Individual choices shape divergent brains and behaviors

Individual choices shape life course trajectories of brain structure and
function beyond genes and environment. We hypothesized that individual
task engagement in response to a learning program results in
individualized learning biographies and connectomics. Genetically
identical female mice living in one large shared enclosure freely engaged
in self-paced, automatically administered and monitored learning tasks. We
discovered growing and increasingly stable inter-individual differences in
learning trajectories. Adult hippocampal neurogenesis and connectivity as
assessed by a high-density multi-electrode array positively correlated
with the variation in exploration and learning efficiency. During some
tasks, divergence transiently collapsed, highlighting the sustained
significance of context for individualization. Thus, equal environments
and equal genes do not result in equal learning biographies because life
confronts individuals with choices that lead to divergent paths.