Figure 1.

Orientation, location, and internal boundary of the marmoset claustrum. Panel (A) shows the lateral, oblique, and front views (left to right, respectively) of the marmoset claustrum complex in red, reconstructed from serial histological sections. The relative lissencephaly of the marmoset brain is evident, with the two major cortical sulci, the lateral sulcus (dark) and calcarine sulcus (white) visible in the lateral view. Note the significant change in the orientation of the claustrum complex axes from rostral to caudal, which can make comparison of e.g., medial or ventral regions difficult across the length of the structure. Panel (B) shows a representative myelin stained section from case CJ167. Adjacent structures, including the lateral nucleus of the amygdala, insular cortex, and putamen, are indicated, and the myelin-sparse dorsal subdivision of the dorsal endopiriform nucleus (DEnD) is highlighted in pink. Panel (C) shows the serial reconstruction of the claustrum complex from wireframe outlines of myelin sections in case CJ167 (performed using ImageJ software). The pink region within each section indicates the boundary of the DEnD region as identified in the myelin series. Jagged edges on the dorsal and ventral surface of the pink regions indicate interpolation artifacts from the slice registration. Inter-section interval is approximately 200 μm per slice. The wireframe reconstruction is oriented at approximately the same frontal oblique angle as the middle section of (A). The white asterisk indicates the position of the section shown in (B). Note that an enlarged and parcellated figure containing the tissue section in (B) appears as a preliminary data figure in Smith et al. (2019; Figure 9).