Our work combines visual psychophysics and Transcranial Magnetic Stimulation (TMS); a non-invasive brain stimulation technique that applies using an electromagnetic coil placed on the scalp.
We also utilise a 3D neuronavigation system guided by MRI and fMRI data to accurately stimulate a target brain area.
Can TMS improve the detection of visual stimuli? TMS is usually employed to impair visual perception. Here we demonstrate improvement in visual detection using TMS pulse applied below the phosphene threshold.
Should we characterise the functional effect of TMS as noise induction or signal suppression? Data from two studies using either static or moving stimuli are better explained as signal suppression than as noise induction in the brain.
We have implemented an adaptive staircase procedure to rapidly and accurately estimate phosphene thresholds. The procedure is implemented in Matlab and is available for download.