The way an odor is experienced during aversive conditioning determines the extent of the network recruited during retrieval: a multisite electrophysiological study in rats.
Journal of Neuroscience. 2009-08-19; 29(33): 10287-10298
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1. J Neurosci. 2009 Aug 19;29(33):10287-98. doi: 10.1523/JNEUROSCI.0505-09.2009.
The way an odor is experienced during aversive conditioning determines the extent
of the network recruited during retrieval: a multisite electrophysiological study
Chapuis J(1), Garcia S, Messaoudi B, Thevenet M, Ferreira G, Gervais R, Ravel N.
(1)Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche
(UMR) 5020 Neurosciences Sensorielles Comportement Cognition, Université Lyon 1,
Université de Lyon, Lyon, France.
Recent findings have revealed the importance of orthonasal and retronasal
olfaction in food memory, especially in conditioned odor aversion (COA); however,
little is known about the dynamics of the cerebral circuit involved in the
recognition of an odor as a toxic food signal and whether the activated network
depends on the way (orthonasal vs retronasal) the odor was first experienced. In
this study, we mapped the modulations of odor-induced oscillatory activities
through COA learning using multisite recordings of local field potentials in
behaving rats. During conditioning, orthonasal odor alone or associated with
ingested odor was paired with immediate illness. For all animals, COA retrieval
was assessed by orthonasal smelling only. Both types of conditioning induced
similarly strong COA. Results pointed out (1) a predictive correlation between
the emergence of powerful beta (15-40 Hz) activity and the behavioral expression
of COA and (2) a differential network distribution of this beta activity
according to the way the animals were exposed to the odor during conditioning.
Indeed, for both types of conditioning, the aversive behavior was predicted by
the emergence of a strong beta oscillatory activity in response to the odor in
the olfactory bulb, piriform cortex, orbitofrontal cortex, and basolateral
amygdala. This network was selectively extended to the infralimbic and insular
cortices when the odor was ingested during acquisition. These differential
networks could participate in different food odor memory; these results are
discussed in line with recent behavioral results that indicate that COA can be
formed over long odor-illness delays only if the odor is ingested.
PMID: 19692603 [Indexed for MEDLINE]