|Notes: RM312 MI injection|
The injection of CTB is centered in the middle of cytoarchitectonic area 4 at about the middle of its medio-lateral extent and immediately posterior to the arcuate sulcus. The maximal extent of the injection can be seen on sections 156-166. Anteriorly, there may be some encroachment on area 6 in the posterior bank of the arcuate sulcus.
Going anteriorly from the injection (diminishing section numbers from section 145), cellular labeling in area 4 itself is quite localized. There are distinct patches of coincident anterograde and retrograde labeling in area 6 below and posterior to the arcuate sulcus and in medial area 6 above the cingulate sulcus and adjacent to the area 4 border. There are a few scattered labeled cells in the cingulate gyrus (area 24).
Over the course of the injection and continuing posteriorly (sections 139-189), there is a distinct patch of retrograde and anterograde labeling along the fundus of the cingulate sulcus in what is probably a further division of area 6.
Posterior to the injection (increasing section numbers from section 170), there are two patches of anterograde and retrograde label in area 4, with a few scattered labeled cells elsewhere in area 4, their numbers declining posteriorly (sections 205-218). Retrograde labeling of cells in the upper layers of areas 1 and especially 2 can be seen in sections 220-250. There are also patches of labeled cells in the medial bank of the intraparietal sulcus (area 2 or 5) and in the upper bank of the lateral sulcus (area SII). Further posteriorly (sections 259-269) there is a distinct patch of coincident retrograde and anterograde labeling in area 7 in the medial bank of the intraparietal sulcus. This may reflect involvement of part of area 6 in the injection.
Elsewhere, there is retrograde labeling of cells throughout the greater part of the claustrum (sections 170-228), a patch of anterograde label in the putamen in sections 180-201, and in the thalamus patches of retrograde and anterograde labeling can be seen in the VLp nucleus in sections 222-245 and in the CL nucleus in sections 240-255.