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.I Physiology (Paris) (1996) 90. 353-360 OElsevier, Paris

Summary: .I Physiology (Paris) (1996) 90. 353-360
OElsevier, Paris
Possible involvement of neuromodulatory
systems in cortical Hebbian-like plasticity
E Ahissa?, S Haidarliua, DE Shulzb
*De artment of Neurobiology, The Weimann Institute of Science. Rehotsot 76100, Israel;
Equrpe Cognisciences. Institut Alfred-Fessard. CNRS. 91190 Gif-sur-Yvette, France
Summary-Plasticity of neuronal covariances (functional plasticity) is controlled by behavior (Ahissar et al (1992) Science 257, 1412-1415).
Whether this behavioral control involves neuromodulatory systems was tested by examining the effect of acetylcholine (ACh) and noradrenaline
(NE) on functional plasticity in anesthetized animals and by comparing the effects of these neuromodulators in an anesthetized preparation
to that of behavior in awake animals. Local iontophoretic applications of these drugs during manipulations of activity covariance in guinea
pig auditory cortex did not mimic the behavioral control of functional plasticity that was previously observed in awake monkeys. Thus, the
hypotheses according to which these neuromodulators control functional plasticity independent of their concentration and time of release were
not supported by our data. The significant plasticity induced nevertheless, by some of the conditionings in the presence of ACh and NE,
suggests that factors, other than those that were experimentally controlled, could regulate this plasticity. These factors could be among others
the timing of drug(s) applications relative to the conditioning time, the local concentrations of the drug(s) and/or the site of application with
respect to the relevant synapses.
acetylcholine I noradrenaline I attention I auditory cortex I cross-correlation I neuromodulator I Hehbian synapse / synaptic plasticity


Source: Ahissar, Ehud - Department of Neurobiology, Weizmann Institute of Science
Shulz, Daniel - Unité de Neurosciences Information et Complexité


Collections: Biology and Medicine