People with damage to the amygdala do not respond to fear evoking stimuli the way a normal person would. The brain also has direct pathways to the amygdala that generate quicker responses, but less accuracy. Individuals with PTSD tend to have stronger pathways here, accounting for out of context (no cortex processing) responses.
Williams Syndrome - facility with language and emotion despite being mentally retarded. Very trustful and gregarious. Susceptible to being taken advantage of. Their amygdala basically does not respond to aggressive faces.So we have high functioning language and emotional perception with low amygdala activity.
Social phobias. Any face invokes activity in the amygdala. For depressives the amygdala becomes more active when they are shown something sad. Perhaps what the amygdala is truly tuned into is whatever is scariest to you.
Us and them. Another role for the amygdala.
The frontal cortex is responsible for getting you to do the harder thing when the harder thing is the better/right thing to do. And it has to do this through a series of weak, diffuse signals. So it's more or a slow, consistent urging. And dopamine is the fuel that helps with those urges.
Dopamine drives goal directed behavior. Dopamine isn't so much the reward in the pleasure pathway; it's what drives you to do the action in order to get the reward.
Executive function - grouping, ordering and remembering. Strategy. This is a big role for the frontal cortex. People with damage to the frontal cortex don't use cognitive strategies.
Frontal temporal dementia. Clockface and 11:10 example. Another example is reciting months backwards - can only go backwards for a short period (December-November-October-September-October). Then the next test will be counting back from 20 and you get 20-19-18-17-September. Previous tasks intrude on the current task. The frontal cortex is responsible for remembering the rules.
They have a high metabolic rate, which in turn means they are more vulnerable than other neurons. The good news is rules can eventually become implicit.
Phineas Gage, foreman on railroad construction line in Vermont. A dynamite explosion propelled a metal rod straight through his head and frontal cortex. Phineas went from responsible to wild. The simple conclusion was that the frontal cortex reins in "animal" behavior.
In the modern world, this kind of damage is seen more with individuals who have stroke damage to the frontal cortex. About 25% of inmates on death row have a history of concussive head trauma to the front of the head. This can create frontal cortical damage (hits to the front or back of the head can cause this type of damage as concussions occur when the brain gets slammed around inside the skull. The damage is often seen on the opposite side of the originating blow as that's where the brain was shoved.)
McNaughton Rule - can the individual tell the difference between right and wrong? McNaughton was a paranoid schizophrenic who attempted to kill the British Prime Minister back in 1849. The man was so over the top psychotic that the jury basically ruled that he was too far gone to be expected to be responsible for his actions as he clearly was thoroughly disconnected from reality. The giveaway is any attempt to cover one's tracks. After Hinckley was found criminally insane there was massive backlash across the US.
The catch is that there's a difference between knowing the rules and being able to follow them. For most of us this is about struggling to maintain a diet or exercise as much as we should. For others it can be the difference between following social rules and ending up committing crimes.
The timing of frontal damage impacts whether the person knows the rules. Get frontal damage before you're 5-6 years old and you don't even grasp the rules. Get damage later on and you become one of those that says "this is wrong and against the rules" and then goes and does it anyway.
However, environment impacts what type of behavior emerges. In the end the result isn't always violent.
Where the challenge comes in is what do you do with someone who has 100% of the cortex messed up? 99%? 95%? Where's the line? Is there one?
The frontal cortex is least active during REM sleep, accounting for bizarre dreams and odd thought flows.
It doesn't fully develop until the early to mid 20's. Thus it is least constrained by genes and most influenced by humans.
Dopamine fluctuations for unexpectedly good rewards and not getting an earned reward are much greater in teens than adults. Thus unexpected joys are more pleasant and unfair deprivations are more depressing.
Sadly it's vulnerable during normative aging. The substantia nigra, the hippocampus and then the frontal cortex. So we get weakness and trembling (and maybe Parkinson's), trouble with memory and learning (and maybe Alzheimer's) and endless constant complaints (and old ladies with their dentures knocked out...)
Highly regimented people have high metabolic rates in the frontal cortex. Sociopaths not so much. When tested for non emotive tasks, it takes much more effort metabolically for a sociopath to activate the frontal cortex pathways (say for the months backward task).
With chimps they simply cannot go for the 1 M&M to get 5 M&M's, but they can go for 1 chip of wood to get 5 M&M's. Thus they understand the task but the food drive is too great. Remove the food and they can do it correctly.
Studies suggest that by age 5 there are already measurable differences in the thickness and resting metabolic rates of the frontal cortex in different socioeconomic groups. Different levels of glucocorticoid action are also evident (glucocorticoids are stress hormones that, over time, degrade neurons).
Generally speaking the frontal cortex seems to have more of a role in regulating the amygdala than other brain areas. The amygdala also tries to regulate the frontal cortex.
Lateral hypothalamus - food acquisition not aggression.
Anterior cingulate. Pain, compassion pathway. Feeling the pain of the world. Josh Green of Harvard conducted experiments in which people were encouraged to imagine the following scenario - You're a Jew in hiding in Nazi Germany. A child in your group is crying loudly and is going to give you away. Is it ok to smother the child? People who activate the anterior cingulate less when making their decision are more likely to decide that it's ok to smother the child.
"Descartes Error" - the notion that emotion and thought aren't separate domains at all. The trolley test - if it's about pulling the lever the cortex is primarily activated. If it's about pushing the guy, it's the limbic system.
The human brain,the literal, and metaphors. The basic off the rack brain isn't really designed for all this fancy abstract stuff and it essentially has to use the old wiring. So we get this whole world of gut responses and moral views expressed through physiological metaphors, including the insular cortex (warm personalities, that makes me sick, it's nauseating, how disgusting). Moral transgressions and the part of the brain designed to watch out for rotten food.
Thus moral decisions are really affective decisions that we then rationalize the way we want to. But what else could they be when that's the brain's design?
Elie Wiesel - the opposite of love is not hate, it's indifference. Physiologically true - a lot about excitation. Helps explain how humans "get these confused."
Testosterone is associated with aggression but is not the cause. Behavior drives testosterone release. It amplifies but does not initiate.
Bizarre - spotted hyenas. Dominant females with male like genitalia. Among primates, males can get erections to show dominance. In spotted hyena world, males will get erections to show submission.
Williams Syndrome - facility with language and emotion despite being mentally retarded. Very trustful and gregarious. Susceptible to being taken advantage of. Their amygdala basically does not respond to aggressive faces.So we have high functioning language and emotional perception with low amygdala activity.
Social phobias. Any face invokes activity in the amygdala. For depressives the amygdala becomes more active when they are shown something sad. Perhaps what the amygdala is truly tuned into is whatever is scariest to you.
Us and them. Another role for the amygdala.
The frontal cortex is responsible for getting you to do the harder thing when the harder thing is the better/right thing to do. And it has to do this through a series of weak, diffuse signals. So it's more or a slow, consistent urging. And dopamine is the fuel that helps with those urges.
Dopamine drives goal directed behavior. Dopamine isn't so much the reward in the pleasure pathway; it's what drives you to do the action in order to get the reward.
Executive function - grouping, ordering and remembering. Strategy. This is a big role for the frontal cortex. People with damage to the frontal cortex don't use cognitive strategies.
Frontal temporal dementia. Clockface and 11:10 example. Another example is reciting months backwards - can only go backwards for a short period (December-November-October-September-October). Then the next test will be counting back from 20 and you get 20-19-18-17-September. Previous tasks intrude on the current task. The frontal cortex is responsible for remembering the rules.
They have a high metabolic rate, which in turn means they are more vulnerable than other neurons. The good news is rules can eventually become implicit.
Phineas Gage, foreman on railroad construction line in Vermont. A dynamite explosion propelled a metal rod straight through his head and frontal cortex. Phineas went from responsible to wild. The simple conclusion was that the frontal cortex reins in "animal" behavior.
In the modern world, this kind of damage is seen more with individuals who have stroke damage to the frontal cortex. About 25% of inmates on death row have a history of concussive head trauma to the front of the head. This can create frontal cortical damage (hits to the front or back of the head can cause this type of damage as concussions occur when the brain gets slammed around inside the skull. The damage is often seen on the opposite side of the originating blow as that's where the brain was shoved.)
McNaughton Rule - can the individual tell the difference between right and wrong? McNaughton was a paranoid schizophrenic who attempted to kill the British Prime Minister back in 1849. The man was so over the top psychotic that the jury basically ruled that he was too far gone to be expected to be responsible for his actions as he clearly was thoroughly disconnected from reality. The giveaway is any attempt to cover one's tracks. After Hinckley was found criminally insane there was massive backlash across the US.
The catch is that there's a difference between knowing the rules and being able to follow them. For most of us this is about struggling to maintain a diet or exercise as much as we should. For others it can be the difference between following social rules and ending up committing crimes.
The timing of frontal damage impacts whether the person knows the rules. Get frontal damage before you're 5-6 years old and you don't even grasp the rules. Get damage later on and you become one of those that says "this is wrong and against the rules" and then goes and does it anyway.
However, environment impacts what type of behavior emerges. In the end the result isn't always violent.
Where the challenge comes in is what do you do with someone who has 100% of the cortex messed up? 99%? 95%? Where's the line? Is there one?
The frontal cortex is least active during REM sleep, accounting for bizarre dreams and odd thought flows.
It doesn't fully develop until the early to mid 20's. Thus it is least constrained by genes and most influenced by humans.
Dopamine fluctuations for unexpectedly good rewards and not getting an earned reward are much greater in teens than adults. Thus unexpected joys are more pleasant and unfair deprivations are more depressing.
Sadly it's vulnerable during normative aging. The substantia nigra, the hippocampus and then the frontal cortex. So we get weakness and trembling (and maybe Parkinson's), trouble with memory and learning (and maybe Alzheimer's) and endless constant complaints (and old ladies with their dentures knocked out...)
Highly regimented people have high metabolic rates in the frontal cortex. Sociopaths not so much. When tested for non emotive tasks, it takes much more effort metabolically for a sociopath to activate the frontal cortex pathways (say for the months backward task).
With chimps they simply cannot go for the 1 M&M to get 5 M&M's, but they can go for 1 chip of wood to get 5 M&M's. Thus they understand the task but the food drive is too great. Remove the food and they can do it correctly.
Studies suggest that by age 5 there are already measurable differences in the thickness and resting metabolic rates of the frontal cortex in different socioeconomic groups. Different levels of glucocorticoid action are also evident (glucocorticoids are stress hormones that, over time, degrade neurons).
Generally speaking the frontal cortex seems to have more of a role in regulating the amygdala than other brain areas. The amygdala also tries to regulate the frontal cortex.
Lateral hypothalamus - food acquisition not aggression.
Anterior cingulate. Pain, compassion pathway. Feeling the pain of the world. Josh Green of Harvard conducted experiments in which people were encouraged to imagine the following scenario - You're a Jew in hiding in Nazi Germany. A child in your group is crying loudly and is going to give you away. Is it ok to smother the child? People who activate the anterior cingulate less when making their decision are more likely to decide that it's ok to smother the child.
"Descartes Error" - the notion that emotion and thought aren't separate domains at all. The trolley test - if it's about pulling the lever the cortex is primarily activated. If it's about pushing the guy, it's the limbic system.
The human brain,the literal, and metaphors. The basic off the rack brain isn't really designed for all this fancy abstract stuff and it essentially has to use the old wiring. So we get this whole world of gut responses and moral views expressed through physiological metaphors, including the insular cortex (warm personalities, that makes me sick, it's nauseating, how disgusting). Moral transgressions and the part of the brain designed to watch out for rotten food.
Thus moral decisions are really affective decisions that we then rationalize the way we want to. But what else could they be when that's the brain's design?
Elie Wiesel - the opposite of love is not hate, it's indifference. Physiologically true - a lot about excitation. Helps explain how humans "get these confused."
Testosterone is associated with aggression but is not the cause. Behavior drives testosterone release. It amplifies but does not initiate.
Bizarre - spotted hyenas. Dominant females with male like genitalia. Among primates, males can get erections to show dominance. In spotted hyena world, males will get erections to show submission.
