Chapter 17: Learning and Memory Flashcards
how do memories start?
as senses; visual, auditory, olfactory and tactile
sensory buffers
element of the type of memory that stores the sensory impression of a scene
short-term memory
form of memory that lasts for seconds, or as long as rehearsal continues, especially while being used during performance of a task
what brain structure does short-term memory use?
prefrontal cortex
working memory
type of short term memory that holds a limited amount of information available for ready access during performance of a task (less than 30 seconds)
intermediate term memory
form of memory that lasts longer than short term memory but shorter than long term memory
long term memory
enduring form of memory that lasts days, weeks, months or years and has a large capacity
stages of memory
- incoming information from senses
- a subset of the sensory information enters sensory buffers is encoded and placed into short-term memory
- if the information is rehearsed or used, it may be consolidated into long-term memory lasting minutes up to a lifetime
- when we probe a participant’s memory, they must retrieve information from LTM and place it into working memory to perform a task, such as reporting the items on a list
- at any stage, information may be forgotten
senses»_space;> sensory buffer»_space;>STM»> consolidated to LTM»_space;» retrieved from LTM for working memory
encoding
stage of memory formation where information entering sensory channels is passed into short term memory
consolidation
stage of memory formation in which information in short-term or intermediate-term is transferred into long term
retrieval
process in memory where a stored memory is used by an organism
what things are picked for long-term memory storage?
rehearsed information
memories connecting with old information
memories connected with emotional arousal
what does emotional arousal activate?
peripheral stress hormone and amygdala
what does the amygdala do?
sends axons to other brain structures to influence how they process information
- can also strengthen other regions
what did patient H.M suffer from after his surgery?
anterograde amnesia
what activates amygdala?
stress hormones which causes cortisol to affect those other brain regions that the amygdala sends axons to
what surgery did patient H.M recieve?
bilateral medial temporal lobectomy
anterograde amnesia
inability to form new memories beginning with the onset of a disorder
what brain structures does the bilateral medial temporal lobectomy remove?
hippocampus, amygdala and cortices around hippocampus
what was affected by his anterograde amnesia?
long-term memory
what theory about memory did patient H.M explain?
storage vs. consolidation because he could remember past memories but could not form new ones
what did patient H.M suggest?
memories are monolithic: there are different kinds of memories
what experiment did they do on patient H.M and what did it show?
mirror tracing
- he was given a task in the form of a motor skill, and he improved everyday but he could not recall doing the task
what two types of memory does long-term memory consist of?
declarative and nondeclarative
declarative memory
things you know that you can tell others
can declarative memory be tested in humans?
yes because they can talk
was patient H.M able to form new declarative memories?
no
what two subcategories is declarative memory broken down into?
episodic and semantic
episodic memories
personal memories of life events
what brain structures to episodic memory involve?
medial temporal lobe and neocortex
semantic memory
general knowledge of the world
what brain structures does semantic memory involve?
medial temporal lobe and neocortex
nondeclarative memory
things you know that you can show by doing
can nondeclarative memory be tested in animals?
yes, and humans
was patient H.M able to form nondeclarative memories?
yes, it showed through the mirror tracing experiment
what are the three subcategories of nondeclarative memory?
skill learning, priming and conditioning
skill learning
learning to perform a task that requires motor coordination
what brain structures does skill learning involve?
striatum, motor cortex and cerebellum
priming
exposure to a stimulus facilitates subsequent response to the same or similar stimulus
example of priming
being more likely to use a word that you heard recently
what brain structure does priming involve?
neocortex
conditioning
neutral stimulus acquires the power to get the response normally received by another stimulus after the two stimuli are paired
example of conditioning
salivating when you see your favorite food
what brain structures does conditioning involve?
amygdala and cerebellum
what brain structures does nonassociative learning involve?
involves reflex pathways
what brain structures does spatial memory involve?
hippocampus and cortex
what type of brain damage did patient N.A suffer from?
damage to diencephalon, parts of the thalamus and hypothalamus connections, including the mamillary bodies
did patient H.M and N.A have similar symptoms? and what was the major difference between the two
yes, but patient N.A did not have damage to hippocampus
what did relationship between patient N.A and H.M suggest?
parts of diencephalon and hippocampus work together in formation of new memories
korsakoff’s syndrome
due to thiamine deficiency, results from alcoholism
what are characteristics of korsakoff’s syndrome?
failure to recall past events and recognize familiar objects
- deny anything is wrong with them and are often confabulate
confabulate
fill a gap in memory with falsification
what brain structures are damaged with korsakoff’s syndrome?
mamillary bodies and basal frontal cortex
what is important to form declarative memories?
medial thalamus and mamillary bodies
mamillary bodies
important system connecting medial temporal regions to thalamus
what brain damage did patient K.C sustain?
damage to cortex
what type of memories could Patient K.C retrieve?
personal memories but not good general knowledge
model for how declarative memories are formed and stored
Sensory processing in cortex»_space;parahippocampal, entorhinal, perirhinal cortex» hippocampus» medial diencephalon, including mammillary bodies» declarative memory storage in cortex (perhaps layer 1)
primacy vs recency effect
tells us we have different TEMPORAL stages of memory
lesion studies
difficult to distinguish stages
what produces smaller effect: hippocampus legions or hippocampus plus nearby cortical areas
hippocampus legions
fMRI
looks at activity during learning and look at how well people do during test a week later, can also look at activity during retrieval
what brain structures are important for consolidation and retrieval?
hippocampal system and prefrontal cortex
what is the theory for consolidation and retreival?
hippocampus helps put memories into cortex, helps them consolidate over time
where are memories stored?
in parts of cortex near sensory cortex involved in memory (neocortex)
place learning
learning to orient yourself and go to the location
where does place learning occur?
hippocampus
habit learning
learning to make the same motor response
where does habit learning occur?
caudate nucleus
cognitive map
understanding of the spatial organization
what is key for building cognitive map?
hippocampus
what type of cells does the hippocampus have?
spatial cells and place cells
what is the process to form place cells?
grid cells feed into the hippocampus
hippocampus
organizes relationships among lots of information including space, time, etc
what forms the basis for declarative memory function?
hippocampus
what three mechanisms induce synaptic changes?
- environment enrichment
- aplysia and simple learning
- hippocampus and long-term potentiation
how are memories stored?
changes in the brain
neuroplasticity
ability of neurons and neural circuits to be remodeled by events
how is neuroplasticity seen?
by electrically stimulating cells and recording postsynaptic potentials
long term potentiation
repeated fast stimulation of the presynaptic cell can lead to a long-term increase in the post synaptic response
memories can be stored by:
- changes involving synaptic transmitters which include greater release of neurotransmitter molecules and/or greater effects because the postsynaptic membrane becomes larger or sensitive. these changes enlarge the pre and postsynaptic synapse and result in increased postsynaptic potential
- modulation by interneurons which causes hyperpolarization or depolarization of the axon terminals and changes in the amount of neurotransmitter released
- formation of new synapses or rearrangement of current ones
changes in synapse can be ______
physiological (more NT released) or physical (formation of new synapse)
what occurs during change in receptor sensitivity?
ions are allowed to pass through receptor-channel
what is the environmental enrichment experiment?
animals are housed in large social groups in special cages with toys and other features
what does the environmental enrichment experiment show?
enhanced opportunity for learning perceptual, motor skills and social learning
what brain structure is heavier and thicker in animals who are environmentally enriched?
cortex
what happens to the cortical neurons of environmentally enriched animals?
their cortical neurons have more dendritic branches, especially on dendrites closer to the cell body
what happens to the cortical synapses of environmentally enriched animals?
cortical synapses are larger and there are more
what are the findings of the environmental enrichment experiment?
environment dramatically alters basic physiology and structure of brain
aplysia
shows habituation and sensitization of reflexes: simple kinds of learning and memory
habituation
organism becomes less responsive following repeated presentation of stimulus
sensitization
organism becomes more responsive to most stimuli after being exposed to unusually strong or painful stimulation
siphon-withdrawal reflex
touch the siphon of sea slug and it will retract its gill but with repeated stimulation, it will retract its gill less and less because it learns there is no danger
what is the siphon-withdrawal reflex caused by?
changes in the synapse between the sensory cell that detects touch and the motor neuron that retracts the gill
can the siphon withdrawal reflex habituate or sensitize?
both
do short term and long term memories have the same mechanisms?
no
what causes short term habituation in the sea slug?
the sensory neurons releases less transmitter
what causes the long-term habituation in the sea slug?
due to retraction of some synaptic terminals
long-term potentiation
potentiated response of postsynaptic neurons
what three pathways does long-term potentiation occur in?
- perforant pathway
- mossy fiber pathway
- schaffer collaterals
perforant pathway
entorhinal cortex to dentate gyrus
moss fiber pathway
dentate gyrus to CA3 pyramidal cells
schaffer collaterals
CA3 pyramidal cells to CA1 pyramidal cells
normal synaptic transmission
NMDA receptor is voltage gated because a MG2+ ion blocks the channel unless the cell is already depolarized
does the NMDA receptor open in a normal synaptic transmission
no, a single release of NT would not open the NMDA receptor
induction of long-term potentiation
stimulating the presynaptic terminal rapidly in succession causes depolarization and more NT release which causes the NMDA receptor to open and Ca2+ rushes in
why is calcium special?
activates a variety of intracellular signaling molecules
enhanced synapse, after induction of LTP
after induction of LTP, there may be more AMPA receptors, which creates larger postsynaptic receptors and more NT release with single stimulation, and larger postsynaptic response
what happens after time has passed and new proteins are made after the process of LTP?
larger synapse with more of everything inside the synapse
earlier stages of long term potentiation
earlier stages last an hour and depend on change in receptor channel properties and change in number of receptors
earlier stages of LTP do not depend on
protein synthesis required for later stages of LTP
correlational observations
time course of LTP is similar time course of memory formation
somatic intervention
things that block LTP also block memory formation
behavioral intervention
training in a memory task creates LTP in the brain
where are new neurons always being produced and what is it crucial for?
dentate gyrus and crucial for learning
what do older adults show deficit in?
working memory and retrieval of memories (especially if there are no external cues and requires effort)
what may help trigger memories for older adults?
external cues
what are the causes of memory deficits in older adults?
- impairments in encoding and retrieval, less brain activation
- loss of neurons and neural connections
- deficits in cholinergic transmission: problems in basal forebrain system
preventing or alleviating aging on memory
- environmental conditions
- involvement in stimulating activities
- spouse with high cognitive status
- exercise