Modification of Peak Plasticity Induced by Brief Dark Exposure

Figure 3

Examination of the magnitude of neurofilament loss in the dLGN from animals that were either monocularly deprived for 7 days at the peak of the critical period or else received 10 days of dark exposure before the same length of MD. Monocular deprivation alone produced a substantial reduction in the amount of neurofilament labeling within deprived-eye dLGN layers (a1). At high magnification, the loss of labeling was evident as a reduced number of immunopositive neurons, as well as a reduction in labeling intensity (a2) in deprived-eye (DE) relative to non-deprived-eye (NDE) layers. When the same MD was preceded by 10 days of darkness, a similar reduction in neurofilament within deprived-eye layers was observed at low (b1) as well as at high magnification (b2). Stereological quantification of the density of neurofilament-positive neurons revealed that MD-only (a3) and MD preceded by dark exposure (b3) produced a similar deprivation effect, each with a significant reduction in deprived layers. Arrows in (a1) and (b1) indicate the deprived-eye layer. Asterisks indicate statistical significance at . (1) and 50 μm (2).