Visual and motor cortex excitability: a transcranial magnetic stimulation study.
OBJECTIVE
Phosphene thresholds (PTs) to transcranial magnetic stimulation over the occipital cortex and motor thresholds (MTs) have been used increasingly as measures of the excitability of the visual and motor cortex. MT has been utilized as a guide to the excitability of other, non-motor cortical areas such as dorsolateral prefrontal cortex. The aims of this study were to compare the PTs to MTs; to assess their stability across sessions; and to investigate their relation to MTs.


METHODS
PTs and MTs were determined using focal transcranial magnetic stimulation over the visual and motor cortex.


RESULTS
PTs were shown to be significantly higher than MTs. Both PTs and MTs were stable across sessions. No correlation between PTs and MTs could be established.


CONCLUSIONS
Phosphene threshold is a stable parameter of the visual cortex excitability. MTs were not related to the excitability of non-motor cortical areas.
Boroojerdi
Babak
B
Neurologische Klinik, Universitätsklinikum, Pauwelsstrasse 30, 52074, Aachen, Germany. babak.boroojerdi@post.rwth-aachen.de
Meister
Ingo G
IG
Foltys
Henrik
H
Sparing
Roland
R
Cohen
Leonardo G
LG
Töpper
Rudolf
R
D000328:Adult; D004558:Electric Stimulation / Q000295:instrumentation; D004574:Electromagnetic Fields; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology / Q000528:radiation effects; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology* / Q000528:radiation effects*; D010719:Phosphenes / Q000502:physiology / Q000528:radiation effects; D012016:Reference Values; D012684:Sensory Thresholds / Q000502:physiology / Q000528:radiation effects; D050781:Transcranial Magnetic Stimulation; D014793:Visual Cortex / Q000502:physiology* / Q000528:radiation effects*