Publication
Title
Transient rhythmic network activity in the somatosensory cortex evoked by distributed input **in vitro**
Author
Abstract
The initiation and maintenance of physiological and pathophysiological oscillatory activity depends on the synaptic interactions within neuronal networks. We studied the mechanisms underlying evoked transient network oscillation in acute slices of the adolescent rat somatosensory cortex and modeled its underpinning mechanisms. Oscillations were evoked by brief spatially distributed noisy extracellular stimulation, delivered via bipolar electrodes. Evoked transient network oscillation was detected with multi-neuron patch-clamp recordings under different pharmacological conditions. The observed oscillations are in the frequency range of 25 Hz and consist of 412 mV large, 40150 ms wide compound synaptic events with rare overlying action potentials. This evoked transient network oscillation is only weakly expressed in the somatosensory cortex and requires increased [K+]o of 6.25 mM and decreased [Ca2+]o of 1.5 mM and [Mg2+]o of 0.5 mM. A peak in the cross-correlation among membrane potential in layers II/III, IV and V neurons reflects the underlying network-driven basis of the evoked transient network oscillation. The initiation of the evoked transient network oscillation is accompanied by an increased [K+]o and can be prevented by the K+ channel blocker quinidine. In addition, a shift of the chloride reversal potential takes place during stimulation, resulting in a depolarizing type A GABA (GABAA) receptor response. Blockade of α-amino-3-hydroxy-5-methyl-4-isoxazole-proprionate (AMPA), N-methyl-d-aspartate (NMDA), or GABAA receptors as well as gap junctions prevents evoked transient network oscillation while a reduction of AMPA or GABAA receptor desensitization increases its duration and amplitude. The apparent reversal potential of −27 mV of the evoked transient network oscillation, its pharmacological profile, as well as the modeling results suggest a mixed contribution of glutamatergic, excitatory GABAergic, and gap junctional conductances in initiation and maintenance of this oscillatory activity. With these properties, evoked transient network oscillation resembles epileptic afterdischarges more than any other form of physiological or pathophysiological neocortical oscillatory activity.
Language
English
Source (journal)
Neuroscience / International Brain Research Organization. - Oxford
Publication
Oxford : 2006
ISSN
0306-4522
Volume/pages
140:4(2006), p. 1401-1413
ISI
000238987100028
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 10.02.2011
Last edited 03.11.2017