Learning and Memory Flashcards
Memory
the ability to store and retrieve information
Learning
acquiring new and enduring information leading to a modification of behavior
Retrograde amnesia
the loss of memories formed before the onset of amnesia
Anterograde amnesia
the inability to form memories after the onset of amnesia
Why did patient H.M have memory loss?
He suffered from seizures, the root of his seizures was in the medial temporal lobe, so his doctors removed the hippocampus and amygdala
What kind of memory loss did H.M experience?
extreme anterograde amnesia and minor retrograde amnesia
Mirror tracing task
H.M. could still learn, but he doesn’t remember ever learning. He got better at the task throughout the sessions but did not remember ever doing it
(non-declarative memory)
Declarative
things you know that you can tell others (hippocampus). Facts and information acquired through learning
Non-declarative
things you know that you can show by doing. Shown by performance rather than recollection
Delayed non-matching-to-sample task
object recognition memory test requiring monkeys to declare what they remember. Works by giving two objects to a monkey and always putting a treat under a new object that the monkey has not seen.
Delayed non-matching-to-sample task HYPOTHESIS
certain portions of the temporal lobe are required for the formation of new declarative memories
Delayed non-matching-to-sample task RESULTS
The more tissue that you take away, the more memory damage. The amygdala had no clear effects on memory.
What can disrupt new declarative memory?
disruption is due to damage to both to hippocampus itself, and to the nearby cortex
Patient N.A.
had amnesia due to accidental damage to the dorsomedial thalamus and mammillary bodies. No hippocampal damage, which suggests a larger memory network. He had short-term memory but could not form declarative long-term memories
Patient K.C.
could not retrieve personal memory due to damage to the cortex (frontoparietal cortex) and had some hippocampal shrinkage (not as important)
Where did Clive Wearing have damage?
damage to the temporal lobe, frontal lobe, and hippocampus
What is Clide’s function for episodic and semantic memories?
He has no episodic memory (retrograde and anterograde)
He cannot create new semantic memories, but he can remember old ones (anterograde)
What parts of the brain are responsible for episodic memory storage?
frontal and parietal cortexes
semantic memory
generalized declarative memory, more facts and knowledge
episodic memory
detailed autobiographical memory
What is the model of declarative memory formation
sensory processing in cortex → parahippocampal, entorhinal, perirhinal cortex → hippocampus → medical diencephalon including mammillary bodies → declarative memory storage in cortex
What will damage to the medial temporal lobe or the medial diencephalon/mammillary bodies prevent?
damage will prevent the formation of any new declarative memories, without the loss of previously formed memories
What are 4 types of nondeclarative memory?
Skill learning
Priming
Conditioning
Spatial memory
Skill learning
Learning to perform a challenging task through repetition. Skill learning is impaired with damage to the basal ganglia
Priming
A change in stimulus processing due to prior exposure to the stimulus. Appears to be a from reduced activity in the cortex.
Spatial memory
Found that the hippocampus is the biggest factor in spatial memory
Place cells: become active when someone is in a particular location
Associative learning
association between two stimuli, or between a stimulus and a response (classical and operant conditioning)
Classical conditioning
a previously neutral stimulus acquires the capacity to elicit a response through associations with a stimulus that already elicit a similar or related response (Pavlov)
Operant conditioning
a response becomes more or less likely to occur depending on the consequences (punish/reward)
Stages of memory
Sensory buffer
STMs
LTMs
Sensory buffer
the briefest recollection of sensory impressions (split-second)
STMs
usually last only for seconds, or throughout the rehearsal
LTMs
last for days or years
Processes in the functional memory system
Encoding
Consolidation
Retrieval
Encoding
sensory information is encoded into STM
Consolidation
information may be consolidated into long-term storage
How does STM work without an intact hippocampus?
STM can be encoded and retrieved without an intact hippocampus
But…
an intact hippocampus is required to consolidate declarative STMs into LTMs
How do strong emotions enhance memory formation?
emotional event → adrenal glands → epinephrine/norepinephrine → amygdala
What role does synapses play in learning and memory formation?
involves changes in the strength of synapses in response to biochemical signals
What role does neurogenesis play in memory formation?
Memories can also require the formation of new synapses or the birth of new neurons
What evidence is there that H.M had intact procedural memory but not declarative?
He got better at the mirror tracing task over time
What may explain why H.M. still had retrograde episodic memory intact, but Clive Wearing did not?
Clive had damage to his frontal lobe, but H.M. did not.
Which brain region is involved in spatial memory? What are place cells?
The hippocampus, place cells are fired when we are in a specific location or place
What is the neural mechanism in which strong emotions enhance memory formation?
the adrenals glands, epinephrine/norepinephrine
Rats housed in enriched conditions developed…
- heavier, thicker cortex
- enhanced cholinergic (acetylcholine) activity
- more dendritic branches & spines on cortical neurons
- larger cortical synapses
- more neurons in the hippocampus
- enhanced recovery from brain damage
