CACNA1C and Cognitive impairment: Therefore, the present results support the ‘calcium hypothesis of aging’ (Khachaturian, 1987; Landfield, 1987) in that the age-related increase in surface expression of L-type voltage-gated Ca2+ channels (Cav1.2 and Cav1.3) in hippocampal pyramidal neurons we demonstrate may play an important role in the cognitive deficits observed in normal aging subjects.