title: Assessing low-frequency repetitive transcranial magnetic stimulation with functional magnetic resonance imaging: a case series.
abstract: OBJECTIVE
  This case series assesses the effects of five consecutive days of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) with and without a 6-Hz primer. Although this paper studies able-bodied individuals, similar rTMS protocols are used to facilitate motor recovery in patients with hemiplegia following stroke. However, the cortical mechanisms associated with repeated daily doses of rTMS are not completely understood.
  
  
  METHODS
  Four right-handed healthy volunteers (two men, aged 20-50 years) participated in a double-blind case series of primed and unprimed rTMS. Functional magnetic resonance imaging was used to compare task-related haemodynamics during a simple motor task and resting-state cortical connectivity. Understanding the mechanisms of repeated rTMS sessions may serve as a precursor to development of rTMS paradigms involving motor cortex stimulation in patients with a range of neurologic dysfunction.
  
  
  RESULTS
  Following five consecutive days of rTMS, all subjects had reduced task-related haemodynamics. Resting-state brain connectivity between motor regions was reduced only after primed rTMS.
  
  
  CONCLUSIONS
  This is the first study to indicate that resting-state brain connectivity can distinguish the effect of primed and unprimed rTMS to a greater extent than task-related haemodynamics. Furthermore, priming may inhibit the connectivity between the area of the cortex underlying the rTMS site and remote brain regions.
  
  
  CONCLUSIONS
  These findings benefit rTMS rehabilitation studies by examining haemodynamics on repeated days of stimulation and incorporating resting-state brain connectivity analysis to further understand underlying neural mechanisms. Furthermore, this work encourages the utilization of resting connectivity in future rTMS studies.
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA; Siemens Healthcare, Chicago, IL, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Glielmi
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Butler
authors.forename: Dmitriy M
authors.initials: DM
authors.lastname: Niyazov
authors.forename: Warren G
authors.initials: WG
authors.lastname: Darling
authors.forename: Charles M
authors.initials: CM
authors.lastname: Epstein
authors.forename: Jay L
authors.initials: JL
authors.lastname: Alberts
authors.forename: Xiaoping P
authors.initials: XP
authors.lastname: Hu
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D010100:Oxygen / Q000097:blood; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
chemical_list: D010100:Oxygen