CACNA1H and juvenile absence epilepsy: Thus, the use of TTA-P2 to provide a fast block of T-channel function without compensatory activities shows that T-channels of ventrobasal thalamocortical neurons (i.e. Cav3.1) are not essential for spontaneous absence seizures in GAERS rats whereas those of the CIN (i.e. Cav3.1, Cav3.2 and Cav3.3) and NRT (i.e Cav3.2 and Cav3.3) are (Fig. 5).