Exam 3 Flashcards
Sensory Memory
milliseconds to seconds
Iconic memory, echoic memory
Short-Term Memory/Working Memory
seconds to minutes
REHERSAL
Long-Term Memory
days to years
not really about a passage of time: when falls below level of consciousness
RETRIEVAL
Global Amnesia
profound forgetfulness
Regardless of modality of information (names, faces, places, odors and music all forgotten)
Regardless of how information is presented (visual, auditory, olfactory)
Amnesiac syndrome: impaired declarative but spared nondeclarative
amnedia tends to spare nondeclarative memory
Retrograde Amnesia
inability to remember prior memories
Anterograde Amnesia
inability to form new memories
Patient H.M.
severe epilepsy; seizures starting at age 15
bilateral removal of MTLs (hippocampus, but posterior hippocampus still present)
William Scoville
Anterograde amnesia – since lesion
Suggests encoding deficit
Retrograde amnesia – prior to lesion
Suggests consolidation deficit
temporally graded retrograde amnesia
Memory consolidation takes time
This is because the neural pathways of newer memories are not as strong as older ones that have been strengthened by years of retrieval and CONSOLIDATION
Episodic Memory
Events (declarative/explicit)
Semantic Memory
Facts (declarative/explicit)
Procedural Memory
Skills (non-declarative/implicit)
Medial Temporal Lobe
Monkeys!!!
Hebbian Learning
“When an Axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased”
- found in hippocampus
- the cellular basis of learning involves strengthening of a synapse that is repeatedly active when the post synaptic neuron fires
- repeated activation causes A’s efficiency, as one of the cells firing B, to increase
- synapses that are active at the same time that the post synaptic neuron fires are strengthened over time
Mechanisms of LTM
Long-term potentiation (LTP)
Hippocampus
NMDA/ AMPA receptors
LTP
long-term potentiation
(LTP) is a persistent strengthening of synapses based on recent patterns of activation
long-term increase in excitability of a neuron to a particular synaptic input caused by repeated high-frequency stimulation to that input
- Repeatedly stimulate a single pathway in hippocampus slices.
- Afterwards, new stimulation caused greater excitatory post-synaptic potential
- This is long-lasting…And Hebb was right!
- It works because of NMDA receptors!
Hippocampus
Hebbian learning/LTP occurs here
Iconic v. Echoic Memory
Unlike visual memory, in which our eyes can scan the stimuli over and over, the auditory stimuli cannot be scanned over and over.
Overall, echoic memories are stored for slightly longer period
While seeing something or touching something is a repeatable and reoccuring event (speaking in terms of short intervals), hearing is a single occuring event. It was probably an evolutionary benefit to keep and process the auditory input better.
last longer than iconic memory because what you have in the basilar membrane vibrating in your cochlea. As a result, it continues to have some kind of sensation and causes action potentials
Types of Memory
Sensory Memory (mil-sec)
Short-Term/W Memory (sec-min)
Long-Term Memory (days-yrs)
Types of Long-Term Memory
Declarative (explicit m)
Non-declarative (implicit m)
Declarative (explicit)
Semantic (facts)
Episodic (events)
Non-Declarative (implicit)
Procedural (motor skills, ex: riding bike)
Perceptual
Classical Conditioning
Nonassociative Learning (habituation sensitization
Perceptual Memory
Perceptual memory, that is the ability to interpret
incoming stimuli by recognizing individuals, by
categorizing them, and by noting relationships
between such individuals and categories, is ubiquitous
among animal species, as is the learning of these
facilities
Animals of all sorts can identify food sources, potential
mates, potential predators, etc. Pigeons have been taught to
categorize using such concepts as tree, fish, and human,
some well outside of their evolutionary background
(Herrnstein 1984). Honey bees have been taught to identify
human letters independently of size, color, position or font
Findings of Brenda Miller
IQ better than pre-op (112)
Fewer seizures
Memory System
See paper
Amnesia Timeline
See paper
H.M. Memory Timeline
See paper
H.M Types of Memory Deficits
DECLARATIVE: lost and impaired
EPISODIC: complete loss (couldn’t remember new people/events)
SEMANTIC: impaired, but some left in tact (rock’n’roll)
NONDECLARATIVE: spared
WORKING: intact
- normal digit span (could count, remember #s, but constant rehersal needed otherwise forgotten upon interruption)
PROCEDURAL MEMORY: intact
- mirror tracing, pursuit rotor tracing, Implicitly familiar w testing equipment, ant amnesiacs can still learn piano pieces
- HM could do priming conceptual task (fish card fill-in)
- Tower of Hanoi (improved, procedural learning, does not remember doing so though)
Temporally Graded Retrograde Amnesia
Memory consolidation takes time!
Occurs because the neural pathways of newer memories are not as strong as older ones that have been strengthened by years of retrieval and CONSOLIDATION
hippocampal memory trace
but cortical reinstatement
Memory in the Brain
Hippocampal activation greater during successful remembering (compared to unsuccessful attempts to remember)
Cortical activity patterns are reinstated in appropriate parts of cortex
Bliss & Lomo
stimulate CA3 –> output measured in CA1
- Repeatedly stimulate a single pathway in hippocampus slices.
- Afterwards, new stimulation caused greater excitatory post-synaptic potential
- This is long-lasting…And Hebb was right!
- It works because of NMDA receptors!
NMDA’s role
- LTP is dependent on NMDA receptors
- Mg=agonist that has block on NMDA receptor
- Opens upon high-frequency stimulation , allowing Ca to flow in; activation of NMDA receptors triggers LTP
Agonist/Antagonist
agonist: molecule that occupies receptor and activates
antagonist: molecule that occupies receptor and blocks
- Mg, AP5
NMDA and AMPA
- Both glutamate receptors
- Binding by glutamate should open channel, but not when Mg in place
- Receptor opens upon high-fq stimulation (Mg block removed, allowing Ca to flow in)
- Ca influx generates series of intracellular chemical cascades
- when these cascades reach the post-synaptic terminal, this activity results in LTP
Morris Water Maze
goal: assess importance of NMDA receptor in learning
circular opaque pool
water-averse rat
platform hidden
NMDA antagonist: AP5 – administered to select rats
control + AP5 rats–> thrown in water to learn platform location
when platform taken away…
CONTROL: biased to platform quadrant
AP5 rats: random swimming
–> NMDA RECEPTOR ANTAGONIST BLOCKS SPATIAL LTM
administer AP5 after learning..no effect
AP5 critical during learning, not important for RETRIEVAL; once a memory has been formed/LTP has occured, NMDA receptor no longer needed
AP5
NMDA antagonist
blocks LTP by binding to NMDA receptor but DOES NOT interfere with regulatory synaptic transmission
NMDA RECEPTOR ANTAGONIST BLOCKS SPATIAL LTM
Complementary Learning Systems Model
Mclelland & O’Reilly
LTP consists of two forms of memory:
specific episodes (episodic)
generalized patterns (semantic)
Pattern separation (formation of distinct episodic memories) is FUNDAMENTALLY INCOMPATIBLE with pattern completion (abstraction of specific episodes to inform general principles)
Rapid retention of arbitrary associations /= cannot be supported by the same system that encodes for generalized principles (a necessarily slow process)
—-> SUGGESTS THAT…
The hippocampus rapidly learns episodic memory…
the way a mem is reinstated
[IN FULL DETAIL] [IN GENERAL PRINCIPLE]
determines whether it will be transferred to the cortex as an episodic or semantic memory
Pattern Completion v. Pattern Separation
Pattern Separation: Formation of distinct episodic memories; Rapid retention of arbitrary associations
Pattern Completion: The abstraction across specific episodes to distill and/ or update general principles; Slow process of abstracting generalized principles
Systems Model, evidence for…
- Hippocampal activation greater during successful remembering (compared to unsuccessful attempts to remember)
- Cortical activity patterns are reinstated in appropriate parts of cortex
Components of Systems Model
- Encoding: hippocampal activity should be greater during successful encoding compared to unsuccessful encoding
- Retrieval: hippocampal ‘memory’ should be reactivated during successful remembering
- Retrieval: cortical activity is reinstated in appropriate regions of cortex (depending on what you can recall.)
Systems Model: Hypothesis 1
Encoding: hippocampal activity should be greater during successful encoding compared to unsuccessful encoding
Systems Model: Hypothesis 2
Hippocampal Retrieval: hippocampal ‘memory’ should be reactivated during successful remembering
Systems Model: Hypothesis 3
Coritcal Retrieval: cortical activity is reinstated in appropriate regions of cortex (depending on what you can recall.)
Consolidation
stabilization of a memory trace after its initial acquisition
process in which hippocampus-dependent memories become independent of the hippocampus over a period of weeks to years
Pattern Completion
Partial input serves as memory cue, reinstating hippocampal network pattern of activity, this is known as pattern completion.
Systems Model Process
- Experience leads to a cascade of brain activity (visual, spatial, auditory, etc.).
- This distributed, parallel processing of brain activity is inputting into the hippocampus.
- The hippocampus turns this input into its own pattern of activity, generating a network ensemble.
- The more strongly this network becomes interconnected, the more likely you are to remember that experience (dependent on LTP and replay during sleep and rest).
(Retrieval)
- Partial input serves as memory cue, reinstating hippocampal network pattern of activity, this is known as pattern completion.
- If hippocampal ensemble does pattern complete, this leads to cortical reinstatement. Cortical reinstatement/reactivation is what gives rise to conscious experience of remembering.
- Hippocampal Activity –> 2. Hippocampal Reinstatement –> 3. Cortical Reinstatement
Subsequent Memory Paradigm
Assessing whether hippocampal activity during encoding be predict subsequent memory
measures: imaging data, recall ability
- Look at list of words, record BOLD responses.
- Memory test (equal # of new, old words).
Words with greater brain activity should be remembered better. Imaging data should correlate with % correct words.
Significantly greater activity for words remembered than forgotten.
Indexing item and source memory
subsequent memory task
(1) Imagine a scene (2) read word backwards
Testing for: Object and Context
Perirhinal Cortex activity: greater activation for remembered objects
Hippocampus: greater activation when both remembered
SUGGESTS THAT…
Hippocampus is important for encoding patterns/associations
Simpsons Experiment
Neuron reactivated right before recall
Same neurons during experience are again activated during retrieval
reinstatement within the same neuron; N 46 in hippocampus
Memory Retrieval
Auditory pairing, visual pairing
Cat-meow, Cat-pic
Auditory reinstatement even without auditory stimulus
SELECTIVE REINSTATEMENT
CONTENT-DEPENDENT
Cortical activity is reinstated in appropriate regions of cortex (depending on what you can recall)
Memory Reactivation
paired associates
scene, face, object
computational classifier: train pattern classifier to predict visual category from brain activity
no pic, just looking at cue (Oprah pic)
FLAG –> I remember scene, face, or object
Sleep and Rest
The more strongly this network becomes interconnected, the more likely you are to remember that experience (dependent on LTP and replay during sleep and rest).
Tambini & Davachi (2013) study
Memory consolidation is thought to depend on the reactivation of patterns of brain activity that characterize recent experience
patterns of hippocampal connectivity that characterize an encoding experience persist into immediate rest periods. Furthermore, this persistence is related to memory for the preceding representations, suggesting that postencoding measures of persistent activity patterns may contribute to memory consolidation
what does hippocampus activity look like
is evidence that pattern of activity persists into replays during rest; patterns of hippocampal activity most similar during immediate rest period
experience-dependent changes in brain function
Cued Memory Activation
Information acquired during waking can be reactivated during sleep, promoting memory stabilization.
performance was more accurate for the cued compared to the uncued sequence
Place Cell
A place cell is a type of pyramidal neuron within the hippocampus that becomes active when an animal enters a particular place
Fragments Task
Warrington & Weiskrantz
performance on two memory tests administered 10 minutes after the presentation of 16 words.
Amnesic patients performed as well as control subjects on what the authors termed a “cued recall” task, in which the first three letters of a studied word (so-called “word stems”) were presented and the subject was “required to identify the stimulus word”
The patients were markedly impaired, however, on a test of Yes/ No recognition.
amnesia was better characterized by “altered control of information in storage” (p. 419), rather than a consolidation block. That is, they argued that new information “gets in there” but that the amnesic syndrome makes it more difficult to access this information.
Priming
Facilitative changes in the ability to identify, generate, or process an item due to a specific encounter with the item
priming may reveal the workings of implicit memory
Repetition Suppression
A reduction of neural response that is often observed when stimuli are presented more than once, compared to novel stimulus
repetition priming –> repetition suppression
Repetition Priming
facilitative processing
rt speed up
Visual Word-Form Priming
same font-different font
no change in priming RT in MS
suggesting that MS brain lacks perceptual sensitivity
visual cortex damage ; R
__
R (visual-specificity hem)
R hemisphere processing is more visual-spatial
L hemisphere processing is more perceptual verbal
Priming dependent on font in R hemisphere
Same font better recall
–
different forms of priming
perceptual and conceptual priming
Valence vs Arousal
Avoidance (negative) vs Approach (positive)
Universal Emotions, 6 emotions
(Ekman) happiness fear anger disgust sadness surprise
Dimensions of Emotion
Valence
Avoidance (negative) vs Approach (positive)
guilt . want
Arousal
intensity
Measures of emotions
Direct
self-report manipulation
expresssion facial expression
Indirect
Galvanic skin response - GSR or SCR
Emotional stroop task
Pupil dilation
Schachter experiment
attribution of emotion
Emotion = arousal + attribution
interpretation/attribution to stimulus
emotion = construction
when an emotion is felt, a physiological arousal occurs and the person uses the immediate environment to search for emotional cues to label the physiological arousal
Injected with epineprine or placebo
participants who had no explanation of why their body felt as it did, were more susceptible to the confederate.
Dutton & Aron shaky bridge experiment
misattribution of emotion
natural setting that would induce physiological arousal
because they had transferred (misattributed) their arousal from fear or anxiety on the suspension bridge to higher levels of sexual feeling towards the female experimenter
Facial Feedback Theory
facial movement can influence emotional experience
ex: an individual who is forced to smile during a social event will actually come to find the event more of an enjoyable experience
Stunted feedback: Botox vs Restylane
Botox: kills nerve - and feedback
Restylane: just a filler - leaves feedback intact)
Botox injected participants report less emotion in response to pleasant and unpleasant films after procedure
Orbitofrontal cortex
behavioral deficit
explicit knowledge of appropriate behavior is intact
Phineas Gage
emotional, frequent outbursts of anger, rage, couldn’t inhibit inappropriate behavior
1843‘Gage was no longer Gage’
damage to orbitofrontal cortex
knowing v. doing
Utilization behavior
utilization behavior: use a stimulus in sight even when inappropriate
automatic reaction to stimuli
syringe - diabetic
contextually inappropriate behavior
ask v. knowing
Emotional Detachment
Pts can describe their actions but show EMOTIONAL DETACHMENT from consequences
OVERPRAISING
not sensitive to contexual feedback
Knowing vs Doing - behavior is off but patients still ‘know’ what is appropriate
(e.g. over-praising task and generating nicknames task)
watch video and know it’s weird
Amygdala
Lesioned responses
Emotional memory
sumbliminal matches
Agnes
no outward signs of emotion
no facial expression
no feelings toward other people
felt empty, zombie-like
Other patients lose prosody = emotional component of speech
damage to OFC
Agnes
no outward signs of emotion
no facial expression
no feelings toward other people
felt empty, zombie-like
Other patients lose prosody = emotional component of speech
damage to OFC
SCR: OFC v. Control
SCR: skin conductance response; measures sweat gland activity; indicator of arousal
NEUTRAL/FLAT IN OFC PATIENTS
Conditioned-fear respose
skin response to emotionally scary stimulus
Conditioned Fear Response
(classical conditioning)
shock (US)
rat shows fear/startle response (UR)
pair shock (US)+light (CS), rat learns association,
light alone (CS) elicits fear/startle (CR)
Amygdala lesions impair fear conditioning in animals and humans
Fear memory
physiological response
vs. declarative memory - what is going to happen
