Stable motor cortex excitability in red and green lighting conditions.
Illumination science has long established effects of coloured light on emotional state, cognitive performance, plus tactile, gustatory and olfactory perception. To explore the neurobiological mechanisms underlying these crossmodal phenomena, cortical excitability was addressed by single and paired-pulse transcranial magnetic stimulation (TMS) in 23 men with normal colour vision, and in 10 subjects with red-green blindness. Using a sequential challenge, excitability measures were recorded at baseline and during exposure to either red or green light. Dichromacy did not predict any of the electrophysiological parameters under study regardless of the spectral paradigm. In both dichromats and trichromats, red and green illumination did not induce any significant effects on resting motor threshold, short intracortical inhibition, intracortical facilitation and cortical silent periods. Our results suggest that motor cortex excitability as assessed by TMS is not sensitive to the modulatory effects of context-independent red and green light.
Langguth
Berthold
B
Department of Psychiatry, University of Regensburg, Universitaetsstrasse 84, 93053 Regensburg, Germany. Berthold.Langguth@medbo.de
Eichhammer
Peter
P
Pickert
Karin
K
Frank
Ulrike
U
Perna
Martin
M
Landgrebe
Michael
M
Frick
Ulrich
U
Hajak
Goeran
G
Sand
Philipp
P
D000328:Adult; D000704:Analysis of Variance; D055592:Biophysical Phenomena; D003118:Color Perception / Q000502:physiology*; D055253:Color Vision / Q000502:physiology*; D003265:Contingent Negative Variation / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult