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Updated: Jun 15, 2026
A Novel Approach for Documenting Phosphenes Induced by Transcranial Magnetic Stimulation
Published on: April 1, 2010
Retinal origin of phosphenes to transcranial alternating current stimulation
Dennis J L G Schutter1, Ruud Hortensius
1Experimental Psychology, Helmholtz Research Institute, Utrecht University, Heidelberglaan 2, 3584CS Utrecht, The Netherlands. d.schutter@uu.nl
Objective:
To examine possible retinal contributions to cortically induced phosphenes by transcranial alternating current stimulation (tACS) involving the visual cortex.
Methods:
Self-reported phosphene ratings and voltage-related potentials from the canthus, supra-orbital and sub-orbital regions of the right eye were measured to 2, 10 and 20 Hz tACS at 250 and 1000 microA intensities in healthy volunteers.
Results:
Qualitatively similar, but more intense phosphenes were reported during frontalis-vertex tACS as compared to occiput-vertex tACS. In addition, voltage-related potentials were recorded at the canthus and orbit regions of the eye during frontalis-vertex, occiput-vertex and occiput-right shoulder tACS.
Conclusions:
The experience of phosphenes during tACS involving the visual cortex is influenced by volume conductions effects of the scalp.
Significance:
Retinal effects should be taken into account when studying the cortical modulatory effects of tACS.
