Koji IKEZOE, Hiroshi TAMURA, Fumitaka KIMURA, Ichiro FUJITA
Developmental change of noise correlation in rat primary somatosensory
Detectability and discriminability of sensory stimuli are limited in infant animals, and improve through sensory experiences as they grow. To explore neural mechanisms underlying the maturation process, we performed multiple single-unit recording in primary somatosensory cortex of anesthetized rats from postnatal day 5 (P5) to P31, and analyzed neural responses to identical single-whisker deflections. Noise correlation, which is correlation of trial-to-trial variability of responses between neurons, peaked at around P9 and gradually decreased towards P18. This period coincides with the time when exploring behavior of rats starts and develops. Pooling of responses across neurons with a low noise correlation in adult animals improved performance of a neuronal ensemble, whereas pooling effects were deteriorated for neurons with a high noise correlation in infant animals. The results suggest that high noise correlation is a limiting factor for psychophysical performance of infant animals.