Title: Dynamic constraints on activity and connectivity during the learning of value,
Abstract: Human learning is a complex process in which future behavior is altered via
the modulation of neural activity. Yet, the degree to which brain activity and
functional connectivity during learning is constrained across subjects, for
example by conserved anatomy and physiology or by the nature of the task,
remains unknown. Here, we measured brain activity and functional connectivity
in a longitudinal experiment in which healthy adult human participants learned
the values of novel objects over the course of four days. We assessed the
presence of constraints on activity and functional connectivity using an
inter-subject correlation approach. Constraints on activity and connectivity
were greater in magnitude than expected in a non-parametric permutation-based
null model, particularly in primary sensory and motor systems, as well as in
regions associated with the learning of value. Notably, inter-subject
connectivity in activity and connectivity displayed marked temporal variations,
with inter-subject correlations in activity exceeding those in connectivity
during early learning and \emph{visa versa} in later learning. Finally,
individual differences in performance accuracy tracked the degree to which a
subject's connectivity, but not activity, tracked subject-general patterns.
Taken together, our results support the notion that brain activity and
connectivity are constrained across subjects in early learning, with
constraints on activity, but not connectivity, decreasing in later learning.