Reciprocal inhibitory connections produce desynchronizing phase lags during intrathalamic oscillations

In GABA A b 3 knockout mice (b~@~ 3 ), inhibitory synapses between thalamic reticular (RE) neurons are selectively impaired. Consequently, oscillations in thalamic slices from b~@~ 3 mice last longer and are more synchronized than those from wild-type mice (Huntsman et al., Science 283 (1999) 541). We used computational models to study mechanisms by which intra-RE inhibition abbreviates and desynchronizes intrathalamic oscillations. Intra-RE inhibition could produce the former e!ect by shunting recurrent excitation. Intra-RE inhibition could produce the latter e!ect by changing the duration, but not the timing, of RE cells' bursts. These results suggest mechanisms by which intra-RE inhibition prevents hypersynchrony characteristic of absence epilepsy. ( 2000 Elsevier Science B.V. All rights reserved.