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Dissociation of slow waves and fast oscillations above 200 Hz during GABA application in rat somatosensory cortex
Author(s) -
Staba Richard J.,
Bergmann Peter C.,
Barth Daniel S.
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.075325
Subject(s) - somatosensory system , neuroscience , neocortex , excitatory postsynaptic potential , chemistry , dissociation (chemistry) , sensory system , stimulus (psychology) , biophysics , biology , psychology , inhibitory postsynaptic potential , psychotherapist
Fast electrical oscillations (FOs; > 200 Hz), superimposed on vibrissa‐evoked slow potentials, may support rapid sensory integration in neocortex. Yet, while it is well established that the positive/negative (P1/N1) slow wave of the somatosensory evoked potential primarily reflects sequential activation of supragranular and infragranular pyramidal cells mediated chiefly via excitatory chemical synaptic pathways, little is known about the generation of FOs. In this study, laminar current source–density analysis and principal component analysis indicated that FOs are generated by two dipolar current sources situated in the supra‐ and infragranular layers, similar in laminar location to the two current dipoles associated with the slow wave. However, exogenous GABA application reversibly abolished the N1 slow wave, leaving the P1 intact, while the FO was unaffected by GABA. Furthermore, reductions in both supra‐ and infragranular cortical unit discharge during application of GABA suggests that FO generation is not dependent on the same intracortical synaptic circuits that are associated with the N1 slow wave. These data suggest a marked functional dissociation between neural mechanisms underlying the slow and fast components of the vibrissa‐evoked response.