Isometric agonist and antagonist muscle activation interacts differently with 140-Hz transcranial alternating current stimulation aftereffects at different intensities
Y. Shorafa, Islam Halawa, M. Hewitt, Michael A. Nitsche, Andrea Antal, Walter Paulus
Abstract
Stimulation intensity and activation of center versus surround muscles affect cortical excitability alterations generated by 140-Hz tACS. At rest, excitatory aftereffects were induced by tACS with 1 mA, but not 2 mA stimulation intensity. With agonistic muscle activation, excitability first decreases, and then increases with 2 mA. For antagonist activation, the MEP amplitude reduction observed in the sham condition is counteracted upon by 1 and 2 mA tACS. This reflects the relation of LTP-like aftereffects to Ca 2+ concentration alterations.
Topics & Concepts
Transcranial alternating current stimulationAgonistStimulationAntagonistChemistryNeuroscienceTranscranial magnetic stimulationLong-term potentiationMotor cortexAgonist-antagonistPsychologyReceptorBiochemistryTranscranial Magnetic Stimulation StudiesMuscle activation and electromyography studiesVestibular and auditory disorders