven behaviors.