Aging reduces somatosensory responsiveness of caudate neurons in the awake cat

Neuronal activity was recorded in 7 awake cats (3 animals 11-15 years and 4 animals 1-3 years of age) to determine if the ability of caudate neurons to process facial somatosensory information was impaired in aged animals. Proportionately fewer neurons responded to somatosensory stimuli and facial receptive fields were larger in the aged cats. In addition, proportionately fewer caudate neurons responded to cortical activation, there were fewer excitatory responses and spontaneous firing decreasing in aged cats. These results provide additional evidence that excitability of caudate neurons is reduced in aged cats.