Locus coeruleus (LC) is involved in attention and other brain functions. We ascertained how LC activity up-regulation affects brain states derived from a hidden Markov model. Upon up-regulating LC activity, we found increased pupil size during state switching. This may indicate an increase in LC activation during the state switching process. Specifically, significant interactions between state and condition were observed when transitioning into the default mode network, but not into attention networks. The lack of interaction may be due to LC already being active during transitions into the attention network.