Fast and Localized Event-Related Optical Signals (EROS) in the Human Occipital Cortex: Comparisons with the Visual Evoked Potential and fMRI

Gabriele Gratton, Monica Fabiani, Paul M Corballis, Donald C Hood, Marsha R Goodman-Wood, Joy Hirsch, Karl Kim, David Friedman, Enrico Gratton
1997 NeuroImage  
Localized evoked activity of the human cortex produces fast changes in optical properties that can be detected noninvasively (event-related optical signal, or EROS). In the present study a fast EROS response (latency E100 ms) elicited in the occipital cortex by visual stimuli showed spatial congruence with fMRI signals and temporal correspondence with VEPs, thus combining subcentimeter spatial localization with subsecond temporal resolution. fMRI signals were recorded from striate and
more » ... riate and extrastriate cortex. Both areas showed EROS peaks, but at different latencies after stimulation (100 and 200-300 ms, respectively). These results suggest that EROS manifests localized neuronal activity associated with information processing. The temporal resolution and spatial localization of this signal make it a promising tool for studying the time course of activity in localized brain areas and for bridging the gap between electrical and hemodynamic imaging methods. 1997 Academic Press Key Words: noninvasive optical imaging; eventrelated optical signal (EROS); fMRI; VEPs; functional brain mapping; photon migration in tissues.
doi:10.1006/nimg.1997.0298 pmid:9344821 fatcat:pcd7nsjw2ffadpv6iksecaijrm