Amygdala or AmyG, the always on guard dog of your nervous system takes information from sensory systems, bilateral amygdala (BLA), insular cortex, and the periaqueductal gray (PEG) to name but a few. The information doesn’t stop there as there is either reaction to the information or it is recognised and then ignored. Here we look at the outputs from AmyG.

First of AmgG talks back to all of here friends already mentioned controlling how they work and refining the messaging depending on the state of AmgG at the time.

HippoC – Hippocampus (Sea Monster Horse)

Recalling Fear

The next one, and its a bigger is the hippocampus or HippoC. HippoC (latin for Sea monster (campus) and horse (hippos) because it looks a little bit like a seahorse) can be seen as the opposite of AmyG. Where AmyG will quickly react to something she has detected HippoC likes to take his time and check things before making a decision. However, AmgG is quite a forceful character and can make HippoC move a little quicker as sometimes taking your time is not a good idea.

AmyG and friend Notorious BLA work on caution at one level, fear at the extreme. Fear aims to keep us alive by running away from danger (fighting is oftent the last or the lust resort – little neurobiology joke there). HippoC is responsible for learning and therefore retrieval of information including stuff to be afraid of from the common like snakes (ophidiophobia) to any personal phobias. The learning is based on very big life experiences that, having gone through it, you will want to remember for experience. Events that were scary are the ones that AmyG is looking out for. For example imagine crossing the road and just making it across. Your heart would be pounding, might be sweating, and certainty trying to remember how you got into that position: time of night, place in the world, who you were with, colour of the car etc. All of this information is recalled by HippoC.

It’s worth noting that the ability to store the information about an event can be impeded. Many drugs will inhibit memory but the most common for not remembering events is alcohol. Too much alcohol can have a double effect on behaviour as it inhibits fears and prevents memory formation to stop you doing it in the future leading to events of ‘how did I get here and how did I break that?’ Don’t ask AmyG or HippoC as you kept them out of the evening events.

We’ll be talking about HippoC much more but for now let’s move on.

Muscles and Motors – Movement

Getting information in, detecting it as something to aware of and then doing nothing is not very helpful. Most often AmyG nags at the grown-up frontal cortex (FrontC) trying to get FrontC’s attention. AmyG tends to be get a lot of things over the top with FrontC over riding a call to action as this is how AmyG works with FrontC.

Sometimes due to the urgency of the situation AmyG has permission to go past FrontC and action the parts that FrontC would normally talk to namely SubCortical made up of several parts  (diencephalon, pituitary gland, limbic structures and the basal ganglia) , and the reflexive motor pathways that move us through muscle contraction. This bypassing means we can move fast at a threat which can be great: ok, phew – so it turns out it was falling bush not a massive bear attacking me. But it can also be tragic: I thought it was a burglar so I pushed the person down the stairs/ jumped out of the window to escape when it was a friend coming home unexpected (perhaps you can also see that those learned fears are a problem in these circumstances).

The normal process is that messages got to the central amygdala (CAmyG) which then go to the easy to remember Bed Nucleus of the Stria Terminalis (BNST) or, slightly easier to remember Extended AmyG (EAmyG) which then pass information to the daddy of hormonal control and response the hypothalamus (HypoT) which triggers the flee-fight sympathetic (emotional) nervous system and inhibits the rest-digest parasympathetic (chilled) nervous systems.

Another friend and output of AmyG is a very old friend that lives in an old part of the brain the Brain Stem. Locus coeruleus (LociC) (spot, blue) is like a sympathetic (emotional, F&F) nervous system for your brain doing what the body sympathetic system does by telling the rest of the brain to wake up and be ready for something with that something being bad (not being eaten) or good (making more of oneself 😉 ). It does this through the release of norepinephrine (naw-epi-neff-rin) which dilated the blood vessels to allow more oxygen and glucose in and carbon dioxide out.

In summary AmyG has many friends that she talks to make sure you stay alive. FrontC checks things aren’t over the top when it’s not instant danger, HippoC gives details to scary events to check what to expect and do, Bed Nucleus of the stria terminalis which supports messaging to other parts of the limbic system including the hypothalamus which promotes the release of hormones and finally Locus coeruleus that prepares the brain itself for action.

Next the thinking persons cortex – the Frontal Cortex.