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64 Cards in this Set
- Front
- Back
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Difference between learning and memory? |
Learning - how experience changes the brain Memory - How the changes are stores and later activated |
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Who was H.M.? What was important about him, and the procedure he had? |
Man with greatest contribution to our understanding of neuropsychology of memory Had a bilateral medial temporal lobectomy for epilepsy treatment --> Led to memory deficits Intact collection of old memories - but couldn't form any new memories |
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Define lobectomy vs. lobotomy? |
Lobectomy: Lobe is REMOVED from brain Lobotomy: Lobe is SEPARATED from brain |
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What was the "Digit Span + 1 Test" for H.M.'s anterograde amnesia? |
Repeat 5 digits, and then after a few trials a new digit is added - HM stuck at 8 digits for 25 trials (Normally you can get to 15 digits after 25 trials) |
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What was the "Block-Tapping Memory-Span Test" for H.M.'s anterograde amnesia? What did it prove? |
Array of 9 blocks laid out - must be tapped in a certain, increasing sequence - he was stuck at 5 no matter how many trials... - Showed global amnesia was present (Information in all sensory modalities, not just verbal material) |
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What was the "Mirror-Drawing" for H.M.'s anterograde amnesia? What did it show? |
Had to trace an image while looking in a mirror - the performance improved significantly over multiple practice sessions - Showed unconscious forms of memory retention |
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What was the "Incomplete-Pictures Test" for H.M.'s anterograde amnesia? What did it show? |
Had to identify different sets of fragmented images (i.e. Incomplete) - HMs performance improved over time: Unconscious memory retention |
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What was the "Pavlovian Conditioning" for H.M.'s anterograde amnesia? What did it show? |
HM trained to blink his eyes at the sound of a tone that resulted in a puff of air Years later the tone still elicited the blink - Showed unconscious memory retention |
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What were 3 major scientific contributions of HMs case? |
1) Medial temporal lobes play an important role in memory 2) Bilateral medial temporal lobectomy abolishes the ability to form long-term memories 3) An amnesic patient might claim no recollection of a previous experience, while still demonstrating memory for it |
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What are mnemonic processes? |
Memory-related processes |
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What is remote memory? |
Memory for experiences in the distant past |
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What is memory consolidation? |
The translation of short-term memories into long-term memories |
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What are explicit memories vs. implicit memories? |
Explicit: Conscious long-term memories Implicit: Unconscious long-term memories (Demonstrated by improved task performance) |
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What happens to your memory abilities with medial temporal lobe amnesia? |
Retainment of implicit memories, but inability to retain explicit memories |
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What are repetition priming tests? |
Tests that assess implicit memory (I.e. Incomplete pictures or words test) |
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Advantage between implicit/explicit memories? |
Implicit: First to evolve because it is more simple Explicit: Advantage is flexibility (Implicit cannot be used in a different way) |
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What are the 2 categories of explicit memories? |
Semantic memories: Explicit memories for general facts or information Episodic memories: Explicit memories for particular events of one's life |
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With medial temporal lobe amnesia, which type of explicit memory remains largely intact? |
Semantic memory - i.e. Things you learn in school become "ingrained" |
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When you experience cerebral ischemia, what can occur? From damage to what area? |
Medial temporal lobe amnesia, from damage to the CA1 subfield of the pyramidal cell layer |
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What is Korsakoff's Syndrome? |
Disease from thiamine deficiency (Heavy alc. consumption) Sensory/motor problems, confusion, personality changes |
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How is Korsakoff's syndrome similar to medial temporal lobe amnesia? |
Anterograde amnesia is the most commmon symptom (But Korsakoff's can develop retrograde) |
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If a Korsakoff's patient is examined post-mortem, where will damage be found? |
To the medial diencephalon Also: - Neocortex - Hippocampus - Cerebellum |
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What is another name for Korsakoff's syndrome? |
Medial diencephalic amnesia |
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Explain amnesia of alzheimer's disease? |
Mild deterioration occurs (before the dementia) in memory - Anterograde and retrograde amnesia, so deficits are in short-term memory as well |
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What is a major cause of alzheimer's? Where does the damage occur? |
ACh depletion, due to degeneration of the basal forebrain VERY diffuse damage - medial temporal lobe - prefrontal cortex - basal forebrain structures |
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What is posttraumatic amnesia? |
After a blow to the head resulting in a coma - the patient shows retrograde amnesia (for the events leading up to the hit) and anterograde amnesia (for the evens sometime after the hit) The duration of these amnesias are longer than the coma itself |
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What are islands of memory? |
Surviving memories for isolated events, that occur during periods where other memories are wiped out (I.e. the little things that people remember) |
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What is Hebb's theory? |
Memories of experiences are stored short-term by closed neural circuits - susceptible to disruption Eventually structural changes are induced, and long-term storage occurs |
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What is electroconvulsive shock (ECS)? How was the effectiveness tested? Finding? |
Intense, brief seizure-inducing shock delivered via electrodes to the brain to disrupt neural activity of short-term memories (not yet stored) Tested by rats/water spout (I.e. Find the spout, get a shock, see if they remember where the spout is) 10mins - 1hr period of consolidation (But others have found periods contradicting Hebb's theory of consolidation...up to a few years) |
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What is the "Standard consolidation theory"? |
Memories are temporarily stored in the hippocampus until they can be transferred to a more stable cortical storage system |
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What is the "Multiple-tract theory"? |
(Since retrograde amnesia gradients can be very long, supported here): Hippocampus (or elsewhere) stores memory forever, but the link to the memory is strengthened each time it is recalled - A new engram, or change in the brain storage of memory, is established to the original engram |
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What is the reconsolidation hypothesis of memories |
When a memory is retrieved from long-term storage, it is held in labile (unstable) memory - susceptible to post-traumatic amnesia until reconsolidated, anyways |
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What were the 2 issues faced when developing animal models of HMs medial temporal lobe amnesia? |
1) Didn't yet understand that HMs anterograde amnesia didn't extend to all kinds of long-term memories (Just thought to be implicit) 2) Thought amnesic effects of lesions were due to hippocampal damage - so animal models had hippocampal lesions |
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How did they test the success of the creation of an animal model of medial temporal lobe amnesia? (In 1970s) |
Animal delayed nonmatching-to-sample test: Monkey presented with food under a shape....then exposed to that and a new shape - and had to guess where the food was under |
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From the animal model of medial temporal lobe amnesia, which 3 major temporal lobe structures were found to be important? |
Hippocampus Amygdala Rhinal cortex |
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What is a Mumby Box used for? |
To perform the delayed nonmatching-to-sample test in rats |
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How do we induce medial temporal lobe amnesia in rats vs. monkeys? |
Monkeys - we aspirate it (suck it out) Rats - lesion it electrolytically or with neurotoxin injections Areas in question: Hippocampus, amygdala, and rhinal cortex |
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What is the neuroanatomical paradox of medial temporal lobectomy? Solution? |
Rhinal cortex removal produces deficits in object recognition, but hippocampus removal does not. BUT, ischemia-produced hippocampal lesion produces deficits. Solution: - Ischemia produced CA1 hyperactivity, damaging hippocampus-surrounding structures - Extrahippocampal damage responsible for object-recognition deficits - Damage comes FROM the hippocampus - cannot be lesioned |
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What are the 2 areas of the rhinal cortex? Which part is important in object recognition? |
Entorhinal Cortex: Cortex within the rhinal fissure Perirhinal Cortex: Cortex around the rhinal fissure - Important for object recognition |
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The hippocampus is confirmed to play a role in ___________ recognition |
Spatial recognition |
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What part of the brain is important for spatial recognition? What about object recognition? |
Spatial: Hippocampus Object: Perirhinal cortex |
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What two animal memory tests are made significantly harder which hippocampal lesioning? Which two types of memory are greatly impaired with hippocampal lesioning? |
Morris water maze, and radial arm maze test Reference memory - memory of principles/skills required to perform task Working memory - Temporary memory required for successful performance of task |
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What are place cells? Where are they found? |
Fire when a subject is in the "place field" of the neuron, a specific location basically (e.g. Certain part of a maze) - Hippocampus |
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What are grid cells? Where are they found? |
Neurons with a flexible array of evenly spaced place fields - Entorhinal cortex (Basically help the hippocampal place cells obtain their spatial-location information) |
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What are the 3 kinds of cells in the entorhinal cortex? |
Grid cells: Important in spatial awareness Head-direction cells: Tells us orientation of the head Border cells: Fires when subject is near borders of immediate environment |
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Difference between grid cells and place cells? |
Grid - Respond reflexively to location Place - Respond to PLACE |
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How does food-caching affect the brain? |
Implies greater spatial awareness, and so you need larger hippocampuses than non-food-caching species |
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What is the cognitive map theory? How does it explain hippocampal function? |
Several systems in the brain specialize in memory, but for different kinds of information (E.g. Hippocampus - spatial location memory) Hippocampus thought to construct allocentric maps (representations of space in relation to a landmark) of the external world Also hippocampus thought to play a role in episodic memory, because of spacial context playing a role in acquiring the memory of an episode |
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What are 3 criticisms of the cognitive map theory? |
1) Firing of place cells are dependent on more than just spatial location 2) Hippocampal damage can impair task performance with no spatial awareness component 3) Hippocampus is a large, complex structure (probably not a "single-function" unit) |
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How are memories stored in the brain? |
Diffusely, and become more and more resistant to disruption over time |
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How do the following structures play a role in memory storage? Hippocampus Perirhinal cortex Mediodorsal nucleus Basal forebrain |
Hippocampus - Spatial memory Perirhinal cortex - object memory Mediodorsal nucleus - Implicated in memory by Korsakoff's disease Basal forebrain - Implicated in memory by Alzheimer's disease |
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What is the purpose of the inferotemporal cortex in memories? |
Important for storing sensory memories |
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What is the purpose of the amygdala for memories? In once case of bilateral damage to amygdala, what happened? |
Plays a role in memories with emotional significance of experiences In one case, couldn't induce startle response for various stimuli - even though there was explicit memory for the training - Doesn't actually store memories, but strengthens the emotional connection to the memories themselves |
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What is the purpose of the prefrontal cortex for memories? With lesions, what 2 episodic memory abilities are often lost by patients with prefrontal lesioning? |
Important for cognitive processes, and episodic memory abilities With lesioning, large anterograde and retrograde deficits are present (specifically for the temporal order of events) -- Also, there are deficits in working memory |
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What is the purpose of the cerebellum for memory? |
Participates in the storage of memories of learnt sensorimotor skills |
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What is the purpose of the striatum for memory |
Thought to store memories for consistent relationships between stimuli/responses (I.e. Memories that develop over many trials) |
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What is long-term potentiation? |
The idea that facilitation of synaptic transmission occurs with high-frequency electrical stimulation applied through presynaptic neurons Facilitation lasts for a while after the initial stimulation |
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What is Hebb's Postulate for Learning? |
LTP develops ONLY if the presynaptic neuron fires, and is accompanied with a firing of the postsynaptic neuron |
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At synapses where LTP is studied, what are 2 events required for maximal response of the NMDA receptor? |
(NMDA - For glutamate) 1) Glutamate must bind 2) Postsynaptic neuron must already be depolarized, partially - This is so that calcium channels are partly open --> When LTP occurs calcium sees BIG INFLUX to trigger the AP - Allows the neural network to learn associations |
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What type of compounds can block LTP induction? |
Protein kinase inhibitors |
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LTP Storage/Recall Questions: a) What signal transmits from post-syn to pre-syn neurons? b) _______ play a role in synaptic transmission |
a) Nitric oxide b) Astrocytes |
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Where does LTP typically get studied? Where else in the body does it occur? |
Mostlye NMDA-receptor-mediated LTP in the hippocampus - but documented in many other parts of the CNS |
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What are 2 studies that proved the preservation of implicit memories, even with infantile amnesia occurring? |
Infantile amnesia: Inability to remember event's of one's infancy Study 1: Large skin conductance response to photographs of preschool classmates Study 2: Performance on incomplete-pictures (fragmented drawings) test had better results for pictures seen 3 months prior, compared to the control images |
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What are nootropics? Do they work? |
Smart drugs, thought to improve memory - No. |
