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All parts of the brain › Brain chemicals › Noradrenaline

Where is noradrenaline (norepinephrine) made in the brain?

Noradrenaline, also called norepinephrine, is made in the brain mainly by the locus coeruleus, a small nucleus of about 15,000 neurons in the pons of the brainstem. From there its fibres reach every major part of the brain and the spinal cord, among them the cerebral cortex, hippocampus, amygdala, thalamus, hypothalamus and cerebellum. [1][2]

The 3D brain needs JavaScript. The lists below still say where noradrenaline is made and where it is sent.

Lit: the parts that hold the cells making noradrenaline (blue) and the parts it is sent to (orange).

Slice

Where noradrenaline is made is lit in blue, where it is sent in orange. Drag to turn, pinch or scroll to zoom; tap a part or a “light” button to name it on its own; .

Not separate shapes in this atlas; lit: the parts that hold them. Lit in blue: the whole pons, which holds the locus coeruleus; the cell groups that make noradrenaline are too small to be shapes in the BodyParts3D model, so nothing is drawn at a guessed point. [2][1]

Lit in orange: the hippocampus, amygdala, thalamus, hypothalamus, cerebellum and spinal cord (central canal), where its fibres end. The fibres themselves are not drawn: the two colours show where the cells are and where they send noradrenaline, not the routes in between. [3]

Made in: lit in blue

  • Locus coeruleus, lit as the pons: A small nucleus at the back of the upper (rostral) pons, in the side of the floor of the fourth ventricle, one on each side: the most important source of the brain’s noradrenaline (cell group A6). It sits inside the pons, so the pons is lit. [2][1]

Sent to: lit in orange

  • Hippocampus (LC → Amygdala and Hippocampus): Reached by the locus coeruleus’s fibres. [2]
  • Amygdala (LC → Amygdala and Hippocampus): Reached by the locus coeruleus’s fibres; the amygdala also sends fibres back to it. [2]
  • Thalamus (LC → Thalamus): Its relay nuclei are reached; they are not separate shapes here, so the whole thalamus is lit. [2]
  • Hypothalamus (LC → Hypothalamus): Reached by the locus coeruleus, and in turn one of its main inputs: the hypothalamus sends fibres back to it. [2]
  • Cerebellum (LC → Cerebellum): Reached by the locus coeruleus, and it projects back to it as well. [2]
  • Spinal cord (LC → Brain stem and Spinal cord): The locus coeruleus sends fibres down to it; two smaller noradrenaline groups lower in the brainstem (A5 and A7) project mainly here. [2][1]
  • Not lit as a target: the cerebral cortex, which the locus coeruleus reaches widely. Lighting all of it would hide the deeper targets, so it is left grey; see the cortex lobe by lobe on the lobes page. [2]
  • Not lit as sources: the smaller noradrenaline cell groups lower in the brainstem, A1 in the medulla and A2 in the solitary nucleus, which also make it; the locus coeruleus is the most important one. [1]

The pathways, as the sources name them

  • LC → Cerebral cortex, from the locus coeruleus forward to the cerebral cortex (not lit; see below). Noradrenaline from the locus coeruleus has an excitatory effect on most of the brain, mediating arousal and priming neurons to respond to stimuli. [2] See What part of the brain controls attention?
  • LC → Amygdala and Hippocampus, from the locus coeruleus forward to the amygdala and hippocampus. In the brain, noradrenaline enhances the formation and retrieval of memory. [2][1] See What part of the brain controls memory?
  • LC → Thalamus, from the locus coeruleus up to the thalamic relay nuclei. One of the forebrain targets of a system that, when active, affects large areas of the brain at once. [2][1]
  • LC → Hypothalamus, from the locus coeruleus up to the hypothalamus. A two-way link: the hypothalamus is one of the locus coeruleus’s inputs, and in stress noradrenaline drives the hypothalamus to release corticotropin-releasing factor, the first step of the hormone chain to the adrenal glands. [2] See What part of the brain controls hormones?
  • LC → Cerebellum, from the locus coeruleus back to the cerebellum. The locus coeruleus–noradrenaline system modulates cerebellar circuits as well as cortical and subcortical ones. [2]
  • LC → Brain stem and Spinal cord, from the locus coeruleus down through the brainstem (lit in blue here only where it holds the source) to the spinal cord. The system modulates brainstem and spinal cord circuits too. [2]

Good to know

  • Noradrenaline and norepinephrine are the same molecule: “norepinephrine” is the usual name in the United States, “noradrenaline” in the United Kingdom and most of the world. [1]
  • Tiny but far-reaching: about 15,000 neurons in primates, less than one-millionth of the brain’s neurons, yet they project to every major part of the brain and to the spinal cord. [1]
  • Sleep and waking: its release is lowest during sleep, rises during wakefulness and is much higher in stress or danger (the fight-or-flight response); locus coeruleus activity drops to virtually nothing in REM sleep. [1] See What part of the brain controls sleep?
  • “Locus coeruleus” is Latin for “blue spot”: neuromelanin, formed from noradrenaline inside its neurons, gives it a blue colour in unstained brain tissue. [2]
  • The brain makes its own supply: the noradrenaline outside the brain comes from sympathetic nerves and from the adrenal glands, which release it into the blood. [1]

What it takes part in

Each lit with every part that takes part: What part of the brain controls attention? · What part of the brain controls sleep? · What part of the brain controls memory? · What part of the brain controls hormones?

Where it is made, each on its own page: Locus coeruleus.

Sources

  1. Wikipedia: Norepinephrine
  2. Wikipedia: Locus coeruleus
  3. BodyParts3D 4.0 (3D model measured on this page), © DBCLS, CC BY-SA 2.1 Japan

Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); the cell groups that make noradrenaline have no shape in it, so the parts that hold them are lit. Real brains vary.