Delineating implicit and explicit processes in neurofeedback learning

Abstract

Neurofeedback allows humans to self-regulate neural activity in specific brain regions and is considered a promising tool for psychiatric interventions. Recently, methods have been developed to use neurofeedback implicitly, prompting a theoretical debate on the role of awareness in neurofeedback learning. We offer a critical review of the role of awareness in neurofeedback learning, with a special focus on recently developed neurofeedback paradigms. We detail differences in instructions and propose a fine-grained categorization of tasks based on the degree of involvement of explicit and implicit processes. Finally, we review the methods used to measure awareness in neurofeedback and propose new candidate measures. We conclude that explicit processes cannot be eschewed in most current implicit tasks that have explicit goals, and suggest ways in which awareness could be better measured in the future. Investigating awareness during learning will help understand the learning mechanisms underlying neurofeedback learning and will help shape future tasks.

Value Shapes Abstraction During Learning

“…Decoded neurofeedback is a form of neural reinforcement based on real time fMRI and multivoxel pattern analysis. It is the closest approximation to a non-invasive causal manipulation, with high levels of specificity and administered without participants’ awareness 48–50 Such reinforcement protocols can reliably lead to behavioural or physiological changes that last over time 51–54 We used this procedure in a follow-up experiment (N = 22) to artificially add value (rewards) to neural representation in VC of a target task-related feature (e.g. the orientation; Figure 6A, see Methods).…”

“…More importantly, the results of the decoded neurofeedback manipulation question this interpretation. Because decoded neurofeedback operates unconsciously 48,50 , value was added directly at the sensory representation level (limited to the targeted region), precluding alternative top-down effects. That is not to say that attention does not play a significant role in mediating this type of abstract learning; however, we argue that attention is most likely to be an effector of the abstraction and valuation processes 68 .…”

“…Decoded neurofeedback is a form of neural reinforcement based on real time fMRI and multivoxel pattern analysis. It is the closest approximation to a non-invasive causal manipulation, with high levels of specificity and administered without participants' awareness [48][49][50] . Such reinforcement protocols can reliably lead to behavioural or physiological changes that last over time [51][52][53][54] .…”

“…Decoded neurofeedback is a form of neural reinforcement based on real time fMRI and multivoxel pattern analysis. It is the closest approximation to a non-invasive causal manipulation, with high specificity and administered without participants' awareness (49)(50)(51).…”

“…More importantly, the results of the decoded neurofeedback manipulation question this interpretation. Because decoded neurofeedback operates unconsciously(49,51), value was added directly at the sensory representation level (limited to the targeted region), precluding alternative top-down effects.That is not to say that attention does not play a significant role in mediating this type of abstract learning; however, we argue that attention is most likely to be an effector of the abstraction and valuation processes(70). A simpler top-down attentional effect was indeed evident in the supplementary analysis comparing feature decoding in the 'relevant' and 'irrelevant' cases (Figure S6A): occipital regions displayed large effect sizes (irrespective of the learning strategy used to solve the task).While valuation and abstraction appear tightly associated in reducing the dimensionality of the task space, what is the underlying mechanism?…”