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Can GABAA conductances explain the fast oscillation frequency of absence seizures in rodents?Alain DestexheEuropean Journal of Neuroscience 11: 2175-2181, 1999 html copy Copy of the full paper (PDF)AbstractRodent 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. |