Abstract
Functional and electrophysiological measures indicate visual cortical responses evoked by emotionally arousing versus neutral stimuli are amplified, a process thought to be mediated by re-entrant projections from anterior cortical and subcortical structures. In healthy human observers, neuroimaging techniques with high temporal and spatial resolution are necessary to test such hypotheses. Here, blood-oxygen level dependent (BOLD) data and EEG data were collected simultaneously during a classical conditioning paradigm in which the orientation of grating stimuli (the conditioned stimuli, CS) predicted the presence/absence of a cutaneous electric shock (i.e., the unconditioned stimulus). Gratings were phase-reversed for a duration of 5 seconds, at a fixed rate (10/sec), evoking steady-state visual evoked brain potentials (ssVEP). In addition to considering the ssVEP and fMRI data separately, electrophysiological indices of single-trial visual engagement were extracted from ssVEP data and used to construct a predictive model for BOLD activation. BOLD and ssVEP data converged to show specific engagement of circumscribed areas in the calcarine fissure and occipital pole, in response to the phase reversal. Across experimental phases, BOLD in regions such as middle-temporal cortex, anterior insular cortex, and frontal cortical regions related to trial-by-trial fluctuations in ssVEP amplitude.
Meeting abstract presented at VSS 2015