It’s a Boy!

Where does the dissociation between structures involved in LTM come from (in humans)?

Long-term Memory

Long-term Memory

Patient H.M.• “Loss of Recent Memory After Bilateral Hippocampal

Lesions”, Scoville and Milner (1957) • onset of epilepsy at age ten, perhaps due to bike

accident (wear a helmet!)

• 1953 - underwent temporal lobectomy to reduce seizure activity

• severe anterograde amnesia• temporally graded retrograde amnesia

Patient H.M.

Patient H.M.

1. Memory and perceptual skills are dissociable.2. Lesions of the MTL produce amnesia for recent but not

remote events.3. There are multiple long-term memory systems in the brain.

Patient H.M.

Long-term Memory

• What’s the one thing that all of these people have in common?

Lesions!

Long-term Memory• What about normal memory?

• That is, memory in the “normal” brain

Long-term MemoryThe theory is that the MTL is temporally involved in declarative memory in normal humans…

Long-term Memory

Long-term Memory

Long-term Memory• functional imaging data from “normal” subjects confirms

lesion studies

• be skeptical!

Long-term Memory• What would it be like to possess the ability to remember

everything?

Long-term Memory• Case study of S. (Solomon Shereshevskii)

• Russian journalist

• never took any notes, recalled everything verbatim

• thought this was “normal”

Long-term Memory• Alexander Luria - Soviet neuropsychologist

Long-term Memory• Shereshevskii suffered from synaesthesia• stimulation of one sense leads to automatic stimulation

of another • hearing a sound produces a visual experience

“I can see the music…”

Long-term Memory• random number table

Long-term Memory

1 this is a proud, well-built man 2 is a high-spirited woman 3 is a gloomy person6 is a man with a swollen foot7 is a man with a moustache 8 is a very stout woman - a sack within a sack.

“As for the number 87, what I see is a fat woman and a man twirling his moustache”

Long-term Memory• memory consists of associative networks• perhaps mnemonists can create better networks

To Kill A Mockingbird

Long-term Memory• memory consists of associative networks• perhaps mnemonists can create better networks

To Kill A Mockingbird

highschoolMr. Lacey

English

Long-term Memory• memory consists of associative networks• perhaps mnemonists can create better networks

birdcanary

chicken

mockingbird

To Kill A Mockingbird

racism

highschool

Martin Luther King

skiing

Mr. Lacey

English

• What do you think the brain of someone that has this “super memory” would look like?

Long-term Memory

• What if I told you it looked like this?

Long-term Memory

Kim Peek

Long-term Memory• macroencephaly• no corpus callosum• no anterior/posterior commisure

• degenerated cerebellum

• Autism?• Motor disturbances• Overall I.Q. of 87

• despite this, he displays some amazing abilities…

Long-term Memory

Long-term Memory

Long-term Memory

http://www.youtube.com/watch?v=k2T45r5G3kA

Long-term Memory• 98% retention rate for reading material• reads on average 8 books a day (has approximately 9000

memorized!)• one page every 8-10 seconds• also has incredible memory for music, often remembering

compositions only experienced once

Long-term MemoryWhat could support this ability?

“Does brain damage stimulate compensatorydevelopment in some other area of the brain, or does it

simply allow otherwise latent abilities to emerge?”

Long-term Memory