Data from: Locus coeruleus neuromelanin predicts ease of attaining and maintaining neural states of arousal

The locus coeruleus (LC), a small subcortical structure in the brainstem,
is the brain’s principal source of norepinephrine. It plays a primary role
in regulating stress, the sleep-wake cycle, and attention, and its
degradation is associated with aging and neurodegenerative diseases
associated with cognitive deficits (e.g., Parkinson’s, Alzheimer’s). Yet
precisely how norepinephrine drives brain networks to support healthy
cognitive function remains poorly understood – partly because LC’s small
size makes it difficult to study noninvasively in humans. Here, we
characterized LC’s influence on brain dynamics using a hidden Markov model
fitted to functional neuroimaging data from healthy young adults across
four attention-related brain networks and LC. We modulated LC activity
using a behavioral paradigm and also measured individual differences in LC
neuromelanin. The model revealed five hidden states, including a stable
‘arousal’ state that occurred when subjects actively engaged with the
task. LC neuromelanin correlated with this state’s stability across
experimental manipulations and with subjects’ propensity to enter into and
remain in this state. These results provide new insight into LC’s role in
driving spatiotemporal neural patterns associated with attention and
arousal and demonstrate that neuromelanin variation can explain individual
differences in these patterns even in healthy young adults.