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Proc Natl Acad Sci U S A. 2018 Oct 2;115(40):E9439-E9448. doi: 10.1073/pnas.1803716115. Epub 2018 Sep 19.

Phasic locus coeruleus activity regulates cortical encoding of salience information.

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Department of Biology, University of Massachusetts, Amherst, MA 01003;
Department of Psychological and Brain Sciences, University of Massachusetts, Amherst, MA 01003.
Brain Health Institute, Rutgers University, Piscataway, NJ 08854


Phasic activation of locus coeruleus (LC)-norepinephrine (NE) neurons is associated with focused attention and behavioral responses to salient stimuli. We used cell-type-specific optogenetics and single-unit neurophysiology to identify how LC activity influences neural encoding of sensory information. We found that phasic, but not tonic, LC-NE photoactivation generated a distinct event-related potential (ERP) across cortical regions. Salient sensory stimuli (which innately trigger phasic LC activity) produced strong excitatory cortical responses during this ERP window. Application of weaker, nonsalient stimuli produced limited responses, but these responses were elevated to salient stimulus levels when they were temporally locked with phasic LC photoactivation. These results demonstrate that phasic LC activity enhances cortical encoding of salient stimuli by facilitating long-latency signals within target regions in response to stimulus intensity/salience. The LC-driven salience signal identified here provides a measure of phasic LC activity that can be used to investigate the LC's role in attentional processing across species.


ERP; intensity coding; norepinephrine; phasic; somatosensory cortex

[Available on 2019-04-02]
[Indexed for MEDLINE]

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