Neurophysiological mechanisms of experience-dependent perceptual biases using concurrent EEG-fMRI recordings

Abstract

Motivationally relevant compared to irrelevant stimuli show measurable biases in sensory systems. Neurophysiologically, biases have been demonstrated in single-neurons as well as neural mass activity in sensory cortex. One hypothesis states that this modulation of sensory neurons is driven by re-entrant projections from anterior cortical and subcortical structures, but limited empirical evidence exists to support this hypothesis. To address this limitation in the literature, the current project simultaneously collected BOLD and EEG, utilizing their spatial and temporal resolutions, in addition to electrocardiography during a classical conditioning paradigm in which the orientation of grating stimuli (i.e. the conditioned stimulus, CS) predicted the presence (CS+) or absence (CS-) of a cutaneous electric shock (i.e. the unconditioned stimulus, US). Phase reversal of the gratings elicited a steady-state visual evoked potential, which was used to estimate stimulus related visual cortical activity on a single-trial basis. CS+ relative to CS- trials during US pairing were associated with increased ssVEP amplitude, greater heart-rate deceleration, and greater BOLD activation in primary visual, anterior insular, and temporal cortices bilaterally. Modeling BOLD activity using the single-trial ssVEP indices showed specific BOLD-ssVEP coupling in primary and extended visual cortex over all trials, and CS+ relative to CS- specific activation in the calcarine and dorsolateral prefrontal cortices. BOLD signals in bilateral amygdala showed CS+ specific ssVEP coupling early during US pairing. These results suggest that visual cortical responses are amplified as a function of motivational relevance, and that anterior structures relate to fluctuations in visual cortical activity. Future analyses may test the extent to which these extra-visual cortical sites are functionally related visual cortical engagement and if any temporal pattern exists among the engagement of these structures.

Meeting abstract presented at VSS 2016