Cerebellar-parietal dysfunctions in multiple sclerosis patients with cerebellar signs.
Consistent findings have shown that the cerebellum is critically implicated in a broad range of cognitive processes including executive functions. Of note, cerebellar symptoms and a number of cognitive deficits have been widely reported in patients with multiple sclerosis (MS). This study investigated for the first time the role of cerebellar symptoms in modulating the neural networks associated with a cognitive task broadly used in MS patients (Paced Visual Serial Addition Test (PVSAT)). Twelve relapsing-remitting (RR) MS patients with prevalent cerebellar signs and symptoms (RR-MSc), 15 RR-MS patients without cerebellar manifestation (RR-MSnc) and 16 matched-healthy controls were examined during functional magnetic resonance imaging (fMRI). We tested whether the RR-MSc patients displayed abnormal activations within "cognitive" cerebellar regions and other areas typically engaged in working memory and tightly connected with the cerebellum. Despite similar behavioral performances during fMRI, RR-MSc patients displayed, relatively to both RR-MSnc patients and controls, significantly greater responses in the left cerebellar Crus I/Lobule VI. RR-MSc patients also displayed reduced functional connectivity between the left cerebellar Crus I and the right superior parietal lobule (FWE<.05). These results demonstrated that the presence of the cerebellar signs drastically impacts on the neurofunctional networks underlying working memory in MS. The altered communication between the cerebellum and a cortical area implicated in short-term buffering and storage of relevant information, offer new insights into the pathophysiological mechanisms of cognition in MS.
Unità di Ricerca Neuroimmagini, Istituto di Scienze Neurologiche-Consiglio Nazionale delle Ricerche, 88100 Catanzaro, Italy. a.cerasa@unicz.it
Antonio
A
Cerasa
Luca
L
Passamonti
Paola
P
Valentino
Rita
R
Nisticò
Domenico
D
Pirritano
Maria Cecilia
MC
Gioia
Carmelina
C
Chiriaco
Graziella
G
Mangone
Paolo
P
Perrotta
Aldo
A
Quattrone
D000328:Adult; D002526:Cerebellar Diseases / Q000209:etiology / Q000503:physiopathology*; D002531:Cerebellum / Q000503:physiopathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000503:physiopathology* / Q000523:psychology; D009434:Neural Pathways / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000503:physiopathology*