Furthermore, the checkerboard VEPs were modulated topographically between 243 and 296 ms post-stimulus onset as a function of stimulus duration, indicative of the engagement of distinct configuration of active brain networks. When the checkerboards were replaced by blank stimuli, there was no evidence for the presence of an evoked response anymore.
Results revealed that unmasked checkerboards presented subliminally for 250 µs evoked weak but detectable visual evoked potential (VEP) responses. Stimulus visibility was assessed in a third separate behavioral experiment. In this study, we used high density 256-channel EEG coupled with an liquid crystal display (LCD) tachistoscope to characterize the spatio-temporal dynamics of the brain response to visual checkerboard stimuli (Experiment 1) or blank stimuli (Experiment 2) presented without a mask for 1 ms (visible), 500 µs (partially visible), and 250 µs (subliminal) by applying time-wise, assumption-free nonparametric randomization statistics on the strength and on the topography of high-density scalp-recorded electric field. Subliminal perception is strongly associated to the processing of meaningful or emotional information and has mostly been studied using visual masking. Sperdin, Holger F Spierer, Lucas Becker, Robert Michel, Christoph M Landis, Theodor Submillisecond unmasked subliminal visual stimuli evoke electrical brain responses. Linear descriptive modeling of the VER has not yet been shown to provide consistent and readily interpretable results.
#Retroactive neurotracker cpd manual
Model-based phase unwrapping appears to be most reliable in applications, such as manual control, where theoretical models are available. Two aspects of linear modeling are reviewed: (1) unwrapping the phase-shift portion of the frequency response, and (2) parsimonious characterization of task-loading effects in terms of changes in model parameters. Application of linear descriptive modeling to steady state Visual Evoked Response (VER) data is summarized. Kenner, K.Ī study is being conducted to explore use of the steady state visual-evoke electrocortical response as an indicator of cognitive task loading. Descriptive Linear modeling of steady-state visual evoked response
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