MEMORY

Dimensions of behavior

• COGNITION : information handling aspect of the behavior.

• EMOTIONALITY : concerns feelings and emotions

• EXECUTIVE FUNCTIONS : related to ‘how behavior is

expressed’

Cognition

1.Receptive functions – acquire new information

2.Memory and learning – storage & retrieval

3.Thinking – reorganize the information

4.Expressive function – means through which information is communicated.

•Characteristic Sx.•Measureable .•Subtle changes can be identified.

•Characteristic Sx.•Measureable .•Subtle changes can be identified.

• What is memory ?

• Types of memory

• Understanding memory – anatomical and physiological basis

• How to evaluate memory ?

• What are its clinical implications ?

Definition of memory

“Mental process that allows the individual to store information for later recall.”

Three temporal stages of memory i. Immediate memory – seconds ii.Recent memory – minutes to daysiii.Remote memory – years

Memory systems Short term memory Working memory Long term memory Declarative memory Non declarative memory

• What is memory ?

• Types of memory

• Understanding memory – anatomical and physiological basis

• How to evaluate memory ?

• What are its clinical implications ?

Long term memory

Medial temporal lobe & hippocampus

•Emotional response -- amygdyla

•Skeletal muscle -- cerebellum

•Emotional response -- amygdyla

•Skeletal muscle -- cerebellum

Habituation and

Sensitization

reflex pathways.

Habituation and

Sensitization

reflex pathways.

Neocortex Neocortex Striatum

Explict memory ( non declarative memory )

• Factual knowledge of people, places, things and meaning of facts

• Conscious process and recall requires conscious search of memory.

• Expressed mainly in verbal form

1. Episodic - events and personal experience

2. Semantic - memory for facts

Implict memory ( declarative memory )

• Involved in training reflexive motor or perceptual skills.

• Builds up slowly through repetition over many trails

• Recalled unconsciously

• Expressed mainly in form of performance

• What is memory ?

• Types of memory

• Understanding memory – anatomical and physiological basis

• How to evaluate memory ?

• What are its clinical implications ?

H.M patient ( Henry molaison)• Case of temporal lobe epilepsy Medial temporal lobes , hippocampus and

amygdyla were removed bilaterally.

• He had – * normal STM * normal LTM (events before operation) * good language and IQ was normal but he was unable to retain information for > mins

, mainly about people , places and objects.

He lost the ability to transfer new data from STM to LTM

extensive bil. lesions of limbic ass. areas of medial temporal lobe show this defect. (i.e in explict memory)

Understanding memory Three basic questions• How does information get into

memory?

• How is information maintained in memory?

• How is information pulled back out of memory?

Stages of memory process :1.Reception and registration2.Storage and retention3.Recall and retrival

Anatomical basis

Memory process

• Information is first acquired through unimodal and polymodal association areas – prefrontal,limbic and parieto-occipito-temporal cortex – which synthesize visual and somatic information

Memory process

• Therefore entorhinal cortex have dual functions – both input and output.

# damage causes severe memory loss and all sensory modalities involved.

# earliest pathological change in AD – entorhinal cortex involvement and so explict memory lost early.

• Hippocampus – right side – spatial memories stored

(lesions cause defect in spatial orientation) left side – memories for words,

objects and people (lesions cause defect in verbal memory)

Anatomical basis

• Hippocampus is only a temporary way station for LTM.

• Unimodal and polymodal association areas of cortex are concerned with LTM storage.

• Amygdyla – stores component of memory concerned with emotion. It doesn't store factual information.

(damage has no effect on explict memory)

Association areas are the ‘ultimate repositories’

Association areas are the ‘ultimate repositories’

• In hippocampus , it takes days-wks to facilitate storage of information about the face initially processed by ass. areas.

• There is relatively slow addition of information to neocortex, which permits new data to get stored without disrupting information.

Their (ie ass. areas) damage l/t impaired recall of knowledge , aquired before the damage. Ex- prosopagnosia.

Implict memory

• Introduction • Different forms of implict memory are

aquired through different forms of learning and involve different regions.

Acquired through fear – amygdyla (emotional)

Acquired through operant conditioning – striatum and cerebellum.

Acquired through sensitisation and habituation – sensory and motor systems.

Types of learning

1. Non associative learning : learns about properties of single stimulus

Habituation – dec response to stimulus, when presented repeatedly. Ex.-crackers.

Sensitization – enhanced response to any stimuli , following a first intense stimulus.

this occurs through reflex pathways.

2. Associative learning : Operant conditioning (Skinner) –

involves relationship b/w behavior and consequence of that behavior. Ex.- Reward .

Classical conditioning (Pavlov) – involves relationship b/w two stimuli.

PRIMING : effect in which exposure to a stimulus influences response to a later stimulus. Ex- Table- ‘tab__’

Learning driving

Involves conscious execution (explict) of specific seq of motor acts necessary to drive .

with experience driving becomes automatic and non conscious (implict) activity

• What is memory ?

• Types of memory

• Understanding memory – anatomical and physiological basis

• How to evaluate memory ?

• What are its clinical implications ?

EVALUATION OF MEMORY

• Assess type of memory deficit.• Degree of memory loss.• Impact of memory loss on patients

functional ability

• Accurate assessment of memory requires that any question asked by examiner be verifiable from a source, other than pt.

• Historic events are commonly used by the examiners to screen both recent and remote memory .

But it requires pt.’s premorbid intellectual capacity & social exposure.

• Most valid and sensitive test for recent memory –

learning new material and

recalling it over time.

• Hinders to the test are – > inattention . > disturbances of basic

sensory, motor and language functions.

• Any evidence of aphasia impairs both verbal STM and LTM. Caution to be taken while examining these pts.

• “Valid memory testing presumes that the patient is reasonably attentive , can relate to and cooperate with the examiner , and has no defect that impairs language comprehension and expression.”

( Poor memory performance in pts who

are deaf, aphasic , acute confusion, psychotic, depressed and inattentive – reflects defect caused by the process alone )

IMMEDIATE RECALL / STM

Tested by digit repetition.• Repeat digits at rate of one per second. *Normal person repeats five to seven digits. *< five digits – impaired repitition.

3-7 2-4-9 8-5-2-7 2-9-6-8-3 5-7-1-9-4-6 8-1-5-9-3-6-2

RECENT MEMORY (ORIENTATION)

• Ask the Q. in sequence.

1. PERSON Name Age Birth date

2. PLACE Location City Home

address

3. TIME

Date Day of the week. Time of the day Season of the

year Duration of time

with the examiner.

• Normal people usually perform well , some time with less scores in ‘time orientation’

failed items are usually date of month and day of week .( mainly illiterates)

• Orientation to time and place are actually measures of recent memory, as they test the pts ability to learn these changing facts

REMOTE MEMORY• Evaluated by pts ability to recall personal events

and historic events.

Normal and those with mild nonspecific brain damage do with same accuracy. Impaired perfor- mance is pathologic.

PERSONAL INFORMATION Where were you born? School information Vocational history Family information

• Normal person tells with out difficulty• If pt has no memory of these events,

this implies deficient memory. ( some Q. depend on

literacy level of pts )

HISTORIC FACTS

Four CM s during your lifetime Last elections

NEW LEARNING ABILITY

• This is to assess pts ability to actively learn new material ( to acquire new memories)

• All stages of memory process __ are necessary for adequate performance.

Any defect at any stage l/t loss of this ability.

FOUR UNRELATED WORDS• Tell that “I am going to tell u 4 words that

u have to remember. In a few minutes, u have to recall these

words

• Ask him to repeat the words after they are presented- to ensure that he understood.

• After 5 min , ask him to recall the words

• Ex) Fun – carrot – knee – honesty Red – happiness – brush – grapes

• Normal pt < 60 yrs accurately recalls three or four words after 10 min delay.

pt > 80 yrs recalls two words normally after 5 min delay.

• If he cannot recall , 1. cues – semantic (‘one word is color’) phonemic (‘hap… for happy’) 2. ask to select from a series of words. When 2 yeilds better than 1(recall), the problem may be due to retrieval defect,

rather than storage. This indicates normal implict memory.

VERBAL STORY FOR IMMEDIATE RECALL

• Tell the pt “ I am going to read a short story and I want u to remember,

and I want u to tell me what I have told ”

• Read the story slowly and correctly without any pauses.

• Ask the pt to retell the story as accurately as possible.

It was july / ramu had packed up / their four children / and were off on vacation .

They were taking / their yearly trip / to the beach / of vizag.

This year / they were making / a one day stop / at araku.

After a long day drive / they came back to hotel / and found that / they had left / their suit cases / in the garden.

• No. of correct memories _________• Describe confabulations , if present.

• Of these 20 separate ideas, a normal person of < 70 yrs should be expected to produce atleast 10 items

• This is a sensitive method of assessing short term verbal recall.

• Story recall discriminates b/w Normal and AD pts Brain damaged and low IQ pts

VISUAL MEMORY (Hidden objects)

• Tested in all pts, but mainly useful in aphasic pts. and also for illiterates.

• Tell the pt that you are going to hide some objects and ask him to remember where they are.

• Hide 4 or 5 common objects like – keys, pen, etc in various areas of pt’s sight.

• After 5 min , ask pt to find the objects.• Ask him to name the objects that he

could not find.

Assess by following Q.

• Number of hidden objects found.• Number of hidden objects named, but not

found.• Number of hidden locations found, but

objects not named.

Normal person < 60 yrs finds 4 or 5 objects.

Impaired visual memory – finds < 3 objects.

Aphasic pt should find the objects , but may not be able to name them.

PAIRED ASSOCIATE LEARNING

• Another highly sensitive measure of new-learning ability.

• Tell the pt that you are going to read a list of words – two at a time .

• Pt is expected to remember the two paired words. ( ex. High – Low )

• Read the 1st presentation list and test for recall by saying 1st recall list .

(Give the first word of pair – ask for other)

• Correct the incorrect responses , if any.• After 10 sec, give 2nd presentation and

recall lists. 1ST PRESENTATION

LIST

Weather - box High - low

House - incomeBook – page

1st RECALL LIST

House - ______High - ____

Weather - _______Book - ____

2nd PRESENTATION LIST

House - incomeBook – page

Weather - box High - low

2nd RECALL LIST

High - ____House - ______

Book - ____Weather - _______

• No. of easy paired associates recalled : • No. of difficult paired associated

recalled :

• Normal pt < 70yrs – recalls two easily paired associates and atleast one hard on 1st recall

and to recall all on 2nd trail.

• Total PAL score is the best measure of verbal learning.

• What is memory ?

• Types of memory

• Understanding memory – anatomical and physiological basis

• How to evaluate memory ?

• What are its clinical implications ?

CLINICAL IMPLICATIONS

• Limbic structures are involved in LTS and retrieval of recent information.

• Structures required for immediate recall and remote memory are not yet established.

IMMEDIATE RECALL • Performed by language cortex surrounded by

sylvian fissure. (it requires registration, short term holding

and repetition, doesn’t require LTS) Mechanism is not known. May be due

to ? Reverberating circuits ? Cortical after images

• STM is a property of cortical sensory, motor

and integrative areas. If these basic sensory – motor areas are

damaged , STM is disrupted.

• Most common cause for failure of tests - inattention.

• Inattention may be – organic - confusional states. - dementia. functional – anxiety and depression• Pt. with dementia have difficulty with

immediate memory due to – > inattentiveness > cortical ( sensorimotor) atrophy > intellectual detriment.

Recent memory

• Limbic structures – Medial temporal lobe Mamillary bodies Dorsal medial nuclei of thalamus

are essential subcortical links in storage

and retrieval of both verbal and non verbal memories

• Bilateral temporal damage Damage to phc and entorhinal cortex Orbitofrontal lobe damage (AcA

aneurysm rupture) -- impair recent memory.

• In damage of these structures, # anterograde amnesia & # retrograde amnesia occurs. i.e pt. is fixed in time

ISOLATED LIMBIC SYSTEM DAMAGE – organic amnestic

state. Severe anterograde amnesia Moderate to severe retrograde amnesia Confabulation Intact immediate memory No change in premorbid levels of intellegence. They don’t remember time , place , person.Causes : bil. Hippocampal lobectomy

HSV encephalitis

bil. Hippocampal infarction.

korsakoff syndrome. vasc or traumatic lesions of DMN of thalamus

POST HEAD INJURY –

Some retrograde amnesia Transient anterograde amnesiaMech. - temporal lobes are concussed againest

bony confines of middle cranial fossa , which causes disruption of hippocampal function.

Post traumatic amnesia is usually reversible, if significant it is permanent.

In boxers (dementia pugilistica),gradual but permanent memory disturbances occur.

In head injury, ‘shrinking retrograde amnesia’ occurs. i.e retrograde amnestic period shortens in days following recovery of consiousness.

initially pt doesn’t recall yrs preceding RTA . With in days, pt remembers all but few minutes preceding RTA.

ALZHEIMER’S DISEASE – Defect in new learning

KORSAKOFF’S SYNDROME

• Thalamus and mamillary body damage occurs.

Recent memory lost Good implict memory

• Deficit in retrieving the information , and not in storage.

In cortical process memory traces are stored without pt awareness.

Implict memory is retained which don’t need active recall. Even then it doesn’t help him – as he doesn’t realize that they are stored.

(In hippocampal + temporal lobe damage, both storage and retrieval are defective.)

TRANSIENT GLOBAL AMNESIA

• Transient ischemia of both medial temporal lobes secondary to decreased perfusion in PCA territory.

Acute , but temporary confusional state. Amnesia . Disoriented to time , place. Significant defect in new learning ability.

• Recovers in hrs-days, but left with permenant amnesia for the episode itself.

OTHERS• Bilateral lesions of hippocampus – infarctions

– permanent memory loss.• Unilateral lesions – dominant temporal lobectomy – verbal

learning non dominant temporal lobectomy -

defective visual learning.

• Drugs : Psychotropics B-blockers Prednisolone AED Medications and toxins- alcohol

REMOTE MEMORY • Older memories stored in association

cortex and these doesn’t require limbic system for retrival from storage.

• Seen in Alzheimer’s disease and Pick’s disease (atrophic dementias)

• In koraskoff psychosis and bil temporal lobectomy,

remote memory retained. recent memory lost.

ALZHEIMER’S DEMENTIA

• Difficulty with STM - atrophy of basic sensory association cortex.

• Decreased recent memory acquisition – degeneration of hippocampus

• Defect in remote memory – widespread cortical atrophy.

FUNCTIONAL MEMORY DISTRUBANCES

• First and most common psychiatric condition with memory disturbance is DISSOCIATIVE STATE (now, psychogenic amnesia) .

1.Dissociative amnesia or fugue : pts lose their identity and travel to new location.

2.Dissociative state or localized amnesia: pt have periods of hrs to days when thay carry out normal routine life and become aware that they remember nothing during this period.

• During these states, pts are not confused (as seen with TGA). able to learn new material (unlike those in

organic amnesia).

3. Ganser’s syndrome : syndrome of approximate answers. Pt routinely give approx. answers as if thay

have knowledge regarding the Q. These pts have clouded consciousness ,

hallucinations and conversion Sx.

• Ganser’s syndrome seen in – Prisoners Schizophrenia Brain Disease. Malingering.4. Malingering : pts may give approx answers ,

memory loss is inconsistent , fail all memory tests, but remembers football score of past week.

TAKE HOME MESSAGE • Information must first get registered in basic

sensory cortical area and then processed through limbic system for new learning to occur. Finally memory is established in appr. association cortex.

• Immediate recall lost – pri. sensory / motor cortex. Learning – hippocampus / DMN of thalamus. Old remote memories – widespread cortex . • Careful testing is important for clinical and

anatomical diagnosis

Thank you