Impaired working-memory after cerebellar infarcts paralleled by changes in BOLD signal of a cortico-cerebellar circuit.
A considerable body of evidence supports the notion that cerebellar lesions lead to neuropsychological deficits, including impairments in working-memory, executive tasks and verbal fluency. Studies employing functional magnetic resonance imaging (fMRI) and anatomical tracing in primates provide evidence for a cortico-cerebellar circuitry as the functional substrate of working-memory. The present fMRI study explores the activation pattern during an n-back working-memory task in patients with an isolated cerebellar infarct. To determine each patient's cognitive impairment, neuropsychological tests of working-memory and attention were carried out. We conducted fMRI in nine patients and nine healthy age-matched controls while they performed a 2-back task in a blocked-design. In both groups we found bilateral activations in a widespread cortico-cerebellar network, consisting of the ventrolateral prefrontal cortex (BA 44, 45), dorsolateral prefrontal cortex (BA 9, 46), parietal cortex (BA 7, 40), pre-supplementary motor area (BA 6) anterior cingulate (BA 32). Relative to healthy controls, patients with isolated cerebellar infarcts demonstrated significantly more pronounced BOLD-activations in the precuneus and the angular gyrus during the 2-back task. The significant increase in activation in the posterior parietal areas of the cerebellar patients could be attributed to a compensatory recruitment to maintain task performance. We conclude that cerebellar lesions affect remote cortical regions that are part of a putative cortico-cerebellar network.
Ziemus
B
B
Department of Neurology, University of Regensburg, Germany.
Baumann
O
O
Luerding
R
R
Schlosser
R
R
Schuierer
G
G
Bogdahn
U
U
Greenlee
M W
MW
D000328:Adult; D020520:Brain Infarction / Q000150:complications; D001931:Brain Mapping; D002526:Cerebellar Diseases / Q000150:complications; D002531:Cerebellum / Q000098:blood supply* / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000503:physiopathology*; D004292:Dominance, Cerebral; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009415:Nerve Net / Q000098:blood supply / Q000503:physiopathology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood
D010100:Oxygen