In addition to these motor-based relations with the condition of the cerebellum and pons, other analyses have reported correlations between frontally-based cognitive impairment that can be related to compromised cerebellar or pontine structures and even of the white matter connecting the various nodes of the circuitry. Indeed, the volumes of selective regions of the cerebellum have been shown to be better predictors than frontal lobe volumes of executive and visuospatial deficits in alcoholics (Sullivan, 2003). Also in alcoholics, the volume of the pons and a white matter region in the midbrain common to both afferent corticocerebellar and efferent cerebellocortical fibers correlated with performance on neuropsychological tests including fluency, letter-number sequencing, trail-making B, Stroop interference, and the Wisconsin Card Sorting test (Chanraud et al., 2007). The number of fibers per volume coursing between the midbrain and pons correlated with performance on Part B of the Trail Making Test, which assesses visual search, working memory, and cognitive flexibility (Chanraud et al., 2009). Alcoholics clinically asymptomatic for pontine signs of CPM reveal significant correlations between poorer verbal and nonverbal fluency production (tests long
