Research Reports - Changes in cortical plasticity in relation to a history of concussion during adolescence
Front Hum Neurosci. 2017 Jan 17;11:5. doi: 10.3389/fnhum.2017.00005. eCollection
Meehan SK(1), Mirdamadi JL(1), Martini DN(1), Broglio SP(1).
Adolescence and early adulthood is a critical period for neurophysiological
development potentially characterized by an increased susceptibility to the
long-term effects of traumatic brain injury. The current study investigated
differences in motor cortical physiology and neuroplastic potential across a
cohort of young adults with adolescent concussion history and those without.
Transcranial magnetic stimulation (TMS) was used to assess motor evoked potential
(MEP) amplitude, short-interval cortical inhibition (SICI) and intracortical
facilitation (ICF) before and after intermittent theta burst stimulation (iTBS).
Pre-iTBS, MEP amplitude, but not SICI or ICF, was greater in the concussion
history group. Post-iTBS, the expected increase in MEP amplitude and ICF was
tempered in the concussion history group. Change in SICI was variable within the
concussion history group. Post hoc assessment revealed that SICI was
significantly lower in individuals whose concussion was not diagnosed at the time
of injury compared to both those without a concussion history or whose concussion
was medically diagnosed. Concussive impacts during adolescence appear to result
in a persistent reduction of the ability to modulate facilitatory motor networks.
Failure to report/identify concussive impacts close to injury during adolescence
also appears to produce persistent change in inhibitory networks. These findings
highlight the potential long-term impact of adolescent concussion upon motor