Chemogenetic stimulation of tonic locus coeruleus activity strengthens the default mode network
Science Advances April 1, 2022 E. Oyarzabal, Li-Ming Hsu, Manasmita Das et al.
Activating norepinephrine-releasing neurons in the locus coeruleus (LC) of the mouse brain alters the default mode network (DMN). Chemogenetic stimulation of these neurons decreased cerebral blood volume and glucose uptake while increasing synchronous low-frequency fMRI activity in the frontal cortices of the DMN. Fiber photometry confirmed that LC-NE activation triggered norepinephrine release, enhanced calcium-weighted neuronal spiking, and reduced cerebral blood volume in the anterior cingulate cortex. These findings indicate that LC-NE changes the typical relationship between neuronal activity and blood volume in the frontal DMN. The activation also strengthened functional connectivity within the frontal DMN, an effect mediated by reduced inputs from retrosplenial and hippocampal regions.