The locus coeruleus regulates attention and is an important mediator of stress responses.
It is activated by orexin and sends the norepinephrine it produces to quite a few brain regions involved in stress systems.
- Stimulated by orexin
Afferents (received signals) from:
- Constant stimulating input according to the activity level
- Nucleus paragigantocellularis
- Integrates autonomous and environmental stimuli
- Nucleus prepositus perihypoglossalis
- Controls horizontal and vertical eye movements, gaze following movements and gaze fixation
- Produces orexin
- Produces noradrenaline
- Efferences (sends signals) to:
- Spinal cord
- Tectum (dorsal mesencephalon)
- Ventral tegmentum
Chronic activation of the locus coeruleus appears to reduce the stress response1
Chemical deactivation of the locus coeruleus acutely and briefly reduced the HPA axis response. However, after 4 weeks of chronic stress, the HPA axis response was fully restored despite deactivated LC.2 This suggests that the primarily appears to mediate acute stress responses.
Velley, Cardo, Kempf, Mormede, Nassif-Caudarella, Velly (1991): Facilitation of learning consecutive to electrical stimulation of the locus coeruleus: cognitive alteration or stress-reduction?. Prog Brain Res. 1991;88:555-569. doi:10.1016/s0079-6123(08)63834-0 ↥
Ziegler DR, Cass WA, Herman JP. Excitatory influence of the locus coeruleus in hypothalamic-pituitary-adrenocortical axis responses to stress. J Neuroendocrinol. 1999;11(5):361-369. doi:10.1046/j.1365-2826.1999.00337.x ↥