Assessing the function of late-stage cortical processing regions, such as prefrontal cortex, is notoriously challenging. Yet it is these areas that are hypothesized to subserve complex higher-order processes including self-evaluation of decisional uncertainty and even perceptual awareness. How can we measure the degree to which late-stage cortical processing areas have access to the representational content in sensory regions in humans? Assessing time-varying functional connectivity from prefrontal to lower-level sensory areas via fMRI is challenging with conventional approaches, and suffers from poor temporal precision. In this talk, I will present a new dynamic functional connectivity metric, based on information theory, that we are developing. The metric relies on 40-way multinomial sparse logistic regression decoding, capitalizing on a 70-subject database. I will discuss how trial-by-trial functional connectivity between prefrontal and low-level sensory areas may predict prefrontal access, how this metric could change as a function of training using real-time fMRI and decoded neurofeedback, and challenges we have uncovered. These results may shed new light on the critical role played by prefrontal cortex in making a low-level sensory representation available to higher order processing.

Prof. Megan Peters