Fig. 6.

Early MD reduces the impact of a subsequent period of retinal inactivation on neurofilament labeling in the dLGN. Experimental timelines for each group are shown in A and D. Neurofilament labeling in the dLGN of an animal that received MD at postnatal day 30 for 6 weeks, then had their fellow eye inactivated for 10 days did not exhibit an obvious loss of immunolabeling in layers connected to the inactivated eye (arrows in A for the right and left dLGN). At higher magnification (B), roughly balanced labeling was observed throughout dLGN layers, and there was no obvious loss of neurofilament labeling within the layer serving the inactivated eye (IE) relative to the non-inactivated eye (NIE). This was confirmed by quantification of neurofilament-positive cell density, which showed a 5% difference between eye-specific layers that was not a significance difference (C). The group of animals that did not receive an early MD, but which did receive the same 10 days of monocular inactivation at the same age, expressed a clear loss of neurofilament labeling within layers serving the inactivated eye (arrows in D). This was obvious at high magnification where few neurofilament-positive neurons were observed in the inactivated-eye layers relative to layers serving the non-inactivated eye. Quantification of neurofilament-positive cell density revealed a 54% reduction within inactivated-eye layers (F), which was significantly different from fellow-eye layers. Scale bars = 1 mm (A and D) and 50 μm (B and E). Images in B and E were taken from dLGN A layers serving the non-inactivated eye (left image) and the inactivated eye (right image). Red and blue data points indicate measurements from A and A1 dLGN layers, respectively. Double asterisks indicate statistical significance (p < 0.05).