Context-dependent relationships between locus coeruleus firing patterns and coordinated neural activity in the...

Area of Science:

• Neuroscience
• Systems Neuroscience
• Cognitive Neuroscience

Background:

• The locus coeruleus (LC) is a key neuromodulatory center.
• Norepinephrine (NE) released by the LC influences cortical networks.
• The precise in vivo effects of LC-NE on neural activity patterns remain unclear.

Purpose of the Study:

• To investigate how LC activation affects coordinated neural activity in the anterior cingulate cortex (ACC) in awake monkeys.
• To determine if these effects depend on the pattern of LC activation.
• To explore the relationship between LC-NE system modulation, neural coordination, and arousal.

Main Methods:

• Electrophysiological recordings in awake behaving monkeys.
• Monitoring of neural activity in the ACC.
• Stimulation and recording of the LC.
• Analysis of pairwise neuronal correlations and firing rates.
• Pupillometry to assess arousal.

Main Results:

• LC activation altered coordinated activity patterns in the ACC.
• Reduced ACC pairwise correlations with increased baseline LC activity.
• Enhanced ACC pairwise correlations with transient LC responses.
• These modulations were largely independent of individual ACC neuron firing rates.
• Relationships covaried with arousal-dependent pupil changes.

Conclusions:

• LC-NE system activation dynamically modulates neural coordination in the ACC.
• The effects are context-dependent, varying with ongoing versus event-evoked LC activity.
• Arousal and context-dependent LC activity changes contribute to altered cortical information processing.