More Limbic Cat Brain

Fish evolved in the sea 500million years ago

Mammal-like reptiles evolved 300million years ago

250 million years ago was the Permian extinction in which most species died

200 million years ago came the first mammals

120 million years ago the early mammals quit laying eggs

Reptiles ruled the earth during the day.  They evolved into massive dinosaurs, while the first mammals of 200 million years ago were tiny nocturnal warm blooded creatures, which lived underground.   In order to survive, early mammals learned to  live in groups.  Brains that were good at living with others were more likely to reproduce.  Unlike reptiles, which evolved gained superiority as they became physically larger, mammals thrived by increasing their biomass through accumulation of allies that could cooperate.  Mammals have hair, are warm-blooded, have middle ear bones, a limbic system and raise their young.  Our ability to learn has roots in our relationships. We have feelings.

The limbic system contains the brain structures of emotional intelligence and every mammal has one.  Also called the rhinencephalon, or nose brain, it regulates  our bodies function through the autonomic nervous system and hypothalamus and makes up 40% of the rodent brain.  Smell directs rodent emotion.  Our olfactory portion is only 5% of our brain.    A main difference between the human and chimpanzee brain is we have 1000 fewer olfactory genes.  The neurons in your pituitary and hypothalamus evolved from cells designed to help our ancestors sense a potential mate thus the purpose of the limbic system is to influence the hypothalamus in the spread of our genes.   To the egg a chicken is just a device to create another egg. We also spread our genes when our close relatives procreate since we share genes.

Mammals evolved after reptiles but before primates.   Our limbic system mediates social emotions such as separation, distress, social bonding, playfulness, and maternal nurturance.   A mammal can react positively to another mammal.   Neurochemicals include neurotransmitters, which stay in the brain and hormones, which are released into the bloodstream.   These work together in our pursuit of happiness and status.  The brain releases happy chemicals in response to improved survival prospects.  As soon as a mammal meets is immediate survival needs it puts is efforts into raising its status.  Survival and status are the same since status improves the chance of having surviving descendants. There is a pecking order among beasts with tails and it has been found that animals and humans lower in the pecking order have higher cortisol levels.  This negatively impacts both their prefrontal cortex, which controls executive functioning and immune system impacting general health.  From the stress of poverty glucocorticoids are known to atrophy the frontal cortex and lower is level of activity.   Sapolsky notes that “when humans invented poverty they came up with a way of subjugating the low ranking like nothing seen in the primate world.” 

The prefrontal cortex is the cortical area intertwined with the limbic system.  Its size in a species correlates with how large the average social group of the species is.   When there is a choice between something harder that is better in the long run and something easier it gets you to do the harder thing.  It promotes impulse control, planning and is the last part of the brain to mature.  It is not fully myelinated in humans until age 25 and it provides emotional regulation for long term planning, gratification, impulse control, and postponement.  It evolved for gossip, social relations and emotional intelligence. It is what makes us human.  The role of the prefrontal cortex was learned about by what happened to Phineas Gage. 

The Marshmallow test if given to 5 year olds can predict their SAT scores.   You offer Marshmallow now or if they can wait they can have two and the kids who have a more developed prefrontal cortex choose to wait.  There is also a Hide and seek test.  If you play hide and seek with 5 year old they often cant resist telling you where they are and when they count they go on past ten

Humans create hierarchies just like other primates.  When you improve your status in the hierarchy the brain releases a short burst of the same happy chemicals that it rewards reproductive success.  Dopamine gives the frontal cortex the energy to push you to do the right thing. When you loose status the brain releases unhappy chemicals.  Humans usually belong to several ranking systems at the same time and rank economically, intellectually, socially etc. 

We are wired for hierarchy.  When women are at college their periods synchronize to the period of the socially dominant female that is the most attractive or social. 

There are 3 areas of the brain that tend to wear out with age.   When he Substantia nigra goes it causes a tremor and Parkinson’s.  With damage to the hippocampus memory is impaired, and as frontal cortex looses neurons we see diminished tests of cognitive function and disinhibited 80 year olds.   People know what they should do but can’t choose the correct thing.  One looses the ability to plan for the future due to the brain damage of age.  This may be why people become conservative as they age.  People who are disciplined have higher metabolic rates in their prefrontal cortex. People who had lower prefrontal activity can be sociopaths. 

Pre Frontal cortex inhibits the amygdala and The amygdala tries to inhibit the frontal cortex.  When you are under stress the amygdala silences the frontal cortex and you get unregulated behavior.   Without a pre frontal cortex the amygdala doesn’t adjust to new situations.   If the harder thing is the scarier thing the frontal cortex can in that situation stimulate the amygdala. 

When you walk in a room the first thing you do is scan the room to see if there is anything that can eat you.  If there is, the eye sends a message to the amygdala, which tells the hypothalamus to release stress hormones (cortisol) and the sympathetic nervous system to release adrenalin.  If there are no threats we look to see is there anything we can eat.  Digestion involves the parasympathetic nervous system.  Then we see is there anything we can mate with and anything that will mate with us.  In rodents this occurs through the nose.  Smell governs rodent emotions.   Incidentally for us 90% of taste is smell.  The olfactory neurons are one synapse away from the limbic system in both rodents and us and thus our noses motivate us.  Thus the limbic system drive the 4 Fs .

There are 7 separate emotion systems in the brain

seeking  -  anticipation

rage  -  frustration

fear  -  pain threat

panic   - loss

play  -  carefree

mating -  copulation who and when

care -   maternal nurturance

each of these has its own specific area in the brain

The limbic system is also involved with memory and includes the hippocampus.  We remember things best, which are emotionally charged, and this was important for survival.  When the brain detects an emotionally charged event the amygdala releases dopamine, which tells the hippocampus to file this.  We remember how to escape from the tiger

Relatedness biases us toward cooperation.  Pseudo-relatedness (the formation of artificial groups) can also do this.   We tend to organize in groups.  Sapolsky tells how in the filming of the movie Planet of the Apes the actors playing the Apes all ate together separately from the actors playing humans.  Playing repeated rounds also promotes cooperation and we are given the opportunity to reciprocate.  It has been learned that we have in the amygdala mirror neurons, which get excited if we and someone else are moving in synchrony.   Another part of the limbic system the anterior-cingulate has to do with empathy and moral affective decision-making.  Since people related to us carry our genes helping relatives is a way of spreading genes,

 

An early experience for children is learning when to be aggressive.   How does morality  develop in kids.  At first kids can distinguish between inanimate and animate within the first few weeks of life .  Normal kids respond to faces while Autistic kids don’t do this.  Kids differentiate themselves from the world around them.  First they view themselves as continuous with their environment, which is mom. Kid says I have an owie if mom has a cut.    Then they become aware of others and develop a theory of mind.    This starts at ages 3 – 5  and is this a prerequisite for empathy.  Sociopaths have theory of mind  but they don’t have empathy.  Through theory of mind we can gain social awareness by seeing the world through the motivations of others

Lawrence Kohlberg listed the  stages of moral development as a  sequence of developments including:

Preconventional  - you may get caught  or a reward

Conventional -  your motivation based on shared group values  rules laws postconvention moral reasoning – there are things that are more important  bad laws need to be broken  this is the right thing to do

Not every gets to the postconventional stage

Moral development questions include:

How do kids learn that it is ok to lie?

What are Rules and principles?

How do kids learn there are bad laws?

What are Intended harm and successful harm?

What are the effects of growing up in a violent setting?  Greater child abuse and greater antisocial behavior

Parents are good for determining what peer groups kids have access to.  Kids learn more from their peers.  Emigrant kids pick up the accents of peers over their parents.

If you break kids into groups they have disparaging beliefs about other groups. 

Implicit knowledge is located in the cerebellum. 

Studies show moral actions are implicit.  If you have to think about whether to cheat, then you will cheat some of the time.  The people who don’t cheat do it implicitly