LORETA indicates frequency-specific suppressions of current sources within the cerebrums of blindfolded subjects from patterns of blue light flashes applied over the skull.
An array of eight cloistered (completely covered) 470-nm LEDs was attached to the right caudal scalp of subjects while each sat blindfolded within a darkened chamber. The LEDs were activated by a computer-generated complex (frequency-modulated) temporal pattern that, when applied as weak magnetic fields, has elicited sensed presences and changes in LORETA (low-resolution electromagnetic tomography) configurations. Serial 5-min on to 5-min off presentations of the blue light (10,000lx) resulted in suppression of gamma activity within the right cuneus (including the extrastriate area), beta activity within the left angular and right superior temporal regions, and alpha power within the right parahippocampal region. The effect required about 5min to emerge followed by a transient asymptote for about 15 to 20min when diminished current source density was evident even during no light conditions. Subjective experiences, as measured by our standard exit questionnaire, reflected sensations similar to those reported when the pattern was presented as a weak magnetic field. Given previous evidence that photon flux density of this magnitude can penetrate the skull, these results suggest that properly configured LEDs that generate physiologically patterned light sequences might be employed as noninvasive methods to explore the dynamic characteristics of cerebral activity in epileptic and nonepileptic brains.
Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Biomolecular Sciences Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
Lukasz M
LM
Karbowski
Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Human Studies Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
Kevin S
KS
Saroka
Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Biomolecular Sciences Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
Nirosha J
NJ
Murugan
Behavioural Neuroscience Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Human Studies Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada; Biomolecular Sciences Program, Laurentian University, Sudbury, Ontario P3E 2C6, Canada. Electronic address: mpersinger@laurentian.ca.
Michael A
MA
Persinger
D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D000704:Analysis of Variance; D001611:Beta Rhythm / Q000502:physiology*; D004574:Electromagnetic Fields; D065818:Gamma Rhythm / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D012886:Skull; D013702:Temporal Lobe / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods*
Blue light; Bokkon photon field; Gamma activity; LORETA; Light-emitting diodes; Parahippocampal region; Sensed presence; Temporal lobes