Cognitive Neuroscience Society Annual Meeting, Boston, MA (April 2014)

Rhythmic Transcranial Magnetic Stimulation (TMS) has demonstrated an ability to enhance brain oscillatory activity at the input frequency. Using this approach, we recently reported that uniform 30 Hz TMS patterns delivered pre-target on the right Frontal Eye Field (FEF) were able to improve the visual detection of near-threshold targets. Here, by recording the effects of these same TMS patterns on a complete psychometric function, we tested if this facilitatory visual impact was restricted to such stimulus contrast or could also be extended to other contrast levels. 14 participants performed a two alternative forced-choice visual task in which they were requested to report the right of left location of a lateralized Gabor. During the trials, participants received on the right FEF and 16 ms prior to target onset, either real/sham 30 Hz bursts or duration-matched non-uniform TMS bursts encompassing the same number of pulses. Participant detection performance for each TMS condition was fitted to a Gumbel function to reconstruct the psychometric curve. In agreement with prior observations, only frequency specific 30 Hz frontal patterns but not non-uniform bursts increased detection rates. Such effect occurred for the upper (i.e.,above 75% performance) but not the lower half of the psychometric curve. Our results support a causal role for frontal high-beta oscillatory activity in the modulation of contrast sensitivity and prove that such facilitatory mechanism is not solely restricted to near threshold targets but can be extended to a wider range of suprathreshold stimulus contrasts.

¹ Centre de Recherche de l’institut du Cerveau et la Moelle Epinière (CRICM)

² Centre National de la Recherche Scientifique (CNRS)

³ Department of Anatomy and Neurobiology, Boston University School of Medicine

⁴ Charles River Analytics