To many people, the brain is simply a singular thing. A big lump of grey stuff - or pink stuff if you actually get a chance to see a fresh one.
But for those who learn about the brain, the first distinction to be made out is that it has lines, or creases, which run through it, and these are
called sulci (creases) and gyri (bumps), which I like to think of in terms of the bottom of a wave (trough) and the top of a wave (crest).
The four main fissures, or grooves, create four separate lobes, each having evolved to discriminate a particular mode of being: vision is in the back
(occipital cortex), where you are, or your place-in-a-3-dimensional-environment, is processed at the top of your head (parietal cortex); hearing is at
the sides of your head (temporal cortex) and thinking and planning is in the front of your head (frontal cortex).
Four islands, as it were, have 'separated', but all are united below the cortex itself, via connections running from each area into the thalamus and
the midbrain connections they connect with. If there could be said to be a "uniting fifth", like the affect which runs 'beneath' our cognitions about
reality, the mid-brain regions of the hippocampus, amygdala, bed-nucleus of the stria-terminalis (BNST), the striatum, hypothalamus, and brainstem,
more or less constrain all living beings into being a version of the same exact process: homeostatic regulation of the whole through correlating the
various cycles which make up its dynamical structure.
On the outside, me, a bird and the grass I walk upon look very different; but on the inside, the same chemical-dynamics i.e. autocatyltic loops which
'know' how to process energy, and so, maintain their cycling, are never-ending in their pursuit of being.
“These cycles happened, as they continue to happen, all at once – that is, simultaneously. They naturally carried forward together. All the cycles
we lived with and within – from the skies to the world around us to the smallest creatures – happened, if you will allow a grand term for a
fundamentally normal occurrence, in symphony. They were a universality – perhaps, the universality – of our world.” – Irv Dardik, The Nature
of Nature: The Discovery of Superwaves and how it Changes Everything; pg. 5, Rodale, 2017
This idea of coherence underlies any meaningful conversation about how reality actually works. In a coherent society, it'd be a central, orienting
device for everything we do; and likewise, in a incoherent, disordered, intellectually and existentially blasé world, coherency is barely recognized
or noted - and why? Symmetry is the ordering principle regardless of what we do, which means todays society is one where certain values and ways of
being serve as "existential hooks" which act upon the affective dynamism of bodies - and the minds they give rise to - and together, bodies mutually
assimilate and entrain to the orienting mental object, while at the same time modifying it by creating new connections that offer vantage points
capable of pulling the whole in new and more coherent directions.
Brain As A Model for Society
The brain is a logically constructed structure, and it should be, given symmetry dynamics are what becomes 'selected' by natural selection; and so,
the only states which are able to 'survive' and progress are those in some existential 'balance' with an affordance found within the environment the
Inside the human skull, in the brain, at its general center, lies the brains "headlights": the amygdala
The amygdala exists as two bulbous protrusions that stick out from the seahorse shaped hippocampi (plural for hippocampus; there is one on each side).
It is ideally located so that each of the sensory areas (visual, audial, proprioceptive, interoceptive), the motor/brainstem areas for movement, and
the frontal area for thinking and regulating, are informed by the amygdala's judgements, which, upon further analysis, are in themselves very complex.
The amygdala is a distinct neurological body with around 12-15 million neurons. That is a pretty large number; and they're extraordinarily active.
The above chart describes the basic dynamics of cellular populations within the brain relevant to the stress response in animals. First, sensory areas
inform the lateral amygdala, which passes on its 'info' to the basal area, which forwards this info to the central lateral and medial areas of the
amygdala. Each group, or area, have slightly different chemical profiles, and so, activate or inhibit activity in different ways. Complex - yes, but
From the central medial amygdala "outputs" move to the BNST, which controls the motor response as it pertains to the threat at hand, as well as the
periaqueductal grey, which helps support the "numbing" of the freeze response, by releasing endogenous opiates which come to color the experience of
consciousness. From the central lateral amygdala outputs move to the pontis caudalis, which mediates the startle response (these sorts of things are
figured out by destroying anatomically unique areas, and seeing what turns up at the behavioral level). Thus, the central amygdala (central nucleus in
the above chart) completely - and automatically - moves our body into a particular configuration via it's direct connections with the amygdala.
The amygdala, also, seems to be supplemented in its logic as a threat system by the BNST itself. Logically speaking, the amygdala's direct inputs are
from the sensorial parts of the brain i.e. vision, sound, and the bodies movement in the environment, which are the back, sides, and top of our brain
respectively. The amygdala is therefore "sensory" oriented.
Conversely, the bed nucleus of the stria terminalis is connected with the motor outputs which control how the body organizes itself, as well, via its
connections with the hippocampus and paraventricular nucleus, is also what triggers the HPA axis - or the stress response system of the body. The BNST
is therefore "action" oriented, in both organizing and directing other areas to organize for a threat response.
In the nature of our experience of social stress, for instance, we can see the amygdala as that element in our experience which orients us to pay
attention to that object - of a largely 'cognitive" nature - which exists in our environment. Conversely, the BNST is that element of the fear
response which compels us to pay attention to our bodies i.e. as an 'internal referent', which effectively 'motivates' the self to act. As a way of
thinking about emotion, it is interesting that the amygdala, which is typically associated with "emotionality", would be more cognitive and "up"
oriented, relative to the BNST, which is deeper in the brain, and as our experience reveals (as well as a grievously overwhelming number of studies)
is 'downward' - towards acting on the world.
Neither Good Nor Bad: Just Survival
What's interesting about these brain areas is that, being built from the 'ground-up', they are geared towards survival, and hence, the BNST's
connections with the paraventricular nucleus of the hypothalamus, which mediates both stress response, as well as registering homeostatic realities
such as hunger/satiation, and so, compelling changes in feeling (in the body) in terms of what the dynamics of the bodies states are reporting.
edit on 23-9-2017 by Astrocyte because: (no reason given)