Enhanced adaptation of visual cortical cells to visual stimulation in aged cats.

Aging leads to compromised intracortical inhibition. Whether aging affects the adaptation of cortical neurons to sensory stimulation remains unknown. In this study, adaptation of V(1) neurons to visual stimuli was compared between young adult and aged cats using in vivo extracellular single-unit recording techniques. Our results indicated that neurons in aged cats exhibited significantly stronger adaptation to visual stimuli than did neurons in young adult cats. The enhanced adaptation of visual cortical cells to visual stimulation in the aging brain, which is of great significance to the energy savings in neuronal activity of senescent individuals, could be underlied by a simultaneous change of somatic afterhyperpolarization and synaptic depression mediated by an extensive age-related GABAergic inhibition reduction at cortical and subcortical level.