Bouton renewal patterns in rat hindlimb cortex after thoracic dorsal funicular lesions

Publisher Website
Google Scholar
Abstract
The transneuronal effect of bilateral, dorsal funicular lesions (T 12) on the frequency of boutons on cells in layer IV of hindlimb cortex was studies. Adult rats were utilized 1, 2, 3, 7, 14, 30, 45, 60, 90, or 120 days postoperative (DPO), and tissue was processed for the light microscopic visualization of silver-impregnated boutons (Rasmussen method). Bouton counts were taken on soma, or along 5- and 10-μm segments of proximal dendrite branching from soma. The soma diameter also was measured on those neurons chosen for bouton counts on the circumference of the soma. Statistically significant, increased afferentation on soma and proximal dendrite occurred during the first postlesion week relative to longer survival times; bouton counts on the proximal dendrite showed a trend (not statistically significant) toward increases above normal. These data mirror similar, consistent increases in bouton counts reported in thalamic ventroposterolateral nucleus of these same cases. At 14 DPO, bouton counts on the soma decreased below normal (P<0.005) and, except at 60 DPO, remained so through 120 DPO (P<0.025). Bouton counts on the proximal dendrite also decreased below normal at 14 DPO (P<0.005), thereafter exhibiting either periodic (along 5-7μm) or extended (along 10-7mu;m) periods in significant decreases from normal. Correlations in lesioned cases between the number of boutons on the soma and either bouton counts on proximal dendrite or soma diameter were positive and statistically significant (P<0.005 in all correlations). Possible anterograde (via the dorsal column-medial lemniscal system) and/or retrograde (via the corticospinal tract) transneuronal mediation of these effects in hindlimb cortex is discussed.

This publication has 39 references indexed in Scilit: