Blue spot in the brain

In the brain there is a blue spot called the locus coeruleus. It is a small pigmented region in the pons of the brainstem- a part of the brain just above the skull base at the back. The blue colouring is caused by the production of a pigment formed by chemical reactions involving the neurotransmitter noradrenaline. This is the principal site for brain synthesis of noradrenaline. This blue spot sends noradrenaline almost to all regions of the brain including mood control regions prefrontal cortex, amygdala and hippocampus. It is involved in physiological responses to stress and panic. Neurons in this blue spot are less active at calm situation and sleep, but their activities are increased in response to alert situation such as stress. In response to stress, the blue spot is activated and produces more noradrenaline to alter cognitive function and activate hypothalamic-pituitary adrenal axis to produce more stress hormones and increase sympathetic nerve activities. It also affects amygdala to induce most stress-induced fear-circuitry disorders, such as anxiety. Aging is associated with a significant loss of neurons in the blue spot.