早期鬍鬚剪除對成年大鼠行為、神經元結構及神經活動之 影響

Abstract

Early sensory experience plays essential roles in development of sensory systems. For example, early surgical manipulations of whiskers in rodents lead to altered neural activity and behaviors later in life. However, the surgical procedures damage the sensory pathway; it is impossible to examine the consequence if recovery of the sensory pathway is unfeasible. To address this issue, we performed a neonatal whisker trimming (WC0-3) paradigm, a non-invasive procedure, from the day of birth (P0) to postnatal day (P) 3, and examined the behavioral performances in their adult life. With fully regrown whiskers, the WC0-3 rats exhibited shorter maximal crossable distance than the controls in the gap-crossing task, suggesting the defect in their whisker-specific tactile function, although the barrel pattern in the somatosensory cortex was not significantly changed. The spiny stellate neurons in layer IV were found to be possessed with decreased complexity of dendritic arbor and spine density. After exploration in a novel environment, the expression of activity-dependent early immediate early gene, c-fos, was increased dramatically in the somatosensory cortex. However, in the WC0-3 rats, the number of c-fos positive cells was much less than that in the control rats, especially in the upper and lower cortical layers, indicating the fault in transducing sensory-related neural activity between cortical layers in the WC0-3 rats. With defect in the somatosensory system, the WC0-3 rats exhibited higher explorative activity in an open field. Our results demonstrated that early tactile deprivation disturbs the brain development and leaves long-lasting functional deficits in the nervous system.