Thursday, December 12, 2013

Hypothesis: The Cultural Amygdala - 3

It is all about connections
In this series we are contemplating the neural network of brain circuitry that develops in humans influenced primarily by their culture.

I am calling it "the cultural amygdala," pointing out that it is composed of circuitry which lies outside of the physical amygdala  (Hypothesis: The Cultural Amygdala), but which connects to the physical amygdala's circuitry.

That connecting circuitry is composed of neurons with their long axons which end at dendrites.

There they connect to other neurons in the physical amygdala via "connections" which take place at synapses, those bridges over the gap between dendrites at the end of axons of other neurons.

Neurons that have their soma (cell body) in other sections of the limbic system of the brain (see e.g. The Brain).

As it turns out, the final basic circuitry that makes up the hypothesized cultural amygdala, within the prefrontal cortex portion of the cultural amygdala, does not begin to develop within us during childhood.

That generally begins in late adolescence and then generally matures during early adulthood:
The first realm to consider where PFC [pre-frontal cortex] function is compromised in humans is, quite reasonably, during development. Children show only minimal frontal function, from the standpoints of cognition (for example, in reversal tasks), emotional regulation, control of impulsive behaviour and moral reasoning. One of the myths of child development is that the brain is fully developed at some remarkably early age (the age of 3 years is probably most often cited (Bruer 1999)). Instead, brain development is far more prolonged and, not surprisingly, the PFC is the last region of the brain to fully myelinate. Remarkably, this process extends well beyond adolescence into early adulthood (Paus et al. 1999).
(The Frontal Cortex and the Criminal Justice System, PDF, p. 6). Dr. Robert Sapolsky of Stanford, in the video below, discusses the Limbic System, which contains the circuitry of the cultural amygdala as well as lots of other circuitry.

That ongoing development of the frontal cortex and the cultural amygdala in that area is some of the reason for the differing viewpoints, taboos, laws, and norms of one culture or sub-culture when compared to another culture or sub-culture  (cf. The Fruits of A Celebrity World of Illusion).

As an contrasting example of how the brain develops early, with regard to language, is presented in the video below that of Dr. Sapolsky.

That video records a recent lecture of Dr. George Lakoff.

The Dr. Lakoff video shows how the language a culture speaks has a very early influence as to how culture impacts on the shape and configuration of brain circuitry, including the physical amygdala.

Together I hope they convincingly show that culture is important to brain development, so important that we can envision a virtual entity and call it the cultural amygdala, as well as hypothesize that one's culture shapes one's cultural amygdala in meaningful ways.

Thus, how impulses etc. from the physical amygdala, which frontal cortex dynamics regulate to the extent that they can, are to a degree also influenced by the cultural amygdala, as well as, to a lesser degree, the individuality of every person.

That is another reason why the toxins of power affect those with power in many different ways, even though the raw power itself may be the same across cultures.

That is, a ruler in Culture A, a culture which is way different from Culture B, will be exposed to the same basic toxins of power that a ruler in Culture B will, however, may react to the same toxins of power differently to the extent that the cultural amygdala is different.

The next post in this series is here, the previous post in this series is here.

Video index to The Limbic System video, by Dr. Sapolsky

15:20 logical section / emotional section theory of mind is nonsense
15:40 Antonio Demasio - shows Descarte utterly wrong
16:30 circuitry (James Papes)
17:40 Papes circuitry - emotional part of brain
18:58 entire limbic system tries to influence what the hypothalamus does
21:20 stilulating / restricting sections depends on closeness to hypothalamus
23:12 our olfactory system is closest to hypothalamus
24:30 amygdala
26:35 hyocampus
27:25 septum: mid-brain area
28:58 PFC (impulse control, emotional control) develops last
34:30 amygdala / hippocamus memory - connections
50:15 amygdala gets larger in people with PTSD
50:45 stress causes amygdala neurons to grow more dendritic processes
51:00 hippocampus gets smaller @ depression
101:00 amygdala activating aggression
102:18 septum inhibits aggression
103:30 hippocamus turn off stress response
104:40 precortal / frontal moderator
113:40 James / Lang theory of emotion




Randy said...

For a culture shock, compare Camden, NJ to Geneva, Switzerland: Link

Dredd said...

An interesting adjunct is that people blind from birth have cultural visions of race (Blind People See Race).