MemoryRef: Banich Ch. 10, 323-363.

Test 1• Marks will be out today (noticeboard and website)

• Papers will be returned in your labs

Results: class average 67%Results: class average 67%

CC 7%7%

C+C+ 15%15%

B-B- 18%18%

BB 16%16%

B+B+ 11%11%

A-A- 8%8%

AA 8%8%

A+A+ 8%8%

Test 1• Double-check the arithmetic on your paper (mistakes can

happen1)

• Queries about grading are welcome

• Model answers will be posted late today

• Did worse than you expected? Come and see me or one of the tutors NOW. Maybe we can help for next time….

MemoryRef: Banich Ch. 9, pp. 315-339, 343-

354, 356-361

Memory: Brain Regions• Many brain regions involved in memory

• BUT one network of structures has special role:

• Medial temporal lobeMedial temporal lobe

• HippocampusHippocampus

• ThalamusThalamus

• Hypothalamus Hypothalamus (mammillary bodies)(mammillary bodies)

Medial Temporal SystemMedial Temporal System

The Medial Temporal System

• Common causes: brain injury, infection, also some degenerative diseases (Alzheimer's, Korsakoff's)

HM: "He could no longer recognise the hospital staff, apart from HM: "He could no longer recognise the hospital staff, apart from

Dr. Scoville himself, who he had known for many years; he did not Dr. Scoville himself, who he had known for many years; he did not

remember and could not relearn the way to the bathroom, and he remember and could not relearn the way to the bathroom, and he

seemed to retain nothing of the day-to-day happenings in the seemed to retain nothing of the day-to-day happenings in the

hospital... A year later, HM had not yet learned the new address, hospital... A year later, HM had not yet learned the new address,

nor could he be trusted to find his way home alone... He is unable nor could he be trusted to find his way home alone... He is unable

to learn where objects constantly in use are kept”to learn where objects constantly in use are kept”

Can see what it does by examining P's with damageCan see what it does by examining P's with damage

Two Components to Amnesia

Affects facts/events both before and after illness:

Retrograde amnesia: loss of things learnt before illness

Anterograde amnesia: loss of new facts/events

Onset of illness

Retrograde Amnesia Anterograde Amnesia

Before illness After illness

Time

Retrograde Amnesia: Features

Shows "temporal gradient":

Laurel: "When I came out of the coma, I thought I was 13 Laurel: "When I came out of the coma, I thought I was 13

years old, and I was actually 26. I didn't remember I was years old, and I was actually 26. I didn't remember I was

married; I didn't remember a whole ream of things.”married; I didn't remember a whole ream of things.”

• PZ's recall of autobiography:

olderolder newernewer

Age of memoryAge of memory

Am

ou

nt

reca

lled

Am

ou

nt

reca

lled

Retrograde Amnesia: Features

Ways of Testing:Ways of Testing:

• Events questionnaires with items from diff. periodsEvents questionnaires with items from diff. periodse.g.e.g. What British scientist was imprisoned for telling theWhat British scientist was imprisoned for telling the

Russians how to make the atomic bomb?Russians how to make the atomic bomb?

• Famous Faces TestsFamous Faces Tests

Retrograde Amnesia: Features

Laurel: "Often I find myself saying things I didn't know that I knew.

It's almost like a third person relaying the information, which to me

is fascinating. It made me realise that all of that information is not

lost. It's still there.”

Shrinks gradually with recovery over time

Medial Temporal System involved in retrieval Medial Temporal System involved in retrieval

of existing memories - at least recent onesof existing memories - at least recent ones

Retrograde Amnesia: Features

Two Components to Amnesia

Affects facts/events both before and after illness:

Retrograde amnesia: loss of things learnt before illness

Anterograde amnesia: loss of new facts/events

Onset of illness

Retrograde Amnesia Anterograde Amnesia

Before illness After illness

Time

Anterograde Amnesia: Features

• Knowledge and personal history are "frozen in time”

• P may be unable to recall events from 5 min before:

HM: "… every day is alone in itself; whatever enjoyment HM: "… every day is alone in itself; whatever enjoyment

I’ve had and whatever sorrow I’ve had. Right now, I’m I’ve had and whatever sorrow I’ve had. Right now, I’m

wondering ‘Have I done or said anything amiss?’ You see, wondering ‘Have I done or said anything amiss?’ You see,

at this moment everything looks clear to me, but what at this moment everything looks clear to me, but what

happened just before? That’s what worries me. Its like happened just before? That’s what worries me. Its like

waking from a dream; I just don’t rememberwaking from a dream; I just don’t remember

• Not specific to any modality

Anterograde Amnesia: Features

System deals with all info. regardless of sourceSystem deals with all info. regardless of source

• Affects facts as well as eventAffects facts as well as evente.g. e.g. new vocab: jacuzzi, granolanew vocab: jacuzzi, granola

current affairscurrent affairs

Deals with both Episodic and Semantic memoriesDeals with both Episodic and Semantic memories

• Short Term Memory not affected

• Amnesics perform normally at this:

Anterograde Amnesia: Features

Repeat the following sequence:

3 9 1 7 8 5

System involved only in Long Term MemorySystem involved only in Long Term Memory

• Skill learning spared e.g. learning piano piece

mirror tracing

Anterograde Amnesia: Features

System does not deal with System does not deal with Procedural LearningProcedural Learning, ,

only only Declarative KnowledgeDeclarative Knowledge (Cohen et al) (Cohen et al)

• Certain types of “implicit” learning also

spared: e.g. Repetition Priming

Word stem

completion

Anterograde Amnesia: Features

Repetition Priming (Gollin pictures):

Anterograde Amnesia: Features

• P will choose "motel" rather than "motorcycle”

• No recollection of ever having done the task before!

Word-stem completion:Word-stem completion:

Anterograde Amnesia: Features

Study these words e.g. motel cyclone

Report first word that comes to mind:

mot_______

DELAY

Spared memory not limited to motor skills, but can also include cognitive tasks

Anterograde Amnesia: Features

Some authors prefer terms Explicit vs. Implicit Some authors prefer terms Explicit vs. Implicit memorymemory

Conclusions about Medial Temporal System

• Helps form new long-term memories (but not STM)

• Also helps retrieve recently-acquired memories

• Deals with both episodic and semantic memory

• Deals with explicit memories only; implicit memory, incl. skill learning, not affected

• Does not store memories, but rather is involved in encoding/retrieval of memories stored elsewhere

Current View

• Actual content of memories is distributed throughout cortex (exact area depends on type of info.)

• Medial Temporal System ties together the various components of a memory

• With time, rest of cortex can learn to tie together the components without going thru this system

Other Systems Involved in Memory

• All areas of cortex involved, because all are capable of

"learning" in their own domain

e.g.new skills: cerebellum

word-stem completion: posterior language areas

• Two Especially Important Regions

– Left parietal lobe: Short-term Memory (STM)

– Frontal lobes: Working Memory, Source Memory

Left Parietal Lobe: STM• Short term storage of verbal information e.g. digit span task

After a mild stroke, JK made a good physical recovery, and some After a mild stroke, JK made a good physical recovery, and some months later, was able to return to his previous, demanding position as months later, was able to return to his previous, demanding position as a private secretary in a large corporation. He had little difficulty a private secretary in a large corporation. He had little difficulty resuming his former duties: he was able to remember which resuming his former duties: he was able to remember which tasks/clients he had worked with just before his illness, and had no tasks/clients he had worked with just before his illness, and had no problem learning new tasks and remembering new clients. However, he problem learning new tasks and remembering new clients. However, he noticed a sudden difficulty with numbers. He found himself unable to noticed a sudden difficulty with numbers. He found himself unable to accurately record numerical information given to him verbally. Also, accurately record numerical information given to him verbally. Also, when dialling phone numbers, he could still deal with familiar numbers, when dialling phone numbers, he could still deal with familiar numbers, but would repeatedly make mistakes when dialling a new number for but would repeatedly make mistakes when dialling a new number for the first time.the first time.JK underwent further neuropsychological tests which revealed that he JK underwent further neuropsychological tests which revealed that he had a digit span of only one!had a digit span of only one!

Left Parietal Lobe: STM

• STM helps maintain auditory-verbal information

• Is one of several resources we use to maintain information temporarily

• Current view: STM (or “phonological store”) a slave system of Working Memory….

Frontal lobes: Working Memory

Working Memory:

• “Smart” system that keeps info. on-line while a task is performed

• relies on more passive stores like STM, as well as other storage systems

e.g. Baddeley’s model:e.g. Baddeley’s model: Visuospatial scratch pad

Phonological Store

Central Executive

• Central ExecutiveCentral Executive (the “smart” part of Working (the “smart” part of Working Memory) is located in frontal lobesMemory) is located in frontal lobes

Frontal lobes: Working Memory

Visuospatial scratch pad

Phonological Store

Central Executive

Food

No

food

Delay (1-10sec)

Food placed

in one bowl

Bowls covered

S must choose

correct bowl

Evidence: Monkeys with prefrontal lesions:Evidence: Monkeys with prefrontal lesions:

Frontal lobes: Working Memory

Frontal lobes: Source Memory

• Temporal relationships between events:

?

Which was most recent?

P’s can't judge temporal relationships, but can

recognise previous experiences:

Frontal lobes: Source Memory

?

Which did you see?