title: Functional diffusion-weighted magnetic resonance spectroscopy of the human primary visual cortex at 7 T.
abstract: OBJECTIVE
  Microstructural and metabolic changes directly related to neuronal activation have been investigated using functional diffusion-weighted spectroscopy.
  
  
  METHODS
  The volume of interest was positioned in the primary visual cortex. A time series of alternating diffusion- and non-diffusion-weighted (1)H spectra was acquired at 7 T employing stimulated echo acquisition mode sequence and a long diffusion time (Δ = 245 ms). Time-resolved series of metabolite apparent diffusion coefficient values were derived.
  
  
  RESULTS
  Significant increases in apparent diffusion coefficient of 3.3 ± 1.4% (p = 0.05) and 3.9 ± 0.9% (p = 0.002) for total n-acetyl aspartate and total creatine, respectively, and 8.1 ± 2.5% (p = 0.03) for total choline were observed in response to visual stimulation.
  
  
  CONCLUSIONS
  The increase in apparent diffusion coefficient for these metabolites is a potential indication for microstructural changes in neurons during neural activation and/or for an increase in the energy-dependent cytoplasmic streaming associated with enhanced metabolism during visual stimulation.
authors.affiliation: C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Francesca
authors.initials: F
authors.lastname: Branzoli
authors.forename: Aranee
authors.initials: A
authors.lastname: Techawiboonwong
authors.forename: Hermien
authors.initials: H
authors.lastname: Kan
authors.forename: Andrew
authors.initials: A
authors.lastname: Webb
authors.forename: Itamar
authors.initials: I
authors.lastname: Ronen
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002794:Choline / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline