Can GABA_A conductances explain the fast oscillation frequency of absence
seizures in rodents ?
Alain Destexhe
European Journal of Neuroscience 11: 2175-2181, 1999
Abstract:
Rodent models of absence epilepsy generate spike-and-wave oscillations at
relatively fast frequency (5-10 Hz) compared to humans (~3 Hz). Possible
mechanisms for these oscillations were investigated by computational models
that included the complex intrinsic firing properties of thalamic and cortical
neurons, as well as the multiple types of synaptic receptors mediating their
interactions. The model indicates that oscillations with spike-and-wave field
potentials can be generated by thalamo-cortical circuits. The frequency of
these oscillations critically depended on GABAergic conductances in thalamic
relay cells, ranging from 2-4 Hz for strong GABA_B conductances to 5-10 Hz
when GABA_A conductances were dominant. This model therefore suggests that
thalamo-cortical circuits can generate two types of spike-and-wave
oscillations, which frequency is determined by the receptor type mediating
inhibition in thalamic relay cells. Experiments are proposed to test this
mechanism.
See also the following related article:
Destexhe A. Spike-and-wave oscillations based on the
properties of GABA_B receptors. Journal of Neuroscience 18: 9099-9111,
1998.
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