Jeffrey D. Knotts

TITLE: Using Psychophysics and Decoded Neurofeedback to Investigate Conscious (and Unconscious) Visual Processing

In this talk, I will discuss two lines of work that  investigate two prominent questions about consciousness: Is there such a thing as direct, unconscious visual perception in normal observers? And what is the role, if any, of frontal and parietal areas in conscious visual perception? To address the first question, we followed up on the work of Peters and Lau (2015 eLife) with a series of two-interval forced choice (2IFC) psychophysical experiments comparing the relative masking effects of sandwich masking and continuous flash suppression (CFS). We hypothesized that CFS would be more permissive to unconscious visual processing than sandwich masking, but, contrary to previous findings, we found no such difference between the two masking techniques. To address the second question, we followed up on the work of two previous studies using decoded fMRI neurofeedback (DecNef) (Amano et al., 2016 Curr. Biol.; Cortese et al., 2016 Nat. Commun.) to see if the simultaneous activation of multivariate patterns for color in early visual cortex and high confidence in frontoparietal areas could lead subjects to have illusory color experiences. Our results show that illusory color experience is associated with decoded patterns for confidence in frontoparietal cortex, but not with decoded patterns for color in early visual cortex. We interpret this to suggest a unique role for frontoparietal areas in conscious color perception.

ALL ARE WELCOME.

Read more about JD Knotts at: 
https://shamslab.psych.ucla.edu/people/jd-knotts/
https://shamslab.psych.ucla.edu/