Locus Coeruleus, Vigilance and Stress: Brain Mechanisms of Adaptive Behavioral Responsiveness
Annual technical rept. 28 Feb 1992-30 Dec 1993
HAHNEMANN UNIV PHILADELPHIA PA DEPT OFMENTAL HEALTH SCIENCES
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We have recorded electrical activity from more than 200 neurons in the locus coeruleus LC in 2 behaving monkeys during the last year. We have made significant technical advances e.g., use of 10 micrometers-diameter microwires for recordings, increased accuracy of electrode penetrations which have increased the quality and quantity of data obtained. Results confirm our preliminary findings of the last period, i.e., LC neurons vary activity physically and tonically during a vigilance task indicating a role for the LC system in regulating attentional lability and adaptive responsiveness to urgent stimuli. Moreover, extensive analysis of reversal performance reveals that LC neurons may have a close relationship with cognitive processes underlying stimulus analysis and decision-making. Finally, this analysis also reveals that LC neurons alter their responsiveness to stimuli after reversal of cue meaning in advance of corresponding alterations in behavioral responsiveness, indicating that LC neurons may play an important role in early learning processes, helping to entrain other brain systems to respond adaptively to new significant stimuli.
- Anatomy and Physiology