Behavior differs across individuals, ranging from typical to atypical phenotypes. Understanding how differences in behavior relate to differences in neural activity is critical for developing treatments of neuropsychiatric and neurodevelopmental disorders. One hypothesis is that differences in behavior reflect individual differences in the dynamics of how information flows through the brain. In support of this, the correlation of
neural activity between brain areas, termed ‘‘functional connectivity,’’ varies across individuals and is disrupted in autism, schizophrenia, and depression. However, the changes in neural activity that underlie
altered behavior and functional connectivity remain unclear. Here, we show that individual differences in
the expression of different patterns of cortical neural dynamics explain variability in both functional connectivity and behavior. Using mesoscale imaging, we recorded neural activity across the dorsal cortex of behaviorally ‘‘typical’’ and ‘‘atypical’’ mice. All mice shared the same recurring cortex-wide spatiotemporal motifs of
neural activity, and these motifs explained the large majority of variance in cortical activity (>75%). However,
individuals differed in how frequently different motifs were expressed. These differences in motif expression
explained differences in functional connectivity and behavior across both typical and atypical mice. Our results suggest that differences in behavior and functional connectivity are due to changes in the processes
that select which pattern of neural activity is expressed at each moment in time.