Learning differentially reorganizes brain activity and connectivity

Abstract

Human learning is a complex process in which future behavior is altered via the reorganization of brain activity and connectivity. It remains unknown whether activity and connectivity differentially reorganize during learning, and, if so, how that differential reorganization tracks stages of learning across distinct brain areas. Here, we address this gap in knowledge by measuring brain activity and functional connectivity in a longitudinal fMRI experiment in which healthy adult human participants learn the values of novel objects over the course of four days. An increasing similarity in activity or functional connectivity across subjects during learning reflects reorganization toward a common functional architecture. We assessed the presence of reorganization in activity and connectivity both during value learning and during the resting-state, allowing us to differentiate common elicited processes from intrinsic processes. We found a complex and dynamic reorganization of brain connectivity and activity-as a function of time, space, and performance-that occurs while subjects learn. Spatially localized brain activity reorganizes across the brain to a common functional architecture early in learning, and this reorganization tracks early learning performance. In contrast, spatially distributed connectivity reorganizes across the brain to a common functional architecture as training progresses, and this reorganization tracks later learning performance. Particularly good performance is associated with a sticky connectivity, that persists into the resting state. Broadly, our work uncovers distinct principles of reorganization in activity and connectivity at different phases of value learning, which inform the ongoing study of learning processes more generally.Although each human brain is unique, all brains share a common form. Functional connectivity, which measures the statistical similarity between the temporal activity of two brain regions, can vary appreciably across individuals, so much so that it serves as an individual's fingerprint 1 . Moreover, recent work has demonstrated that functional connectivity can predict task performance 2 , including the capacity for skill learning 3-5 . Similarly, a single cognitively demanding task can elicit quite different patterns and magnitudes of activity in different individuals 6 . Finally, individual differences in functional connectivity during rest are related to individual differences in brain activity during task performance 7 . Despite these notable instances of variance in brain activity and connectivity, there also exist several invariable subject-general patterns; macro-organizational principles of functional connectivity appear to be conserved throughout healthy normative populations 8,9 , and there are reliable group level task-induced organizations of brain activity 10 and functional connectivity 9 .Similarly, learning is a dynamic process with both similarities and differences across individuals; everyone learns differently, but much of the mechanics of learning ...

Fear extinction learning modulates large-scale brain connectivity

“…This is well-aligned with the current view that brain function depends on highly complex interactions between distributed brain regions ( Sporns, 2014 ; Braun et al, 2018 ). Some preliminary studies, though not in the context of fear learning, have shown that learning will extensively reorganize brain activation and connectivity ( Bertolero et al, 2020 ). Together, these data suggest that broadly distributed brain regions are likely engaged during the extinction of conditioned fear responses.…”