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LECTURE_14_SLIDES - NPB12 Lecture 14 Grizabella the Glamour...

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Unformatted text preview: NPB12 Lecture 14 Grizabella the Glamour Cat Memory All alone in the moonlight I can smile at the old days I was beautiful then I remember the time I knew what happiness was Let the memory live again Memories, Like the corners of my mind Misty water-colored memories Of the way we were Scattered pictures, Of the smiles we left behind Smiles we gave to one another For the way we were Thanks for the memory Of letters I destroyed Books that we enjoyed Tonight the way things look I need a book by Sigmund Freud How brainy he was Procedural Memory T his is the memory where you get better at something but donʼt really know why are can describe exactly what you are doing. Echoic Memory Let s you remember the first part of a long sentence so that by the time it takes to get to the end of the sentence you haven t forgotten what the sentence was initially trying to tell you. T his is the very short term memory that allows you to put together things like words, phrases and sentences. Declarative Memory: 2 Stages longer than echoic memory but doesnt stick Short-term memory phone numbers names of people you just met Long-term memory locker combination going to Disneyland Memory Deficits: Amnesias 2 types: Retrograde: You can t remember anything that happened before the event. Anterograde: You can t remember anything that happened after the event. EVENT Birth Retrograde Amnesia Anterograde Amnesia Anterograde amnesia is defined as the inability to remember events that occur after the reason that the amnesia exists time Present Cerebral Cortex and the Limbic System: Circuitry? Entorhinal cortex Concussion: A transient arrest of brain activity due to a blow to the head or sudden acceleration and deceleration of the skull ("whiplash") without detectable pathological change. Severity is measured by the extent of anterograde amnesia Concussions can cause both retrograde and anterograde amnesia, but usually the retrograde amnesia is only for a few minutes before the blow. The severity of the concussion can be fairly well characterized by the length of the anterograde amnesia. Regular people Athletes Ben Rothlisberger Korsakoff s Psychosis Symptoms: anterograde amnesia retrograde amnesia apathy decreased spontaneity confabulation Normally seen in alcoholics and results from a vitamin B1 deficiency Primarily affects the mammillary bodies Transient Global Amnesia (TIA) Defined as a sudden but transient retrograde and anterograde amnesia. Duration is usually only a few hours Patient is unable to remember anything about the immediately preceding events, including how they got where they now are. Blood flow to the brain (particularly the hippocampus) is compromised, so it stops working. Instead of the cells actually dying, they are just not working right and then you get better. Herpes-Simplex Encephalitis Virus enters via the nose or mouth Manages to somehow get into the central nervous system, and primarily affects the temporal lobes Anterograde amnesia, some retrograde amnesia, confusion and dementia. Most people get better but never remember what happened while they were sick. Agnosias A sudden inability to be able to remember certain things or how to do certain things These are usually due to a relatively small stroke in the cerebral cortex. Examples include: Prosopagnosia (inability to recall faces: fusiform face area) Agnosias: These are sometimes considered part of a memory dysfunction, and other times as a sensory, or perceptual dysfunction. T he major symptoms are the inability to recognize certain things, such as faces (prosopagnosia) parts of your own body (autotopagnosia) or how to do particular motor movements (eating, dressing, etc.) even though the ability to perform those movements are intact (apraxia). T hese conditions are predominately caused by lesions of the cerebral cortex, invariably due to strokes over restricted areas. Alzheimer s Disease Dr. Alois Alzheimer 4.5 million Americans have it T here is atrophy of the cerebral cortex and limbic structures with neuronal loss, senile plaques (also called neuritic plaques) throughout the cerebral cortex, and neurofibrillary tangles found throughout the cerebral cortex and hippocampus. Hallmark symptom is memory loss followed by dementia Memory loss is different from senile dementia Symptoms progress to lack of mobility, muteness, etc. spastic/rigid paralysis. neonatal reflexes return coma, respiratory arrest, death Neurons in the cerebral cortex die. Initial losses are in the memory and language areas, but eventually much of the cerebral cortex is affected. neurofibrillary tangles senile plaques T here is atrophy of the cerebral cortex and limbic structures with neuronal loss, senile plaques (also called neuritic plaques) throughout the cerebral cortex, and neurofibrillary tangles found throughout the cerebral cortex and hippocampus. How do you get it? Is it normal aging? genetics? environmental toxins? stress? trace elements? Role of Acetylcholine? Recently it has become increasingly clear that there is a decrease in the acetylcholine circuits of the brains of Alzheimer's patients as well. In the peripheral nervous system, acetylcholine opens a channel that allows ions to pass through the membrane, and is thus a fast synaptic transmitter. In the cerebral cortex there is a second type of acetylcholine receptor that activates a G-protein causing a chemical cascade and change in the amount of a second messenger, similar to what we have already seen for dopamine and photoreceptors. This has led to the hypothesis that perhaps the acetylcholine structures are the original problem, giving rise to the other symptoms. Unfortunately, using acetylcholine-mimicking drugs does not seem to help these patients for any length of time, opposite of the L-Dopa treatments for Parkinson's patients. It is in the public mind, there is more money being spent on research on this disease than other memory diseases, but no cure in sight. Epilepsy surgery for H.M. Medically intractable epilepsy Surgery to remove the epileptic focus Entorhinal cortex on both sides Hippocampus on both sides Amygdala on both sides Previous patients that had these things removed on one side had no bad side effects. H.M. was different Result: Complete loss of declarative memory. Small retrograde and complete anterograde amnesia. Lost in the present Procedural memory is fine Factual knowledge is hard, but he can remember facts. This is semantic memory. Brenda Milner But he can t remember events that happened to him at all. This is eposodic memory (as in remembering episodes). Patient R.M. had only a hippocampus lesion and has the same symptoms. Kluver-Bucy syndrome Loss of normal fear Lack of ability to gauge trustworthiness Declarative Memory: Storage and retrieval Neuroscience Valet service Hippocampus: Needed to store memories Gives you the ticket and takes the coat Cerebral cortex: Needed to store memories The closet where the coat is kept Thalamus and Mammillary bodies: Needed to retrieve the memories Take the ticket from the customer and get the coat Amygdala: Make sure you remember the important stuff Treat the customer that just tipped you $20 very well so that they might tip you again James McGaugh U.C. Irvine space shuttle Columbia September 11th assassination of JFK Run rats in the maze. 30 minutes later give them either a shot of adrenaline or a shot of saline. The adrenaline should mimic what happens when you get scared. Wait different amounts of time and see how well the rats remember how to run the maze saline Time to cheese adrenaline 1 10 days after shot 20 Many experiments later, you find that stimulation of the amygdala is just as good as giving the adrenalin. The adrenaline actually works by stimulating the amygdala, which causes you to better remember where you were right before some event occurred that is important to you. What could retrograde remembering be good for? Learning: Procedural memory Classical Conditioning and Operant Conditioning Classical Conditioning Unconditioned Stimulus Food Unconditioned Response Salivate Bell: Nothing Ivan Pavlov Classical conditioning: this type of learning was made famous by Pavlov and his dogs. T he bell is the conditioned stimulus (CS), as the pairing of the bell with the food caused the unconditioned response, which is now called the conditioned response. Pair the Bell with the food several dozen times Conditioned Stimulus Bell Conditioned Response Salivate pair tone with shock until you get the conditioned response This works at the neuronal level as well. pre-conditioning # action potentials 1 2 3 4 5 6 Frequency Acetylcholine is necessary! 7 8 9 Operant Conditioning: Perform a task, make a discrimination, whatever, and get either: Positive reinforcement: (a treat) Negative reinforcement: (a punishment) This generally involved cortical plasticity as discussed before. Primary Motor Cortex Primary Somatosensory Cortex Primary Auditory Cortex Primary Visual Cortex Musicians Controls Foot Foot Leg Leg Body Body Arm Arm Hand Hand Face Face 5432 1 Right Hand Musicians Controls Foot Foot Leg Leg Body Body Arm Arm Hand Hand Face Face 2345 1 Left Hand Pre Training Sequence 1 Pre Training Sequence 2 5 3 5 3 4 2 4 5432 2 5432 1 1 çF -ıt ßÇ{õfl˘) V6efŒˇ¶Ñ´5©iö«v ï‘S˚0Ï¡ù"íNÈ”†"T¶Ö ! ! Q#›w 6f[/ %!ÑïplÑ” éº÷| Ö ! Number of Errors Number of Cycles Training Improves Performance Training Session Training Session Trained Sequence Untrained Sequence Response to Trained Sequence Response to Untrained Sequence 5 3 5 3 4 2 4 5432 2 5432 1 1 Increased Response Area in Motor Cortex Trained Sequence 80 Untrained Sequence 60 # Pixels Activated 40 20 0 1 2 3 4 Subject 5 6 ...
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