Current Biology
Volume 19, Issue 21, 17 November 2009, Pages 1799-1805
Journal home page for Current Biology

Report
Preperceptual and Stimulus-Selective Enhancement of Low-Level Human Visual Cortex Excitability by Sounds

https://doi.org/10.1016/j.cub.2009.09.027Get rights and content
Under an Elsevier user license
open archive

Summary

Evidence of multisensory interactions within low-level cortices and at early post-stimulus latencies 1, 2, 3, 4, 5, 6 has prompted a paradigm shift in conceptualizations of sensory organization 7, 8, 9, 10. However, the mechanisms of these interactions and their link to behavior remain largely unknown. One behaviorally salient stimulus is a rapidly approaching (looming) object, which can indicate potential threats 11, 12, 13. Based on findings from humans [14] and nonhuman primates 15, 16 suggesting there to be selective multisensory (auditory-visual) integration of looming signals, we tested whether looming sounds would selectively modulate the excitability of visual cortex. We combined transcranial magnetic stimulation (TMS) over the occipital pole and psychophysics for “neurometric” and psychometric assays of changes in low-level visual cortex excitability (i.e., phosphene induction) and perception, respectively 17, 18. Across three experiments we show that structured looming sounds considerably enhance visual cortex excitability relative to other sound categories and white-noise controls. The time course of this effect showed that modulation of visual cortex excitability started to differ between looming and stationary sounds for sound portions of very short duration (80 ms) that were significantly below (by 35 ms) perceptual discrimination threshold. Visual perceptions are thus rapidly and efficiently boosted by sounds through early, preperceptual and stimulus-selective modulation of neuronal excitability within low-level visual cortex.

SYSNEURO

Cited by (0)

6

These authors contributed equally to this work