A New Visual Scale to Assess White Matter Hyperintensities Within Cholinergic Pathways

Neural networks of the human cerebral cortex responsible for attention, memory, and emotions are modulated by cholinergic input from the 4 overlapping Ch1–Ch4 cell groups of the basal forebrain.1,2 Cholinergic neurons of the medial septal nucleus (Ch1 cell group) and the vertical limb nucleus of the diagonal band (Ch2) provide the major cholinergic input to the hippocampus. Cholinergic neurons of the horizontal limb nucleus of the diagonal band (Ch3) provide the major cholinergic input of the olfactory bulb, and cholinergic neurons of the nucleus basalis of Meynert (nbM-Ch4) provide the principal cholinergic input of the remaining cerebral cortex and amygdala. Trajectories of these cholinergic fibers in white matter have been described recently in humans.2Cholinergic system damage leads to cognitive decline,3 thus, it is expected that the magnitude and extent of the damage will correlate with the degree of decline. White matter hyperintensities (WMHs) are encountered frequently on magnetic resonance (MR) scans of normal elderly people as well as in patients with various types of dementia. These hyperintensities are presumably related to small infarcts and lacunes caused by cerebrovascular …