The 'window' T-type calcium current in brain dynamics of different behavioural states

Abstract

All three forms of recombinant low voltage-activated T-type Ca2+ channels (Cav3.1, Cav3.2 and Cav3.3) exhibit a small, though clearly evident, window T-type Ca2+ current (ITwindow) which is also present in native channels from different neuronal types. In thalamocortical (TC) and nucleus reticularis thalami (NRT) neurones, and possibly in neocortical cells, an ITwindow-mediated bistability is the key cellular mechanism underlying the expression of the slow (< 1 Hz) sleep oscillation, one of the fundamental EEG rhythms of non-REM sleep. As the ITwindow-mediated bistability may also represent one of the cellular mechanisms underlying the expression of high frequency burst firing in awake conditions, ITwindow is of critical importance in neuronal population dynamics associated with different behavioural states. © The Physiological Society 2004.