Minimal alterations in T-type calcium channel gating markedly modify physiological firing dynamics.
Résumé
Non-technical summary Voltage-dependant calcium channels constitute a heterogeneous group playing ubiquitous roles in excitable cells. Among them the low-voltage activated T-type channels generate a family of currents that differ in their biophysical properties reflecting structural or neuromodulatory diversity. These T-type calcium channels are highly expressed in neurons located in the thalamus, a brain structure considered as the gateway to the cortex. Thalamic T-type calcium channels are critically involved in oscillatory neuronal activities associated with sleep or epilepsy and may contribute to sensory processing. Using injections of computer-simulated T-type conductances (a real time mimicry of ionic currents) in biological thalamic neurons, we dissect how the diversity in T-type currents impact on the output of thalamic neurons. We show that very subtle modifications in the properties of the T current that were overlooked so far affect drastically the physiological output of the thalamic neurons and therefore condition the dynamics of thalamo-cortical information integration.