The volunteer is instructed to fixate on the dot, and, when ready, to press the space bar on the computer. At this point, the computer flashes three capital letters in the center of the screen and 90 ms later, fires a train of four pulses on the magnetic coil. If the magnet was directed toward the area of visual cortex, then a momentary blind spot in the visual field will occur. The volunteer is asked to report the three letters that he saw on the monitor. Afterwards, the computer reports the actual three letters.
Any discrepancy is considered to be a response and is noted in the results.
In the figures below, red arrows correspond to a suppression in the right visual field, and blue arrows correspond to a suppression in the left visual field. Green arrows indicate no response as the subject correctly reported all three letters. Selected Publications G. Potts, L. Gugino, M.E. Leventon , W.E.L. Grimson , R. Kikinis , W. Cote, E. Alexander. G.J. Ettinger , M.E. Leventon , W.E.L. Grimson , R. Kikinis , V. Gugino, W. Cote, L. Sprung, L. Aglio, M. Shenton, G. Potts, E. Alexander. Experimentation with a Transcranial Magnetic Stimulation System for Functional Brain Mapping.