title: Default network connectivity is linked to memory status in multiple sclerosis.
abstract: Memory impairment affects 50% of multiple sclerosis (MS) patients. Altered resting-state functional connectivity (FC) has been observed in the default network (DN) of MS patients. No study to date has examined the association of DN FC to its behavioral concomitant, memory. The approach of the present study represents a methodological shift allowing straightforward interpretation of FC alterations in MS, as it presupposes specificity of a network to its paired cognitive function. We examined FC from fMRI collected during rest in the DN of 43 MS patients with and without memory-impairment. Memory-intact patients showed increased DN FC relative to memory-impaired patients. There were no regions of higher FC in memory-impaired patients. DN FC was positively correlated with memory function, such that higher FC was associated with better memory performance. Results were unchanged after controlling for cognitive efficiency, supporting specificity of the DN to memory and not cognitive status more generally. These findings support DN FC as a marker of memory function in MS patients that can be targeted by future treatment interventions. Pairing a functional network with its behavioral concomitant represents a straightforward method for interpreting FC alterations in patients with MS.
authors.affiliation: 1Columbia University Multiple Sclerosis Clinical Care and Research Center,Cognitive Neuroscience Division,Department of Neurology,Columbia University Medical Center,New York,New York.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Leavitt
authors.affiliation: 2SUNY Plattsburgh,Plattsburgh,New York.
authors.forename: Jessica
authors.initials: J
authors.lastname: Paxton
authors.affiliation: 3Kessler Foundation,Cognitive Neuroscience Laboratory,West Orange,New Jersey.
authors.forename: James F
authors.initials: JF
authors.lastname: Sumowski
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000473:pathology; D001931:Brain Mapping; D003072:Cognition Disorders / Q000209:etiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000209:etiology* / Q000473:pathology*; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications*; D009415:Nerve Net / Q000098:blood supply / Q000473:pathology; D009434:Neural Pathways / Q000098:blood supply* / Q000473:pathology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D012146:Rest
chemical_list: D010100:Oxygen