Together activate LTD when mossy and climbing fibers work together
UR + CR
Interpositus => red nucleus => cranial motor nuclei=> blink ( UR + CR).
Conditioned response goes away when paired stimulus is unpaired
Vital for tone + puff learning. Without it rabbits showed extinction when conditioned stimulus is still paired.
Memories need some time before becoming fixed
Temporal retrograde amnesia
Usually due to trauma. Cannot recall information prior to traumatic event
Cannot recall information following trauma.
PET scan study of tone+puff
1) tone/puff unpaired
2) tone+puff paired
3) test with subtraction logic
Conclusion: people with cerebellum damage don�t learn reflex as well
Random image pairing. Initially 1 neuron only cares about 1 image. After pairing 1 neuron cares about 2 images.
Studied the ventral visual stream. STM vision and LTM storage
Model on storing declarative memory
STM from neocortex=> hippocampus=> LTM in neocortex
Somatosensory cortex has plastic neurons due to experiences
Homunculus aka brain real estate for sensory info
Does the auditory cortex learn?
Experiment does tuning curve of an auditory cell shift.
1) find cell of best frequency
2) Pavlovian conditioning: foot shock paired with neighboring frequencies
3) find cell again
Auditory cells are tuned to a specific frequency and best respond to one frequency
Old philosophy on senses
Sensory cortex couldn�t learn because basic sensory function doesn�t change
Shift in tuning curve
Shift does appear with conditioning. However hippocampus vital for recall. Tuning curve will unshift the next day if hippocampus is destroyed.
Muscle memory and habit
Packard and McGaugh
Visual vs spatial discrimination
1) see ball get on ball at fixed spot
2) go to same spot with hidden ball
3) go to seen ball in new spot
Results: control goes to new ball. No hippocampus goes to new ball. No striatum go to hidden ball.
McDonald and White
Triple Disociation Test
Focused on the striatum, hippocampus, and amygdala.
Showed triple disociation with rats in a radial maze given various training
Squire Weather Prediction task
1) set of cards correlate with sun or rain. Cards not perfect correlation but probability.
2) not conscious learning, not declarative memory recall
3) stimulus and response learning
Weather Prediction Results
Parkinson�s = no SR learning
HM/ CAS = normal learning
When asked about test after
Parkinson�s = normal recall
HM/ CAS = fail to recall
Shows double dissociation!
Figure 10.5 kermandi and Joseph
Monkeys trained on specific sequences of light
SR learning: specific sequence of light = get juice
Cell responds to L light only after U light appears
Cell responds to particular part of sequence
Cells in striatum respond to robot SR
Skill learning, priming, and conditioning aka nonconscious learning
Muscle memory mostly in basal ganglia, motor cortex, and cerebellum
Cued recalling of an earlier exposure
Sensory cues like vision and perception works mostly in frontal lobe
Stimulus recalls past thought reduces activity in frontal lobe
Simple delay and trace conditioning
CS is brief and followed by a blank "trace" period then the US.
Hippocampus and neocortex dependent
Simple delayed conditioning
Standard CS and US pairing
Classic amnesia syndrome = HM amnesia
Can answer primed word completion test but not word recall tests
Medical temporal lobe = no good for priming
Neocortex = good for priming
Visual cortex damage = Missing sight
Tested for priming
Declarative memory = fine
Priming ability = poor
Priming test or MS
1) show words list a
2) show new words list b
Priming = less active sensory cortex = more faster recognition = more efficient and less energy
Muella and Pilzecker
Students of Ebbinghaus
2 word list study
Learning list 2 interrupted learning of list 1
More time in-between learning two lists = less interruption of learning
Cereletti and bini
1938 first to discover electroconvulsive shock
Electroconvulsive shock still used today for treatment of depression
1949 light+shock in one compartment. Other side safe. Rat learns active avoidance to avoid shock.
ECS in rats
Takes about 1 hr for memory consolidation in rats. Rats with ECS don�t learn shock avoidance well. ECS has an effect like retrograde amnesia
McGaugh and Gold
Why is retrograde amnesia as loss of recent memory first?
Temporally graded memory loss occurs becuase consolidation is interrupted by truamatic event.
Memory gradient graph
Retrograde enhancement gradient: new memories = more malleable.
Retrograde amnesia gradient: new memory = less malleable
Temporally graded retrograde amnesia
Info gained immediately before trauma is lost, but info gained longer ago is retained.
Retrograde enhancement gradient
After trauma the enhancement of memory decreases as time goes on
Retrograde amnesia gradient
After trauma new memories are most susceptible to loss.
Retrograde enhancement and retrograde amnesia
Explains why there is both retrograde amnesia and anterograde amnesia in patients suffering from head trauma.
Trauma hinders both memory storage and memory recall
McGaugh learning/ performance distinction
At the time the status quo: drug=> train/ learn=> wait => test (no distinction)
Train/ learn => drugs => wait => test. Creates distinction because drugs don�t effect learning or recall phase, only consolidation phase
Rat poison used in a really small dose to enhance memory
McGaugh discovered the right drug at right dose enhances memory and performance. Too little or too much drug inhibits memory/ performance
Best memory enhancing drugs?
Stimulants = amphetamines = catechamines = fight or flight hormones in adrenal glands.
What is the body's natural amphetamine?
Adrenal hormone = adrenaline and Norepinephrine ( in brain)
Why does body accept morphine?
An endogenous morphine naturally exists in body
Morphine and memory
Soldiers given morphine within two hrs of injury are less likely to get PTSD
Opiate used to numb severe pain by acting in the central nervous system
Post traumatic stress disorder an extremely painful memory never goes away and inhibits daily life.
How do amphetamines or adrenaline enhance memory?
1) adrenaline activates the vagus nerve
2) adrenaline and glucose work together to activate the amygdala
Flight or fight response
Triggered by stressful situation. Stress activates adrenal glands. Adrenaline goes through blood stream to vagus nerve. In the brain Norepinephrine also activates vagus nerve. Vagus nerve regulates heart rate.
Adds lots of glucose into the blood stream during stress. Body uses sugar to run or fight.
Nucleus of the solitary tract
Aka nucleus tractus solitarii
Connects the vagus nerve in the medulla to the amygdala
Numbing drug which renders part of the brain useless
Is the NTS vital for emotional memory?
Yes. Test with lidocaine in NTS => train/ learn=> drug = memory loss ( in rats with enhanced memory
No NTS = No Memory enhancement
NTS activated by Norepinephrine. Norepinephrine stimulates the brain to enhance memory. No NTS = regular memory
Inhibits Norepinephrine receptors. Blocks memory enhancing effect of Norepinephrine
MODULATES memory can either enhance or hinder
Test amygdala and memory
Legion amygdala=> train=> induce adrenaline=> record = no memory enhancement.
Measure amount of Norepinephrine present in amygdala
Intverted U relationship for memory and dose
McGaugh more Norepinephrine
Shock chamber and 24 hr recall. More Norepinephrine = longer reenter time
Does the amygdala store emotional memory?
No. Amygdala only modulates another system
1985 McGaugh declarative memory system
Normal people remember emotional info more than neutral info. Propranolol inhibits amygdala, Propranolol subjects have almost no preference.
Cahill PET scan and amygdala
Experiment: watch=> wait 3 weeks=> test memory
Watch 2 films while in pet scan. ( men only) more glucose in amygdala = better recall