Experimental Cohort:
Inclusion Criteria:
* age 10-15 years at enrollment
* enrolled after 6 weeks of mTBI injury
* exhibiting post-concussive symptoms (e.g., difficulty planning, sequencing, and executing a motor action)
* Sustained an mTBI or concussion within the past 12 months
* Parent and child proficient in English
Healthy Controls Cohort:
Inclusion Criteria:
* 10 to 15 years old
* no concussion history
* Parent and child proficient in English
Experimental Cohort:
Exclusion Criteria:
* loss of consciousness \> 30 minutes
* post-traumatic amnesia \> 24 hours
* intracranial findings on clinical imaging
* history of developmental delay
* history of learning disability or ADHD
* Sustained a lower limb or upper limb injury that has not healed
* History of Seizures
* Noticeable skin lesions/burns or any other severe skin problems at the site of the electrodes before the start of the stimulation.
* Parent/guardian report metal implants anywhere in the head/ncek/body on the MRI screening form (see attached).
* Parent/guardian report shrapnel/bullets in the body on the MRI screening form.
* Parent/guardian report any electronic implant such as a cardiac pacemaker, cochlear implant, ventricular shunt, cardiac defibrillator, aneurysm clips, pacing wires, any implant held in place with a magnet, heart valve, or deep brain stimulator on the MRI screening form.
* Parent/guardian report a craniotomy or any other surgery in the past 6 weeks on the MRI screening form.
* Parent/guardian report being claustrophobic on the MRI screening form.
* Parent/guardian report and provide orbit x-ray after the eye injury involving a metal that the subject is cleared as indicated on the MRI screening form.
* Pregnant females as reported by parent/guardian on the pre-consent screening form. Pubertal/post-pubertal female participants14 and above will be provided a separate post-consent screening form at each MRI visit to ensure the female reports accurately without fear.
Healthy Controls Cohort:
Exclusion Criteria:
* diagnosed with developmental delay
* sustained a lower limb or upper limb injury that has not healed
* history of Learning Disability and/or ADHD
* Parent/guardian report metal implants anywhere in the head/ncek/body on the MRI screening form (see attached).
* Parent/guardian report shrapnel/bullets in the body on the MRI screening form.
* Parent/guardian report any electronic implant such as a cardiac pacemaker, cochlear implant, ventricular shunt, cardiac defibrillator, aneurysm clips, pacing wires, any implant held in place with a magnet, heart valve, or deep brain stimulator on the MRI screening form.
* Parent/guardian report a craniotomy or any other surgery in the past 6 weeks on the MRI screening form.
* Parent/guardian report being claustrophobic on the MRI screening form.
* Parent/guardian report and provide orbit x-ray after the eye injury involving a metal that the subject is cleared as indicated on the MRI screening form.
* Pregnant females as reported by parent/guardian on the pre-consent screening form. Post-pubertal females 14 and above will be provided a separate post-consent screening form at each MRI visit to ensure the female reports accurately without fear.
