Studies On Changes And Brain Mechanisms Of Pattern Adaptation Of Visual Cortical Cells To Visual Stimulation During Aging

Pattern adaptation is one of the important properties in visual psychology and visual neurons'response to visual stimulation. A high contrast pattern selectively reduces the perceived contrast of a similar pattern in a subsequently viewed test stimulus. Such a perceptual phenomenon is termed"pattern adaptation". In this research, we used extracellular single-unit recording techniques to make preliminary studies on the Brain Mechanisms and Pattern adaptation of visual cortical cells to visual stimulation in aged cats.1.Aging leads to compromised intracortical inhibition. Whether aging affects the adaptation of cortical neurons to sensory stimulation remains unknown. In this study, adaptation of V1 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.2. Our results show that during adaptation, the mean firing rate (MF) of V1 neurons to visual stimulation is highly correlated with its burst firing frequency (BF) in both old and young adult cats. However, relative to young adult cats, the correlation of MF and BF of V1 neurons in old cats is significantly increased during adaptation to visual stimulation. This result further suggests that enhanced visual adaptation of visual cortical cells in the old brain may result from burst firing frequency changes that might be mediated by a decreased inhibition at cortical and subcortical levels.