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44 Cards in this Set
- Front
- Back
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What are the two memory types and explain their function?
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1. Declarative memory: available in consciousness, can be expressed in language (words, songs, images), and requires the hippocampus/medial temporal lobe
2. Non-declarative: procedural memory eg. riding a bike, not readily available in consciousness, and does not require the hippocampus or the medial temporal lobe |
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how are non declarative and declarative memory different?
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Declarative in general is something you can describe happening. Non declarative is things that you train; associations-when someone says something and a thought pops up.
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What happened in the classic case about distinguishing the types of memory and looking at the time course?
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An individual who had a declarative memory deficit but could train in procedural memory. ex. reading words backwards (like words from the backside of a window) you can get pretty fast at that. If you do this with an individual who has lost the ability to make a declarative memory (lost hippocampus and temporal lobe associated it) he will not be able to remember learning this procedure, but will be able to read just as fast as someone else trained the day before. BUT he will not be able to remember having ever learned it; if you asked the person, they would say that they had never done that before.
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What are the four temporal features of memory?
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1. Immediate memory: fraction of a second, and very large capacity
2. Working memory: seconds to minutes, if someone tells you a phone number, you keep repeating it until you can record it; you are using your working memory to get to where you can write it down. More focused capacity like searching for an object 3. Long-term memory: up to a lifetime 4. forgetting: removal of information not all memories are useful; tying up circuits that can use for something else. |
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Explain long-term memory.
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- consolidation: transfer memories from immediate and working memory to long term.
- reconstruction: most log-term memories are "reconstructed" as we "re-visit" and "re-code" reducing memory * If you don't keep going back to the memory, then chanes are it will get lost, but if you revisit and reconstruct it, permanency is enhanced but accuracy is lowered; memory is not about accuracy, we developed memory insofar as it aided and abetted survival; may remember something and then erase it and replace it with something that better meets our expectations; so reconstruction is essential but accuracy is affected. |
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What is the hippocampus not needed for?
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not needed for "immediate" and "working" memory., however, it is needed to form long term"declarative" memories
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What is the cortex for?
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information coming in through perforant pathway.
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What do you see in the schaffers and mossy fiber path?
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We see LTP and LTD in the schaffers, and there's another kind of LTP at the mossy fiber path with a different way of encoding memory.
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What is the function of the amygdala?
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It holds fear based memories (recall the paper where htey used tone related to a shock to see the role of LTP in fear memory
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For spatial learning what was the water maze experiment?
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Want the water opaque so the rat can't see the bottom. Put the rat in, so it has to swim, and it will want to find a hidden platform under the surface of the milky water. Rats can swim, but they don't like the water. The first time will find by accident; will learn that it was near the red square, for example and then it will swim straight to the platform next time it's put in the water.
-mean latency- means how long it takes for the rat to find the platform. So rats with intact hippocampi learn pretty fast and go straight to the platform; damage the hippocampus, it will not learn and it will be as though it was the first time every time |
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What is a problem that occurred for the spatial learning what was the water maze experiment?
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how do you know that the mouse isn't blind or sick when you take it out the hippocampus. Happens a lot-- maybe A caused B, B caused A or C caused both of them. There's more to go on than that now--see that it;s normal compared to other mice and the only difference is that it can't encode memory.
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What is the street-taxi drivers observation?
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famous for having a map in their brain for their ability to quickly find many locations in a complex city. Found that the london taxi drivers are lower in the anterior hippocampus, and their body and posterior hippocampus is bigger. Posterior is the part of the hippocampus found in other experiments to be associated with spatial learning. The longer that they were a cab driver, the bigger that posterior hippocampus is.
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What were some problems with the street-taxi drivers observation?
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maybe it's just self selection--people with bigger posterior hippocampi are more likely to become london taxi drivers rather than the other way around, they're just naturals. Also, is that really linear, or does that dip there have a meaning?
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How can the hippocampus get bigger?
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Can get bigger cell bodies, bigger dendrites, bigger projections, more glia. etc.. And it's also been found that there's an increased survival rate of adult-born neurons with more activity.
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What is the long-term storage for declarative information?
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(a variety of cortical sites: Wernicke's area for the meanings of words, temporal cortex for the memories of objects and faces, etc.)
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What is the short-term memory storage for declarative information?
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(hippocampus and related structures)
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What is the long-term storage for non-declarative information?
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(sites unknown but presumably widespread)
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What is the long-term storage for non declarative information?
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(cerebellum, basal ganglia, premotor cortex, and other sites related to motor behavior)
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True or False, can you examine what parts of the brain are firing during certain memories, what parts light up, and what memories are no longer retrievable with brain damage.
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True
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What parts of the brain are coordinated around fine motor movements?
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cerebellum (coordinated motor movement), basal ganglia, and premotor cortex.
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what are characteristics of the aging brain?
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1. deterioration
2. compensation 3. adult born neurons (hippocampus and olfactory system) 4. Alzheimer's disease and senile dementia |
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What happens in people with Alzheimer's disease?
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-decreased cholinergic signaling (cholinergic neurons die)
- Achase blockers--> slow down Alzheimer's -APP--> B amyloid peptides--> fibrils and aggregates. |
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In Alzheimer's disease the B amyloid peptides form fibrils and plaques in the brain--how can this causes Alzheimer's?
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The Beta amyloid binds to the alpha 7nAChR's and glutamates--importance not clear, lots of research not really understood.
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True or False, increase in size of the brain correlates with loss in function.
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False, decrease in size of the brain correlates with loss in function.
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Why is it that those who are old and still good at performing task are instead using additional locations versus a young person that has a certain part of the brain light up?
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This is compensation that is occurring because of the deterioration, less plastic, less LTP, things slow down; possible explanation? may develop compensatory mechanism to help with the challenge.
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What happens to long term memory when your hippocampus is damaged?
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memory formed long ago is still intact even in hippocampal damage. You can't make new memories for sure though. When your hippocampus is damaged, your working memory works find but you get distractions, and forget what is happening
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The experiment of Larry Squire done to a patient from Encinitas had suffered damage to his hippocampus. couldn't remember anything recently, but tested his long term memory. How would you do a quantitative test?
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Cross check his responses with other people who lived in Hayward and moved out. In his results, he could give perfect directions about the town from his childhood, but not in where he currently lived, or any new place.
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What are adultborn neurons, where do they end up, and what do they do?
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Generated in the dentate gyrus, they end up becoming granule cells that innervate CA3 pyramidal neurons via their own Mossy fibers. They appear to encode spatial and other
memory information. |
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One of the important events in early brain development is cell migration. What are two important results of cell migration?
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Brings neurons into different inductive environments; 2) enables synaptic connections.
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Define two ways in which cells in the central nervous system migrate.
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Radial migration:
1) Cerebellum: granule neurons migrate along Bergman astrocytes (outside to inside) 2) Cortex: pyramidal neurons migrate from inside to outside of the cortex Tangential migration in the cortex: Inhibitory GABAergic neurons (20% of neurons in the cortex) migrate from ganglionic eminences in ventral forebrain. |
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What will be a result of a mutation in reelin proteins?
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A protein that is important in detachment of neurons from glia. A mutation in reelin, such as the reeler mouse can cause the cortical layerings to become inverted.
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What will be a result of a mutation in doublecortin proteins?
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Is a protein that is expressed by neuronal precursor cells which is important for microtubules stability. A mutation in this protein can give rise to lissencephaly which a brain formation disorder that causes the cortex to become smooth
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What will be a result of a mutation in DLX1, DLX 2 proteins?
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a mutation in any of these two proteins leads to tangential
migration being blocked. |
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What is the big picture underlying the molecular basis of induction?
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Ligands bind receptors that signal to the nucleus and alter gene transcription
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Briefly describe three of the different molecular pathways of induction.
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i. RA (Retinoic Acid)
Binds to RA receptors--> Migrates to nucleus and binds DNA--> alters gene transcription ii. BMPs (Bone Morphogenetic Proteins) Bind to receptor serine kinases --> phosphorylate SMADS -->P-SMADS migrate to nucleus--> alter gene transcription iii. Shh (Sonic Hedgehog protein) Binds to patched + smoothened receptors--> causes Gli1 factor to dissociate from an inhibitory complex --> migrates to the nucleus--> alters gene transcription |
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What are the structures that were discussed in class that are required for declarative
memory? |
Hippocampus and amygdala
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On which part of the brain is spatial memory most likely dependent?
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Hippocampus
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What are the two experiments that show that the hippocampus is important for spatial memory formation.
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london street taxi cab drivers, and rats placed in murky water (Morris Water Maze Test).
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What are 2 compounds that you can apply to discover the birthdates of neurons?
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3H-thymidine or BrdU, both of which are DNA precursors that will be incorporated into DNA and are easily detected in cells that then stop DNA replication. Cells that continue to replicate DNA and divide will dilute out these labels, when they are only present transiently.
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Describe the essential elements of the Morris Water Maze Test in establishing the significance of the hippocampus in the formation of new memories?
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1) Investigated the effects of hippocampal lesion in rats during a spatial memory task
2) Two groups of rats: Control and rats with lesioned hippocampus 3) Task: Rats find “Resting” platform in unclear water. Recorded time to locate platform in each of 10 trials. 4) Results: Control rats showed reduced times over the course of 10 trials, lesioned rats showed no significant changes in time 5) Significance: Control rats were able to form/enhance spatial memory and recall it better with each trial, enabling them to locate rest spots faster. Lesioned rats demonstrated no time improvement in finding the rest spots, suggesting an inability to establish new spatial memory, a type of long-term declarative memory. 6) Conclusion: The hippocampus is needed to form new, long-term declarative memories. |
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would someone with damage to the hippocampus be able to recognizing a stranger whom they met yesterday?
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NO, hippocampal lesion/dysfunction would eliminate the ability to form new, long-term declarative memory (ex. used to recognize faces, names, etc.).
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would someone with damage to the hippocampus be able to recalling mental images of their childhood home?
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YES, long-term memories consolidated prior to hippocampal loss remain accessible.
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Consider the following situation. You are a novice researcher working with frog embryos. Out of boredom and curiosity, you take cells from the somites and place them in the region of the neural crest. What are you likely to observe?
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The implanted cells will likely differentiate into components that depend on their migratory pathway, since new environments will dictate the cells' ultimate fate.
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We know that during early nervous system development, sensory neurons are generated closer to the dorsal/roofplate side while motor neurons are generated closer to the ventral/floorplate side. You hypothesize that a factor encoded by gene X and secreted by a group of cells in the floorplate are necessary for motor neuron formation
and can suppress sensory neurons growing in from the dorsal side. How would you test this hypothesis? |
You can knock out gene X and see if over-growing sensory neurons “invade” into ventral side and motor neurons disappear. You can also increase local factor X
concentration by overexpression of gene X or microinjection to see if you can observe the opposite effect. |
