Fig. 1.
Senescent neurophysiology. Senescent neurophysiology in the CA1 region of the hippocampus includes an increase in the afterhyperpolarization (AHP), a decrease in the NMDA receptor component of synaptic transmission, and a shift in synaptic plasticity. (A) A burst of action potentials (APs) initiates Ca2+-dependent activation of K+ channels resulting in a subsequent AHP. The amplitude of the AHP increases during aging. (B) Illustration of isolated NMDA receptor synaptic transmission. The NMDA receptor component of synaptic transmission decreases during aging. (C) The larger AHP and decrease in NMDA receptor function underlie a shift in synaptic plasticity, decreasing the probability or amplitude of LTP and increasing susceptibility for LTD.