Context-Dependent Relationships between Locus Coeruleus Firing Patterns and Coordinated Neural Activity in the Anterior Cingulate Cortex

Abstract

Ascending neuromodulatory projections from the locus coeruleus (LC) affect cortical neural networks via the release of norepinephrine (NE). However, the exact nature of these neuromodulatory effects on neural activity patterns in vivo is not well understood. Here we show that in awake monkeys, LC activation is associated with changes in coordinated activity patterns in the anterior cingulate cortex (ACC). These relationships, which are largely independent of changes in firing rates of individual ACC neurons, depend on the type of LC activation: ACC pairwise correlations tend to be reduced when tonic (baseline) LC activity increases but are enhanced when external events drive phasic LC responses. Both relationships covary with pupil changes that reflect LC activation and arousal. These results suggest that modulations of information processing that reflect changes in coordinated activity patterns in cortical networks can result partly from ongoing, context-dependent, arousal-related changes in activation of the LC-NE system.

Coupling of pupil- and neuronal population dynamics reveals diverse influences of arousal on cortical processing

“…Pupil-linked arousal exerts pivotal influences on the states of sensory cortices (McGinley, David, et al, 2015; Reimer et al, 2014; Vinck et al, 2015) and associative cortical regions (Joshi & Gold, 2020). However, subcortical arousal systems also project to a wealth of other regions across the cerebral cortex.…”

Locus Coeruleus Norepinephrine in Learned Behavior: Anatomical Modularity and Spatiotemporal Integration in Targets

“…This depolarization in the presence of NE normally leads to an increase in firing rate of neurons and ultimately, increased sensory sensitivity ( Polack et al, 2013 ). In prefrontal cortex regions such as the anterior cingulate cortex and limbic cortex, local manipulation of NE activity influences sustained attention ( Berridge et al, 2012 ; Spencer and Berridge, 2019 ), memory ( Berridge et al, 2012 ; Spencer and Berridge, 2019 ), decision making, and task acquisition ( Tait et al, 2007 ; Tervo et al, 2014 ; Cope et al, 2019 ; Joshi and Gold, 2019 ). NE release in the anterior cingulate cortex promotes exploration and behavioral variation ( Tervo et al, 2014 ).…”

Pupillometry: Arousal State or State of Mind?

“…Another key question is about how these neuromodulators affect the neural circuits in brain regions to which they project. The timing (transient versus gradual) of LC-NE activation can dynamically sculpt the coordinated activity of populations of neurons and influence behavior, thus affecting the information encoding capacity of networks that are active during goaldirected behaviors 11,12 . Are these effects similar in the dorsal raphe nucleus-5HT and BF-ACh systems?…”