title: Load-dependent dysfunction of the putamen during attentional processing in patients with clinically isolated syndrome suggestive of multiple sclerosis.
abstract: BACKGROUND
  Load-related functional magnetic resonance imaging (fMRI) abnormalities of brain activity during performance of attention tasks have been described in definite multiple sclerosis (MS). No data are available in clinically isolated syndrome (CIS) suggestive of MS.
  
  
  OBJECTIVE
  The objective of this research is to evaluate in CIS patients the fMRI pattern of brain activation during an attention task and to explore the effect of increasing task load demand on neurofunctional modifications.
  
  
  METHODS
  Twenty-seven untreated CIS patients and 32 age- and sex-matched healthy controls (HCs) underwent fMRI while performing the Variable Attentional Control (VAC) task, a cognitive paradigm requiring increasing levels of attentional control processing. Random-effects models were used for statistical analyses of fMRI data.
  
  
  RESULTS
  CIS patients had reduced accuracy and greater reaction time at the VAC task compared with HCs (p=0.007). On blood oxygenation level-dependent (BOLD)-fMRI, CIS patients had greater activity in the right parietal cortex (p=0.0004) compared with HCs. Furthermore, CIS patients had greater activity at the lower (p=0.05) and reduced activity at the greater (p=0.04) level of attentional control demand in the left putamen, compared with HCs.
  
  
  CONCLUSIONS
  This study demonstrates the failure of attentional control processing in CIS. The load-related fMRI dysfunction of the putamen supports the role of basal ganglia in the failure of attention observed at the earliest stage of MS.
authors: Department of Neuroscience and Sense Organs, University of Bari, Italy.
authors: C
authors: C
authors: Tortorella
authors: R
authors: R
authors: Romano
authors: V
authors: V
authors: Direnzo
authors: P
authors: P
authors: Taurisano
authors: S
authors: S
authors: Zoccolella
authors: P
authors: P
authors: Iaffaldano
authors: L
authors: L
authors: Fazio
authors: R
authors: R
authors: Viterbo
authors: T
authors: T
authors: Popolizio
authors: G
authors: G
authors: Blasi
authors: A
authors: A
authors: Bertolino
authors: M
authors: M
authors: Trojano
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003711:Demyelinating Diseases / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009103:Multiple Sclerosis / Q000503:physiopathology; D011699:Putamen / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology
keywords: Clinically isolated syndrome (CIS); attention; basal ganglia; cognition; fMRI