DIFFERENTIAL OSCILLATORY PROPERTIES OF CHOLINERGIC AND NONCHOLINERGICNUCLEUS BASALIS NEURONS IN GUINEA-PIG BRAIN SLICE

Citation
A. Alonso et al., DIFFERENTIAL OSCILLATORY PROPERTIES OF CHOLINERGIC AND NONCHOLINERGICNUCLEUS BASALIS NEURONS IN GUINEA-PIG BRAIN SLICE, European journal of neuroscience, 8(1), 1996, pp. 169-182
Citations number
57
Categorie Soggetti
Neurosciences
ISSN journal
0953816X
Volume
8
Issue
1
Year of publication
1996
Pages
169 - 182
Database
ISI
SICI code
0953-816X(1996)8:1<169:DOPOCA>2.0.ZU;2-P
Abstract
Evidence has suggested that the nucleus basalis magnocellularis has th e potential to influence the functional state of the cerebral cortex t hrough topographically organized, widespread projections of the cholin ergic cells in that nucleus. It has also been shown that, in addition to the cholinergic neurons, other non-cholinergic magnocellular basal forebrain neurons, some of which have been identified as gamma-aminobu tyric acid-ergic, project into the cerebral cortex and thus may also p articipate in the modulation of its activity. We have performed a comp arative study of the intrinsic rhythmic properties of immunohistochemi cally and morphologically characterized choline acetyltransferase (ChA T)-positive and ChAT-negative cells of the nucleus basalis by means of intracellular recordings in guinea pig brain slices. Our results demo nstrate that relatively large, multipolar cholinergic and non-choliner gic neurons each display differential voltage-dependent properties tha t allow them to discharge rhythmically in spike bursts and spike clust ers, respectively, at low frequencies (<10 Hz). Cholinergic cells disp lay bursts of 2-4 action potentials (at similar to 200 Hz) riding on l ow-threshold spikes recurring at a low frequency (<5 Hz) when depolari zed from a membrane potential more negative than -55 mV and display lo w-frequency (<10-15 Hz) tonic firing when depolarized from a more posi tive level. In contrast, non-cholinergic cells fire in a unique mode, displaying non-adapting clusters of spikes interspersed with rhythmic subthreshold membrane-potential oscillations when depolarized from lev els less negative than -55 mV. The spike clusters repeat rhythmically at relatively low frequencies (2-10 Hz). The intracluster spiking freq uency is relatively high and coincides approximately with that of the intervening membrane-potential oscillations (similar to 20-70 Hz). The duster frequency of the non-cholinergic cells corresponds, in the sam e manner as the burst frequency of the cholinergic cells, to a delta ( 1-4 Hz) or theta (4-10 Hz) range of activity, whereas the intra-cluste r and tonic spike frequencies of the non-cholinergic cells correspond to high beta to gamma ranges of electroencephalographic activity (19-3 0 Hz and 30-60 Hz, respectively). We propose that the different modes of oscillatory firing by the cholinergic and non-cholinergic basal for ebrain cell populations could collectively contribute to the rhythmic modulation of slow and fast rhythms within the cerebral cortex.