Distinct ensembles in the noradrenergic locus coeruleus evoke diverse cortical states

The noradrenergic locus coeruleus (LC) is crucial for controlling brain and behavioral states. While synchronous stimulation of LC neurons evokes a single activated cortical state with increased high-frequency power, little is known about how spontaneous patterns of LC population activity drive cortical states. Since LC neurons selectively project to specific forebrain regions, we hypothesized that individual LC ensembles produce different cortical states. We recorded up to 34 single units simultaneously in the rat LC and used non-negative matrix factorization to identify spontaneously activated ensembles of co-active LC neurons. The ensembles were active mostly at different times and were simultaneously active only rarely. We assessed cortical state in area 24a by examining local field potential power spectrograms triggered on activations of individual LC ensembles. We observed four spectrotemporally-distinct cortical states associated with activation of specific LC ensembles. Thus, distinct spontaneously active LC ensembles contribute to unexpectedly diverse cortical states