title: Evidence for a cholinergic mechanism of "learned" changes in the responses of barrel field neurons of the awake and undrugged rat.
abstract: Due to its functional importance and its large and highly differentiated central projections, the vibrissal system of rodents is a prime object for the study of sensory plasticity, especially at the cortical level: the representation of vibrissae in the "barrel field", a part of the somatic cortex, is exceptionally precise and is susceptible to experience-induced changes. In a previous series of experiments, we found that a sensory-sensory conditioning procedure, pairing two vibrissal stimulations, produces significant changes in responses of single neurons of the barrel field in the chronic awake and undrugged rat: (1) the appearance of an excitatory response to a stimulus that was ineffective before pairing ("conditioned response"); (2) the modifications of pre-existing responses consisting of the suppression of afferent inhibition and the appearance of long-latency excitatory components. We report here that the micro-iontophoretic application of atropine abolishes "conditioned responses" and restores afferent inhibition. Acetylcholine facilitates an enlargement of the receptive field and induces a sustained mode of discharge to stimuli. These data provide a new and direct support to the hypothesis that cholinergic mechanisms are involved in the sensory cortex plasticity.
authors.affiliation: Laboratoire de Psychophysiologie, Université Paris 7, France.
authors.forename: J
authors.initials: J
authors.lastname: Delacour
authors.forename: O
authors.initials: O
authors.lastname: Houcine
authors.forename: J C
authors.initials: JC
authors.lastname: Costa
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000187:drug effects / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D051381:Rats; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae
chemical_list: D001285:Atropine; D000109:Acetylcholine