Drug users in the late 70's made a drug called MPTP to get high. They thought it was safe because when injected into rats they saw no side-effects. Once injected into humans, however, it essentially kills all the dopamine neurons in the brain, causing Parkinson's disease. Little did they know that rats are tolerant to this drug. Now, researchers use this drug to simulate Parkinson's disease in search for a cure. There are a few treatments for Parkinson's, one of the most common is the drug L-DOPA, however, since L-DOPA requires dopamine neurons to synthesize L-DOPA into dopamine, when the patient looses most of their dopamine neurons they must look for alternatives. One alternative is surgery to remove the Globus Pallidus, a brain structure that when removed no longer inhibits the thalamus from exciting the motor cortex. Another alternative is "deep brain stimulation," which disrupts the indirect pathway and leads to more cortical excitation (more movement). Patients basically get a "pace-maker" for their brain, which can be adjusted, and even turned off.
A rat could be trained to press a lever that in turn stimulated the "pleasure" portion of the brain. The rats died from exhaustion however, because instead of eating, resting, etc, they kept hitting the lever. Similar things have happened to humans in casinos via slot machines or at home playing video games, people have literally died from exhaustion. The neurons themselves "learn" to predict rewards, but they don't ecode the stimulus, they learn if the stimulus is good or bad. The orbitofrontal cortex is responsible for encoding the "nature" of the reward - even abstract rewards like money.
We have automatic reflexes that contract muscles, increase the heart rate, blood pressure and breathing when we are startled, however, these reflexes become exaggerated when we experience the
emotion of fear. There's a famous saying that goes, "we do not run from a bear because we are afraid, rather we are afraid because we run from the bear." This is the James-Lange theory of emotion, where our emotional state is based upon our physical state. However, the Cannon-Bard theory of emotion suggests that emotions and bodily responses are not separate, but simultaneous. Evidence for the latter theory shows that paraplegics, quadriplegics, those that do not experience bodily responses, still have emotional responses, suggesting that emotions can exist without physical responses. However, the higher a spinal cord injury is the more emotional responses were indeed affected. Automatic, bodily reactions are much quicker than emotional reactions, and different emotions also have different patterns of bodily responses. The mind's attempt to explain ambiguous bodily reactions can sometimes affect the validity of what is actually happening to them. The more modern theory of emotion, is that perception/interpretation of events effects bodily changes and emotions, which in turn counter-effects perception, in a sort of emotional loop.
There are six basic emotions: anger, sadness, happiness, disgust, surprise, and fear. Emotions are processed laterally by the brain, the right hemisphere being more dominant than the left, this in turn makes the left side our our face more expressive than the right. In one side of the brain, we tend to "simulate" (or think about) the emotion we see in others to determine what they are feeling. When this part of the brain is damaged, the participant was unable to understand facial expressions and emotional cues of others. We have two sets of facial muscles, one which can be activated voluntarily, and one of which can only be activated when we are genuinely experiencing an emotion. An example of this, is shown in patients with damage to primary motor cortex which paralyzes one side of the face. When producing a "fake" smile, patients can only move the unparalyzed side of their face. However, when the smile is genuine, both sides respond. The opposite can occur as well, when damage is to the orbitofrontal cortex (emotional areas), the patient can produce a "fake" smile, but cannot genuinely smile. Emotional vs. volitional facial paresis. Those trained in "microexpressions" can determine, with about 80% accuracy, when people are lying or not.
The limbic system does most of the emotional processing. Part of this system, the amygdala, control angers responses. When the amydala wasn't functional in monkeys, the animal became very tame (no fear), hyper sexual (mounted objects) and hyperoral. This suggest that the amyddala helps to regulate the emotional significance of objects. The amygdala receives sensory information and links it to emotional information, then projects to other brain areas that control the emotional response and behavior. One of the brain areas heavily linked with the amygdala is the orbitofrontal cortex. When damaged, patients become childish, immature, and prone to violence. Psychopaths have shown a 11% reduction in volume in this area. In this brain area, if serotonin levels are low, risky and aggressiveness behavior are more prevalent when compared to brains that have high serotonin levels. Low levels are found in criminals convicted of violent crimes, children who torture animals, and soldiers expelled for excessive violence. When viewing the emotion of "disgust," humans activate the same brain region responsible for taste processing.
An alternative response to "fight or flight" is "tend or befriend" and speaks about the human tendency to come together in times of needs. High stress can affect physical growth and even lead to dwarfism. 12% of women and 7% of men have depression. There is a 20% lifetime risk for women. The late 20's is the most common onset age. Stress and depression go together. Individuals differ in their perception of what constitutes a stressor. Rats had better responses to stress when they were given an "outlet" for frustration. If we perceive ourselves to be prone to stress, then we will be.
Drug users in the late 70's made a drug called MPTP to get high. They thought it was safe because when injected into rats they saw no side-effects. Once injected into humans, however, it essentially kills all the dopamine neurons in the brain, causing Parkinson's disease. Little did they know that rats are tolerant to this drug. Now, researchers use this drug to simulate Parkinson's disease in search for a cure. There are a few treatments for Parkinson's, one of the most common is the drug L-DOPA, however, since L-DOPA requires dopamine neurons to synthesize L-DOPA into dopamine, when the patient looses most of their dopamine neurons they must look for alternatives. One alternative is surgery to remove the Globus Pallidus, a brain structure that when removed no longer inhibits the thalamus from exciting the motor cortex. Another alternative is "deep brain stimulation," which disrupts the indirect pathway and leads to more cortical excitation (more movement). Patients basically get a "pace-maker" for their brain, which can be adjusted, and even turned off.
A rat could be trained to press a lever that in turn stimulated the "pleasure" portion of the brain. The rats died from exhaustion however, because instead of eating, resting, etc, they kept hitting the lever. Similar things have happened to humans in casinos via slot machines or at home playing video games, people have literally died from exhaustion. The neurons themselves "learn" to predict rewards, but they don't ecode the stimulus, they learn if the stimulus is good or bad. The orbitofrontal cortex is responsible for encoding the "nature" of the reward - even abstract rewards like money.
We have automatic reflexes that contract muscles, increase the heart rate, blood pressure and breathing when we are startled, however, these reflexes become exaggerated when we experience the emotion of fear. There's a famous saying that goes, "we do not run from a bear because we are afraid, rather we are afraid because we run from the bear." This is the James-Lange theory of emotion, where our emotional state is based upon our physical state. However, the Cannon-Bard theory of emotion suggests that emotions and bodily responses are not separate, but simultaneous. Evidence for the latter theory shows that paraplegics, quadriplegics, those that do not experience bodily responses, still have emotional responses, suggesting that emotions can exist without physical responses. However, the higher a spinal cord injury is the more emotional responses were indeed affected. Automatic, bodily reactions are much quicker than emotional reactions, and different emotions also have different patterns of bodily responses. The mind's attempt to explain ambiguous bodily reactions can sometimes affect the validity of what is actually happening to them. The more modern theory of emotion, is that perception/interpretation of events effects bodily changes and emotions, which in turn counter-effects perception, in a sort of emotional loop.
There are six basic emotions: anger, sadness, happiness, disgust, surprise, and fear. Emotions are processed laterally by the brain, the right hemisphere being more dominant than the left, this in turn makes the left side our our face more expressive than the right. In one side of the brain, we tend to "simulate" (or think about) the emotion we see in others to determine what they are feeling. When this part of the brain is damaged, the participant was unable to understand facial expressions and emotional cues of others. We have two sets of facial muscles, one which can be activated voluntarily, and one of which can only be activated when we are genuinely experiencing an emotion. An example of this, is shown in patients with damage to primary motor cortex which paralyzes one side of the face. When producing a "fake" smile, patients can only move the unparalyzed side of their face. However, when the smile is genuine, both sides respond. The opposite can occur as well, when damage is to the orbitofrontal cortex (emotional areas), the patient can produce a "fake" smile, but cannot genuinely smile. Emotional vs. volitional facial paresis. Those trained in "microexpressions" can determine, with about 80% accuracy, when people are lying or not.
The limbic system does most of the emotional processing. Part of this system, the amygdala, control angers responses. When the amydala wasn't functional in monkeys, the animal became very tame (no fear), hyper sexual (mounted objects) and hyperoral. This suggest that the amyddala helps to regulate the emotional significance of objects. The amygdala receives sensory information and links it to emotional information, then projects to other brain areas that control the emotional response and behavior. One of the brain areas heavily linked with the amygdala is the orbitofrontal cortex. When damaged, patients become childish, immature, and prone to violence. Psychopaths have shown a 11% reduction in volume in this area. In this brain area, if serotonin levels are low, risky and aggressiveness behavior are more prevalent when compared to brains that have high serotonin levels. Low levels are found in criminals convicted of violent crimes, children who torture animals, and soldiers expelled for excessive violence. When viewing the emotion of "disgust," humans activate the same brain region responsible for taste processing.
An alternative response to "fight or flight" is "tend or befriend" and speaks about the human tendency to come together in times of needs. High stress can affect physical growth and even lead to dwarfism. 12% of women and 7% of men have depression. There is a 20% lifetime risk for women. The late 20's is the most common onset age. Stress and depression go together. Individuals differ in their perception of what constitutes a stressor. Rats had better responses to stress when they were given an "outlet" for frustration. If we perceive ourselves to be prone to stress, then we will be.
Comments
Post a Comment