title: Memory in multiple sclerosis is linked to glutamate concentration in grey matter regions.
abstract: OBJECTIVE
  Glutamate is the principal excitatory neurotransmitter and is involved in normal brain function. Cognitive impairment is common in multiple sclerosis (MS), and understanding its mechanisms is crucial for developing effective treatments. We used structural and metabolic brain imaging to test two hypotheses: (i) glutamate levels in grey matter regions are abnormal in MS, and (ii) patients show a relationship between glutamate concentration and memory performance.
  
  
  METHODS
  Eighteen patients with relapsing-remitting MS and 17 healthy controls were cognitively assessed and underwent (1)H-magnetic resonance spectroscopy at 3 T to assess glutamate levels in the hippocampus, thalamus, cingulate and parietal cortices. Regression models investigated the association between glutamate concentration and memory performance independently of magnetisation transfer ratio values and grey matter lesions withint he same regions, and whole-brain grey matter volume.
  
  
  RESULTS
  Patients had worse visual and verbal memory than controls. A positive relationship between glutamate levels in the hippocampal, thalamic and cingulate regions and visuospatial memory was detected in patients, but not in healthy controls.
  
  
  CONCLUSIONS
  The relationship between memory and glutamate concentration, which is unique to MS patients, suggests the reliance of memory on glutamatergic systems in MS.
authors.affiliation: Department of Neuroinflammation, NMR Research Unit, UCL Institute of Neurology, London, UK Cognitive Neuroscience, Department of Psychology, Cardiff University, Cardiff, UK.
authors.forename: Nils
authors.initials: N
authors.lastname: Muhlert
authors.affiliation: Department of Brain Repair and Rehabilitation, NMR Research Unit, UCL Institute of Neurology, London, UK Department of Neurology, University of Padova, Padova, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Atzori
authors.affiliation: Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK.
authors.forename: Enrico
authors.initials: E
authors.lastname: De Vita
authors.affiliation: Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, UK.
authors.forename: David L
authors.initials: DL
authors.lastname: Thomas
authors.affiliation: Department of Neuroinflammation, NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Samson
authors.affiliation: Department of Neuroinflammation, NMR Research Unit, UCL Institute of Neurology, London, UK.
authors.forename: Claudia A M
authors.initials: CA
authors.lastname: Wheeler-Kingshott
authors.affiliation: Department of Anatomy and Neuroscience, Section of Clinical Neuroscience, VU University Medical Center, VUmc MS Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jeroen J G
authors.initials: JJ
authors.lastname: Geurts
authors.affiliation: Department of Neuroinflammation, NMR Research Unit, UCL Institute of Neurology, London, UK National Institute for Health and Research (NIHR) University College London Hospital (UCLH) Biomedical Research Centre, London, UK.
authors.forename: David H
authors.initials: DH
authors.lastname: Miller
authors.affiliation: Department of Brain Repair and Rehabilitation, NMR Research Unit, UCL Institute of Neurology, London, UK National Institute for Health and Research (NIHR) University College London Hospital (UCLH) Biomedical Research Centre, London, UK.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Thompson
authors.affiliation: Department of Brain Repair and Rehabilitation, NMR Research Unit, UCL Institute of Neurology, London, UK National Institute for Health and Research (NIHR) University College London Hospital (UCLH) Biomedical Research Centre, London, UK.
authors.forename: Olga
authors.initials: O
authors.lastname: Ciccarelli
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects / Q000627:therapeutic use; D000328:Adult; D000367:Age Factors; D001923:Brain Chemistry / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000378:metabolism* / Q000523:psychology*; D059906:Neuroimaging; D009483:Neuropsychological Tests
chemical_list: D000305:Adrenal Cortex Hormones; D018698:Glutamic Acid