Thoughts are different than words. You may not be able to think of what you want to say but you still have the thoughts.
Aphasia
Aphasia is deficits in language comprehension and production. Broca's and Wernicke's Aphasia have been study quite a bit; Broca's Aphasia more than Wernkicke's.
Broca's Aphasia is an impairment in syntax. Syntax is important to convey they meaning of something and when you lose the meaning you lose syntax. They have difficulty in finding the words that they want. Broca believed that this was caused by cortical damage in the inferior frontal lobe, but there is more that is involved than Broca thought. By the Twenty Century researchers found that there were deficits in the insular cortex, lenticular nucleus of the basal ganglia and the fibers of passage.
Wernicke's Area includes the poterior third of the superior temporal gyrus. Evidence has shown that you can have Wernicke's Aphasia even without damage to the areas that are believed to be a part of the Wernicke's Area.
Semantic versus Syntactic Processing
Semantic = N400, which processes meaning and the Syntactic = P600 focuses on the appearance. They had subjects read sentences and their EEGs were averaged over time. WIth a word that does not fit in the sentence (anomalous word) there was a negative deflection in the N400 and with the word that was larger than the rest of the words there was a positive wave in the P600. the Semantic effect came before the syntactic effect. Research has shown that any words that are surprising in meaning get a wave.
Wednesday, November 10, 2010
Chapter 9: Emotion
Urbach-Wiethe Disease
Urbach-Wiethe disease is an impairment in perceiving others' emotions. SM had bilateral damage to the amygdala. His intelligence scores were normal but he was not able to understand fear.
Basic Emotions and the Dimensions
There are six basic human facial expressions: anger, fear, disgust, happiness, sadness and surprise. There are two basic dimensions for emotions. Valence, which distinguishes between pleasant and unpleasant emotions and arousal, which is how intense the emotional response is. Richard Davidson has two other items: withdraw and approach. Approach is the idea that stimulus that is either happy or surprising leads us to approach the situation, but fear and disgust leads us withdraw from the situation. Typically, withdraw goes hand-in-hand with negative valence.
Limbic System
James Papez come up with the circuit theory of brain and emotion. It says that emotional responses involve a network of brain regions. Including the hypothalamus, anterior thalamus, cingulate gyrus and the hippocampus. However, there is not much evidence that shows the hippocampus plays a role in emotion.
Amygdala
Heinrich Kluver and Paul Bucy damaged the amygdala in monkeys and observed the deficit called psychic blindness. They found that they tended to approach items that would usually elicit a fear response. However, the lesions may have been sloppy; they probably damaged the surrounding areas of the amygdala as well as the amygdala itself.
Others have done studied fear conditioning in rats. Before training a light was shown and the rats showed no response; however, with the foot shock and loud noise they did show a response. During the training the paired the light and shock, which elicited a fear response. Eventually the light alone would produce the same response. When the light and sound were paired it also produced a fear response, this is called the potentiated CR. They learned response was impaired when the amygdala is damaged.
SP had bilateral damage to the amygdala. SP was unable to recognize fear in faces. During the learning phase they were just shown a picture of a blue square. During the acquisition phase, they were given a shock to the rest and the end of the presentation of the blue square. They had a normal response when the shock was presented but there was no change when the blue square was shown. SP has declarative knowledge but no behavioral response. Patients with bilateral damage to the hippocampus and not the amygdala produce a normal behavioral response but they cannot explain why they responded that way.
Social Response (facial expressions and social grouping)
When presented a picture of a face with a fearful expression, the amygdala will increase in response. The deficit is only with the recognition of facial expressions because they are able to generate and communicate their own facial expressions. The reason SM may not be able to recognize fear is because fear is mostly shown in the eyes. Other emotions are shown in other parts of the face. SM did not focus on the eyes, instead they looked at other parts of the face.
Behavioral research examines behavioral responses that demonstrate preference for one group over another. Bias is calculated by the difference in the response latency between the black + good/white +bad trials versus the black + bad/white + good trials. Elizabeth Phelps used an MRI to see activation in white subjects when viewing black and white faces. When these subjects saw a picture of an unfamiliar black face the amygdala was activated.
Urbach-Wiethe disease is an impairment in perceiving others' emotions. SM had bilateral damage to the amygdala. His intelligence scores were normal but he was not able to understand fear.
Basic Emotions and the Dimensions
There are six basic human facial expressions: anger, fear, disgust, happiness, sadness and surprise. There are two basic dimensions for emotions. Valence, which distinguishes between pleasant and unpleasant emotions and arousal, which is how intense the emotional response is. Richard Davidson has two other items: withdraw and approach. Approach is the idea that stimulus that is either happy or surprising leads us to approach the situation, but fear and disgust leads us withdraw from the situation. Typically, withdraw goes hand-in-hand with negative valence.
Limbic System
James Papez come up with the circuit theory of brain and emotion. It says that emotional responses involve a network of brain regions. Including the hypothalamus, anterior thalamus, cingulate gyrus and the hippocampus. However, there is not much evidence that shows the hippocampus plays a role in emotion.
Amygdala
Heinrich Kluver and Paul Bucy damaged the amygdala in monkeys and observed the deficit called psychic blindness. They found that they tended to approach items that would usually elicit a fear response. However, the lesions may have been sloppy; they probably damaged the surrounding areas of the amygdala as well as the amygdala itself.
Others have done studied fear conditioning in rats. Before training a light was shown and the rats showed no response; however, with the foot shock and loud noise they did show a response. During the training the paired the light and shock, which elicited a fear response. Eventually the light alone would produce the same response. When the light and sound were paired it also produced a fear response, this is called the potentiated CR. They learned response was impaired when the amygdala is damaged.
SP had bilateral damage to the amygdala. SP was unable to recognize fear in faces. During the learning phase they were just shown a picture of a blue square. During the acquisition phase, they were given a shock to the rest and the end of the presentation of the blue square. They had a normal response when the shock was presented but there was no change when the blue square was shown. SP has declarative knowledge but no behavioral response. Patients with bilateral damage to the hippocampus and not the amygdala produce a normal behavioral response but they cannot explain why they responded that way.
Social Response (facial expressions and social grouping)
When presented a picture of a face with a fearful expression, the amygdala will increase in response. The deficit is only with the recognition of facial expressions because they are able to generate and communicate their own facial expressions. The reason SM may not be able to recognize fear is because fear is mostly shown in the eyes. Other emotions are shown in other parts of the face. SM did not focus on the eyes, instead they looked at other parts of the face.
Behavioral research examines behavioral responses that demonstrate preference for one group over another. Bias is calculated by the difference in the response latency between the black + good/white +bad trials versus the black + bad/white + good trials. Elizabeth Phelps used an MRI to see activation in white subjects when viewing black and white faces. When these subjects saw a picture of an unfamiliar black face the amygdala was activated.
Chapter 8: Learning and Memory
Learning is the process of acquiring new information and the outcome is memory. There are three stages of learning: (1) Encoding: process the information. There are two steps to encoding acquisition, which registers the inputs and consolidation, which strengthens the representation of the information. (2) Storage: record the information. (3) Retrieval
Short-term Memory
STM is dissociable from LTM. STM turns into LTM eventually. GE had a tumor in the left angular gyrus, affecting the inferior parietal cortex and posterior superior temporal cortex. He had deficits in STm but no in LTM.
Working Memory
Baddeley and Hitch said that there are three components for working memory. The central executive controls the phonological loop, which deals with what we hear and the visuospatial sketch pad deals with what we see. Different lesions of the brain produce different deficits in the process. Lesions to the left supramarginal gyrus produces deficits in the phonological loop. Lesions to the parieto-occipital region (mostly in the right hemisphere than the left) produces deficits in the visuospatial sketch pad.
Long-term Memory
There are two parts of LTM - declarative and nondeclarative memory. Declarative memory is our conscious memory and it plays a big role in our social interchange. It looks as if the medial temporal lobe is important to declarative memory. Declarative memory can be broken down into two different parts; episodic (events in our lives) and semantic (world knowledge) memory. Nondeclarative can be broken down to two different parts: procedural memory and perceptual representation system. Procedural memory is learning motor and cognitive skills. Perceptual representation system is the idea that the structure and form of an object or words can be primed by prior experience.
Memory and the Brain
RB had lesions in the hippocampus, more specifically the CA1 pyramidal cells. It seems as if the hippocampus is important when forming LTM. Korsakoff's Syndrome is associated with alcoholism. It causes a thiamine deficiency which leads to the degeneration of the diencephalon, especially the dorso medial nucleus of the thalamus and mammilary bodies.
Consolidation
Consolidation is the solidification of memories to LTM. Evidence from patients who have done ECT shows that memories must be consolidated. THey found that retrograde amnesia is more likely to affect items that were learned close to the time of the ECT. Semantic information is consolidated in the temporal neocortex.
Learning New Declarative Information
KC had a loss of episodic memory but his semantic memory was intact. Semantic memories are established because of episodic memories. KC had damage to the medial temporal lobe, left dorsolateral prefrontal cortex, premotor cortex and the parietal and occipital cortices. This produced severe anterograde and retrograde amnesia.
Beth, Jon and Kate (all siblings) had hippocampal damage. They could learn semantic information but they did not know where it came from, which is called source amnesia.
Learning New Nondeclarative Information
HM can learn new things but he could not say how he know the task. He was asked to do a mirror task and he got better every time he had to carry out the task. So his procedural memory is intact but his declarative memory is lost.
Mortimer Mishkin (1978)
He removed the hippocampus, amygdala or both in monkeys. The monkeys were tested in the delayed nonmatch-to-sample task. The card is placed over the reward (food) then the door is opened. The monkey has to pick where the reward is in order to get the food. The door is closed again and a new object is introduced. The novel card is placed over the reward and after a delay the door is reopened. The monkey has to pick the novel card in order to get the reward. After training, the monkey is able to pick the new item to get the reward. If the hippocampus and the amygdala is damaged memory was impaired.
Short-term Memory
STM is dissociable from LTM. STM turns into LTM eventually. GE had a tumor in the left angular gyrus, affecting the inferior parietal cortex and posterior superior temporal cortex. He had deficits in STm but no in LTM.
Working Memory
Baddeley and Hitch said that there are three components for working memory. The central executive controls the phonological loop, which deals with what we hear and the visuospatial sketch pad deals with what we see. Different lesions of the brain produce different deficits in the process. Lesions to the left supramarginal gyrus produces deficits in the phonological loop. Lesions to the parieto-occipital region (mostly in the right hemisphere than the left) produces deficits in the visuospatial sketch pad.
Long-term Memory
There are two parts of LTM - declarative and nondeclarative memory. Declarative memory is our conscious memory and it plays a big role in our social interchange. It looks as if the medial temporal lobe is important to declarative memory. Declarative memory can be broken down into two different parts; episodic (events in our lives) and semantic (world knowledge) memory. Nondeclarative can be broken down to two different parts: procedural memory and perceptual representation system. Procedural memory is learning motor and cognitive skills. Perceptual representation system is the idea that the structure and form of an object or words can be primed by prior experience.
Memory and the Brain
RB had lesions in the hippocampus, more specifically the CA1 pyramidal cells. It seems as if the hippocampus is important when forming LTM. Korsakoff's Syndrome is associated with alcoholism. It causes a thiamine deficiency which leads to the degeneration of the diencephalon, especially the dorso medial nucleus of the thalamus and mammilary bodies.
Consolidation
Consolidation is the solidification of memories to LTM. Evidence from patients who have done ECT shows that memories must be consolidated. THey found that retrograde amnesia is more likely to affect items that were learned close to the time of the ECT. Semantic information is consolidated in the temporal neocortex.
Learning New Declarative Information
KC had a loss of episodic memory but his semantic memory was intact. Semantic memories are established because of episodic memories. KC had damage to the medial temporal lobe, left dorsolateral prefrontal cortex, premotor cortex and the parietal and occipital cortices. This produced severe anterograde and retrograde amnesia.
Beth, Jon and Kate (all siblings) had hippocampal damage. They could learn semantic information but they did not know where it came from, which is called source amnesia.
Learning New Nondeclarative Information
HM can learn new things but he could not say how he know the task. He was asked to do a mirror task and he got better every time he had to carry out the task. So his procedural memory is intact but his declarative memory is lost.
Mortimer Mishkin (1978)
He removed the hippocampus, amygdala or both in monkeys. The monkeys were tested in the delayed nonmatch-to-sample task. The card is placed over the reward (food) then the door is opened. The monkey has to pick where the reward is in order to get the food. The door is closed again and a new object is introduced. The novel card is placed over the reward and after a delay the door is reopened. The monkey has to pick the novel card in order to get the reward. After training, the monkey is able to pick the new item to get the reward. If the hippocampus and the amygdala is damaged memory was impaired.
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