title: Abnormal cortical synaptic plasticity in primary motor area in progressive supranuclear palsy.
abstract: No study has yet investigated whether cortical plasticity in primary motor area (M1) is abnormal in patients with progressive supranuclear palsy (PSP). We studied M1 plasticity in 15 PSP patients and 15 age-matched healthy subjects. We used intermittent theta-burst stimulation (iTBS) to investigate long-term potentiation (LTP) and continuous TBS (cTBS) to investigate long-term depression (LTD)-like cortical plasticity in M1. Ten patients underwent iTBS again 1 year later. We also investigated short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in M1 with paired-pulse transcranial magnetic stimulation, tested H reflex from upper limb flexor muscles before and after iTBS, and measured motor evoked potential (MEP) input-output (I/O) curves before and after iTBS. iTBS elicited a significantly larger MEP facilitation after iTBS in patients than in healthy subjects. Whereas in healthy subjects, cTBS inhibited MEP, in patients it significantly facilitated MEPs. In patients, SICI was reduced, whereas ICF was normal. H reflex size remained unchanged after iTBS. Patients had steeper MEP I/O slopes than healthy subjects at baseline and became even more steeper after iTBS only in patients. The iTBS-induced abnormal MEP facilitation in PSP persisted at 1-year follow-up. In conclusion, patients with PSP have abnormal M1 LTP/LTD-like plasticity. The enhanced LTP-like cortical synaptic plasticity parallels disease progression.
authors.affiliation: Department of Neurology and Psychiatry Sapienza, University of Rome, Viale dell'Università, 30, 00185 Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Conte
authors.forename: Daniele
authors.initials: D
authors.lastname: Belvisi
authors.forename: Matteo
authors.initials: M
authors.lastname: Bologna
authors.forename: Donatella
authors.initials: D
authors.lastname: Ottaviani
authors.forename: Giovanni
authors.initials: G
authors.lastname: Fabbrini
authors.forename: Carlo
authors.initials: C
authors.lastname: Colosimo
authors.forename: David R
authors.initials: DR
authors.lastname: Williams
authors.forename: Alfredo
authors.initials: A
authors.lastname: Berardelli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004185:Disability Evaluation; D018450:Disease Progression; D004558:Electric Stimulation / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006181:H-Reflex / Q000502:physiology; D006801:Humans; D017774:Long-Term Potentiation / Q000502:physiology; D036881:Long-Term Synaptic Depression / Q000502:physiology; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D013494:Supranuclear Palsy, Progressive / Q000473:pathology / Q000503:physiopathology*; D009435:Synaptic Transmission / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods