173 Axonal Loss in Narcolepsy Type 1 Axonal density and orientation In narcolepsy type 1 compared to control donors (Table 3, Figure 3), significantly lower axon counts were found in the midbrain (-27.6% for the reticular formation and -15.1% for the pyramidal tract), corpus callosum (-16.6%) and anterior cingulate gyrus (-18.7%) in the Bielschowsky silver staining. Axon counts in the vermis were not significantly different between groups. Investigation of axonal orientation (the ratio between axon counts in and perpendicular to the main fibre direction) in the proximal corpus callosum, anterior cingulate gyrus and vermis revealed no significant between group differences. Statistical comparison between the number of remaining hypocretin cells and axon counts in the ROIs in narcolepsy type 1, revealed no significant correlations between both measures (Appendix A, Supplementary Table 1). Absolute axonal density measures of the narcolepsy type 1 with chronic opiate usage was generally comparable to other narcolepsy type 1 donors (Appendix A, Supplementary Table 1). 6
RkJQdWJsaXNoZXIy MjY0ODMw