First author: Tóth, Attila (poster)
Poster board D59 - Sun 04/07/2010, 14:30 - Hall 1
Session 053 - Rhythm & pattern generation 1
Abstract n° 053.11
Publication ref.: FENS Abstr., vol.5, 053.11, 2010
||Tóth A., Hajnik T. & Détári L.
||Eotvos Univ., Dep. Phys. and Neurobiol., Budapest, Hungary
||Cholinergic modulation of the slow cortical rhythm in urethane-anesthetized rats
||Slow cortical rhythm (SCR) is a rhythmic alteration of active (UP) and silent (DOWN) epochs in cortical cells. In urethane anesthesia, SCR is characterized by the alternation of almost iso-electrical EEG periods and low-frequency, high-amplitude shifts with superimposed high-frequency activity (UP shifts). In the present experiments, SCR was recorded by 16-pole vertical electrode array from the hindlimb area of the somatosensory cortex in urethane-anesthetized rats. Multiple unit activity (MUA) was also recorded from the close proximity of the recording array. Cholinergic drugs were administered topically near the location of the recording electrode to examine the involvement of the cholinergic system in the SCR. Low dose (10 mM solution) of the muscarinic antagonist atropine did not cause significant changes in the EEG delta power (0-3 Hz) or in the MUA parameters. Higher dose of atropine (100 mM solution) decreased the delta power in the supra- as well as in the infragranular cortical layers. Coherence between the ipsi- and contralateral EEG decreased in the delta (0-3 Hz) band and increased in the beta (20-48 Hz) band. Number of the UP shifts exceeding a pre-defined threshold also decreased in the supra- as well as in the infragranular layers. The cholinergic agonist carbachol (32 mM solution) decreased the delta power (0-3 Hz) in the supragranular layers, EEG coherence in the delta band (0-3 Hz) and the number and amplitude of the UP shifts. The cholinesterase inhibitor physostigmine (13 mM solution) decreased the delta power in the supra- as well as in the infragranular layers. Number and amplitude of the UP shifts also decreased. These changes were associated with a significant reduction of the MUA. The nicotinic agonist nicotine (1 mM solution) did not affect the SCR.
These results suggest that cholinergic system may influence the SCR on a complex way in which muscarinic mechanisms seem to be more important.
Supported by OTKA grant (K 68445).
||D - Sensory and motor systems
Rhythm and pattern generating circuits / Control, afferent and descending
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