Repetitive TMS in right sensorimotor areas affects the selection and completion of contralateral movements.
Although the existence of directional motor deficits (DMD) associated with movement planning and/or execution seems to be widely recognized, neglect and single cell studies examining their neuroanatomical foundation have produced contradictory and inconclusive findings. The present study assessed the occurrence of DMD following the application of repetitive transcranial magnetic stimulation (rTMS) over two regions, as commonly reported in the neglect literature, namely the right middle frontal gyrus (rMFG) and the right angular gyrus (rAG). Fourteen healthy subjects underwent rTMS while performing an auditory choice task, involving pointing toward two laterally located targets, under internally (i.e., pointing side freely selected) and externally guided conditions (i.e., pointing side guided by spatial auditory cues). In order to examine whether subjects compensated for induced deficits with the help of vision, visual feedback was occluded at movement onset in half of the trials. rTMS applied to the rAG significantly increased reaction times (RTs) for leftward internally-guided movements. In contrast, rTMS applied to the rMFG reduced the likelihood to complete leftward internally-guided movements under blindfolded conditions. These effects suggest that DMD might involve cognitive processes contributing to the different stages of motor control, such as movement selection and goal maintenance.
Chair of Human Movement Science, Faculty for Sports and Health Sciences, Technical University of Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig Maximilians University of Munich, Germany. Electronic address: maria.herrera@tum.de.
Maria
M
Gutierrez-Herrera
Department of Neurology, Bogenhausen City Hospital of the Technical University of Munich, Germany.
Styrmir
S
Saevarsson
Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Germany.
Thomas
T
Huber
Chair of Human Movement Science, Faculty for Sports and Health Sciences, Technical University of Munich, Germany.
Joachim
J
Hermsdörfer
Chair of Human Movement Science, Faculty for Sports and Health Sciences, Technical University of Munich, Germany.
Waltraud
W
Stadler
D000328:Adult; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D066191:Sensorimotor Cortex / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult
Directional motor deficits; Repetitive TMS; Right angular gyrus; Right middle frontal gyrus; Unilateral neglect