Nous utilisons aussi des techniques de neuroanatomie et des méthodes quantitatives anatomiques.
Exemple d’identification de neurones pour quantifier les connections cortico-corticales:
Figure 7. Examples of cell body and terminal labeling. (From Dancause et al., JCN 2007)
A. Low magnification photomicrograph of retrograde labeling in the contralateral PMv of case 1934 following injection of BDA in the ipsilateral PMv DFL. Numerous labeled cell bodies and fibers can be observed. The gray square indicates the area magnified in B.
B. Cell body with multiple BDA-labeled dendrites (arrowheads). The long arrow points to the fiber that is magnified further (bottom). The many varicosities seen on this fiber (arrowheads) are typical of terminal bouton labeling in the present series of cases.
C. Low magnification of FB labeled cell bodies in the contralateral PMv of case 1892 following injection of FB in the contralateral PMv DFL. White square indicates the area magnified in D.
D. Magnified FB labeled cell bodies. Examples of protuberances considered to be dendrites are indicated by white arrowheads. Contrast and brightness of photographs were adjusted in Photoshop. Scale bar = 100µm.
Exemple de reconstruction des connections ipsilatérales de deux aires corticales (PMv et FR):
Figure 8. Comparison of the pattern of connections of PMv and FR distal forelimb representation in the ipsilateral hemisphere. (From Dancause et al., Cereb Cortex 2008)
A. Pattern of connections of PMv distal forelimb representation in the ipsilateral hemisphere. Reconstruction of the typical distribution of voxels with labeled terminals observed in flattened, tangential sections through the fronto-parietal cortex in a case with a BDA injection in the PMv DFL (case 1934; (Dancause et al., 2006b). This injection was of comparable size and depth as the FR injection in case 472 (Figure 3). As this animal received the largest BDA injection of any in that study, and displayed the most extensive and densest distribution of terminals, it provides a reasonable estimate of the limits of normal PMv connectivity. Each blue dot represents a voxel (100 X 100µm resolution; approximate depth 1500µm) in which at least two labeled varicocities (terminal boutons) were identified. ICMS-defined DFLs are outlined with red contours and histochemically-defined sensory areas (3b and area 1/2) in black contours. In particular, note the intense BDA labeling found in M1 and the sparse labeling found in FO. In addition, BDA labeling in AO is less intense and more caudal than what was found following BDA injection in FR.
B. Within case comparison of the pattern of connections of PMv and FR distal forelimb representation in the ipsilateral hemisphere. Distribution of labeled terminals following injection of BDA into FR DFL (orange dots; see Figure 3) and labeled cell bodies after injection of FB into PMv DFL (blue dots). One orange dot represents a voxel with labeled terminals and one blue dot represents a cell body. When both Fast-Blue and BDA were co-localized, green is used. Abbreviations as in Figure 3. Scale bar = 5mm.