Figure 1

Schematic demonstrating anatomic structures investigated in the basal forebrain (A), mid-hypothalamus (tuberal level) (B), and caudal hypothalamus (mammillary level) (C) (see Materials and methods for detail). To the left of each schematic, grayscale renderings of TDP-43-stained sections of study patients are shown for comparison. In A, the continuity of rostral/chiasmatic hypothalamus and basal forebrain, as discussed in the text, is shown on both the histologic image (which also includes the optic chiasm) and on the schematic (POA). Abbreviations not defined in text: ac – anterior commissure, cc – crus cerebri, fmp – fasciculus mammillaris princeps (mammillary efferents), fx – fornix, GPe/i – external/internal segments of the globus pallidus, FPut – fundus of the putamen, ic – internal capsule, LV – lateral ventricle, mfb - medial forebrain bundle, mmt – mammillothalamic tract, mmtg – mammillotegmental tract, ot – optic tract, 3v – third ventricle.