Psyco

INTRODUCTION TO

PSYCHOLOGY

CLASS #7

Dr. Charles-Etienne Benoit

Today’s Lecture

 Sensory memory

 Short-term memory

 Long-term memory

 Forgetting

 Amnesia

 Biology of memory

Inspired memories

Zeus and Mnemosyne (Memory) in the Greek mythology were the parents of the

Muses, the guiding spirits of the Nine Arts.

What is memory?

 An internal record or representation of some prior event or experience.

 A set of mental processes that receives, encodes, stores, organizes,

alters and retrieves information over time.

 It is a constructive process.

It can be excellent as shown by Franco Magnani painting which

were done from memonies, he was named the memory artist.

Information processing model

Mental processes

 A model of memory in which information must pass through discrete stages

via the processes of encoding, storage, and retrieval.

 Encoding: Transforming information into a form that can be entered and

retained in the memory system.

 Storage: Retaining information in memory so that it can be used at a later time.

 Retrieval: Recovering information stored in memory so that we are consciously

aware of it.

Sensory memory

 Its function is to process basic physical characteristics

 It can hold many items at once for a very brief retention.

 Duration depends on the sense involved

 0.3 seconds for visual information

 2 seconds for auditory information

 All senses have a sensory memory

 Iconic memory (visual information)

 Echoic memory (auditory information)

 Sensory memory holds a large amount of information, far more than ever

reaches consciousness.

 Attention is needed to transfer information to working memory

Short-term memory

 Short-Term Memory, also known as working memory is the temporary

storage of sensory information that filter whether to send it on to

long-term memory or forgotten.

 It can hold 5-9 items for about 30 seconds before they are forgotten.

 Duration and capacity can be increased with maintenance rehearsal

and/or chunking

 Sensory memories lasts just long enough

to dissolve into the next one, giving us the

impression of a constant flow.

The Sperling’s test

 George Sperling flashed a group

of letters for 1/20 of a second.

People could recall only about

half of the letters

 When he signaled to recall a

particular row immediately after

the letters disappeared with a

specific tone, they could do so with

near-perfect accuracy.

 Sperling proved all letters were

available in sensory memory if

they can be attended to quickly.

Rehearsal

 Repetition: Mental or verbal repetition of information allows information to remain in working memory longer than the usual 30 seconds.

 Meaningful association: Link the new information with existing

memories or knowledge already consolidated in long-term

memory.

Chunking

 A chunk is any memory pattern or meaningful unit of memory.

 By creating these chunks, a process called chunking, we can fit

more information into the seven available slots of working

memory.

 It expands working memory load

 Which is easier to remember?

4 8 3 7 9 2 5 1 6

483 792 516

Chess pieces chunking

 Chase and Simon (1973) used chess players.

 Novices – <100 hours

 Experts – >10,000 hours

Place pieces on the board (up to 24 of a middle game or random middle game) and players viewed for 5 seconds. Information in memory is stored as ‘chunks’

A chunk is a familiar pattern that can be used as a unit

Masters have about 100,000 chunks

Chunks can be recognized instantly

It takes about 10 seconds to create a chunk

Chess pieces chunking

 Information in memory is stored as

chunks (a familiar pattern that can be

used as a unit).

 Masters have about 100,000 chunks.

 They are linked to possible actions.

 In chess: identification of weaknesses,

moves, plans.

Chess pieces chunking

 The chess master is better at reproducing actual game positions.

 Master’s performance drops to level of beginner when pieces are arranged randomly.

Frontal cortex in short-term memory

 The monkey grabs a response lever

and fixates a small target. An

initial stimulus is briefly presented

and must be held in working

memory until the next stimulus

appears.

 In the task illustrated here, the

monkey was required to remember

the sample (“what”) and its location

(“where”) and release the lever

only in response to stimuli that

“matched” on both dimensions.

Neural firing rates in the lateral prefrontal cortex during

the delay period in the task are often above baseline.

Long-term memory

 Relatively permanent memory storage. As far as anyone knows,

there is no limit to the duration or capacity of the long-term memory.

 It is essentially all of your knowledge of yourself and the world

around you. Unless an injury or illness occurs, this memory is limitless.

Information processing

 Automatic processing

 Unconscious encoding of information.

 Examples:

 What did you eat for lunch today?

 Was the last time you studied during the day or night?

 You know the meanings of these very words you are reading. Are you

actively trying to process the definition of the words?

 Effortful processing

 Requires attention and conscious effort.

 Examples:

 Memorizing your notes for your upcoming Introduction to Psychology exams

 Repeating a phone number in your head until

you can write it down

Explicit vs Implicit learning

 Explicit Memory

 The types of memory elicited through the conscious retrieval of recollections in response to direct questions.

 Implicit Memory

 A nonconscious recollection of a prior experience that is revealed indirectly, by its effects on performance.

Explicit vs Implicit learning

 People with amnesia who read a story once, will read it faster a

second time, showing implicit memory.

 There is no explicit memory though as they cannot recall having seen the text

before

 People with Alzheimer's who are repeatedly shown the word

perfume will not recall having seen it.

 If asked the first word that comes to mind in response to the letters per, the say perfume readily displaying learning.

Type of long-term memories

Type of long-term memories

Remembering

 Refers to the subsequent re-accessing of events or information from the past,

which have been previously encoded and stored in the brain.

 There are two main methods of accessing memory: recognition and recall.

 Recognition is the association of an event or

physical object with one previously experienced,

and involves a process of comparison of

information with memory ( e.g. recognizing a known

face). It is a largely unconscious process.

 Recall involves remembering a fact, event or object

that is not currently physically present (in the sense

of retrieving a representation, mental image or

concept), and requires the direct uncovering of

information from memory, (e.g. remembering the

name of a recognized person).

Hermann Ebbinghaus (1850 –1909)

Barmen, Prussia (Germany)

 He founded the third psychological testing lab

in Germany (third to Wilhelm Wundt and

Georg Elias Müller).

 He began his memory studies here in 1879.

 In 1885, he published his groundbreaking Über

das Gedächtnis ("On Memory", later translated

to English as Memory. A Contribution to

Experimental Psychology) in which he described

experiments he conducted on himself to

describe the processes of learning and

forgetting.

Forgetting

 Forgetting curve for nonsense syllables

wyx

ghe

jek

lsm

 Forgetting occurs most

rapidly immediately after

learning.

 Relearning takes less time

than initial learning.

Forgetting

Forgetting can

occurs at any

stage.

Retrieval from long-term memory Depending on interference, retrieval

cues, moods, and motives, some

things get retrieved, some don’t

Long-term storage Some items are altered or lost

Short-term memory A few items are both noticed

and encoded

Sensory memory The senses momentarily register

amazing detail

Interference

 Retroactive Interference is the tendency for new information to disrupt the

memory of previously learned material.

 Proactive Interference is the tendency for previously learned material to

disrupt the recall of new information.

Decay

 Memories fade away or

decay gradually if

unused.

 Time plays critical role.

 Ability to retrieve

information declines with

time after the original

encoding.

Others reasons for forgetting

 Motivated forgetting:

 Involves the loss of painful memories (protective memory loss).

 Retrieval failure:

 The information is still within the long-term memory, but cannot

be recalled because the retrieval cue is absent.

Amnesia

 Amnesia is a form of memory impairment that affects all of the

senses.

 Typically, amnesiacs display deficits in specific types of memory

or in aspects of memory processing.

 Each type of functional deficit is associated with a lesion in a

different brain region.

Amnesia

 Retrograde amnesia is a form of amnesia where someone will be

unable to recall events that occurred before the development of

amnesia.

 Anterograde amnesia is a loss of the ability to create memories

after the event that caused the amnesia occurs

Concussion

The famous case of H.M.

 He suffered from progressively worsening

epilepsy. Over the years, his physicians

had tried to control his seizures with the

available drugs, but they were largely

ineffective. It became so bad that he was

having 10 minor seizures a day and a

major seizure every few days

 In 1953 at age 27, he had a bilateral

medial temporal lobectomy in an attempt

to cure his epilepsy.

 Although the surgery was partially

successful in controlling his epilepsy, a

severe side effect was that he became

unable to form new memories

(anterograde amnesia).

Henry Gustav Molaison

1926 – 2008

Connecticut, USA

The surgery

Image prior to surgery

(left). MRI image following

removal of right amygdala,

hippocampus, andanterior

temporal lobe (right).

The effects

 He allowed himself to be tested by

over 100 researchers.

 He had no other cognitive deficits.

His problem was purely a memory

problem.

 He could learn some things: tasks

that involved motor skills, perceptual

skills, or procedures became easier

over time, though he could not

remember practicing the new skill or

being asked to learn it.

Digit span

 A sequence of five digits

was asked to be repeated.

If correct, one more digit

was added. If not, that

sequence was repeated until

the participant reported it

correctly.

 Patients with amnesia may

have normal short-term

memory.

Evolved in time

 His memory for well before the surgey is intact, but that in the 50s (during his severe

epilepsy and surgery) declines and then in the 60’s and 70s (in the anterograde

domain) his recognition is nonexistent.

% C

o rr

e c t

Famous Faces Recognition by Decade

H.M.

Comparison

Electroconvulsive therapy

 Patients show a temporally grade retrograde memory loss. This tells us that

memory apparently changes for a long time after initial learning.

 Some material is forgotten, and the material that remains becomes more

resistant to disruption.

Alzheimer’s disease

 It is the most common form of dementia.

 Clinical description of the disease that bears his

name in 1906.

 It is a slowly progressive disease of the brain

that is characterized by impairment of memory

and eventually by disturbances in reasoning,

planning, language, and perception.

 The pooled incidence rate of AD among people

65+ years of age in Europe was 19.4 per 1000

person-years.

 The pooled data of population-based studies in

Europe suggests that the age-standardized

prevalence in people 65+ years old is 6.4 % for

dementia and 4.4 % for AD.

Aloysius Alzheimer

1864 -1915

Breslau, Germany

Hippocampus

 Research has found that one of

the first areas in the brain

affected by Alzheimer’s

disease is the hippocampus.

 Atrophy was correlated to the

hippocampal areas with the

presence of Alzheimer's disease.

Effects on the brain

Effects on memory

 This dysfunctional connectivity between the hippocampus and prefrontal cortex

due to the loss of acetylcholine appears to play a role in the progressive loss of

ability to form new episodic memories in Alzheimer’s patients.

Memory brain anatomy

Various type of memories

 For verbal working memory

tasks, they found activation

(increasing blood flow

coupled to increased neural

activity) in left -hemisphere

sites in inferolateral frontal

cortex.

 For the spatial working

memory task, activation was

primarily in right-hemisphere

regions.

Memory brain anatomy

 Amygdala: Emotional memory and memory consolidation.

 Basal ganglia & cerebellum: Memory for skills, habits and rhythm.

 Thalamus: Formation of new memories and working memories

 Cortical areas: Encoding of factual memories, storage of episodic and semantic

memories, skill learning, priming.

 Hippocampus: Memory recognition, spatial, episodic memory, laying down new

declarative long-term memories.

Electrical stimulation of circuits within

the hippocampus can lead to long-

term synaptic changes that seem to be

responsible for learning

The hippocampus

Importance of glutamate

 It is by a wide margin the most abundant neurotransmitter in

the vertebrate nervous system.

 It is used by every major excitatory function in the vertebrate

brain, accounting in total for well over 90% of the synaptic

connections in the human brain.

 It also serves as the primary neurotransmitter for some

localized brain regions, such as cerebellum granule cells.

Memory receptors

Excitatory post-synaptic potential

Excitatory post-synaptic potential

Long-term potentialisation (LTP)

 A stimulating electrode is placed in

the prefrontal path and a recording

electrode is placed in the dentrate

gyrus.

 LTP can be induced by stimulating

the axons with a burst of electrical

pulses (i.e., 100) within a few seconds.

 LTP is a persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse.

 Synapses that have undergone LTP tend to have stronger electrical responses to stimuli than other synapses.

Long-term potentialisation (LTP)

Synaptic Plasticity

 The size of the first population EPSP tells us

the strength of the synaptic connections before

LTP is induced.

 Evidence that LTP has occurred is obtained by

periodically delivering a single pulse and then

measuring the response in the DG to see if it is

bigger than the original response.

Chemistry of LTP

 Activation of terminal button

releases glutamate, which binds with

NMDA receptors in the postsynaptic

membrane of the dendritic spine

 If the membrane was depolarized

by a dendritic spike, then calcium ions

enter and activate CAM-KII

 CAM-KII travels to the postsynaptic

density and causes the insertion of

AMPA receptors

 LTP also initiates changes in synaptic

structure and production of new

synapses

Genetics of memory

 At the nucleus level, important nuclear

transcription factor recruit the

transcriptional machinery and initiate the

transcription of immediate early genes.

 Short-and long-term memory will lead to

the expression of numerous genes and

proteins.

Biological bases of memory

 Of all our forms of memory, a few

are exceptionally clear and vivid.

We call these flashbulb memories.

 These tend to be memories of

highly emotional events. Typically

people remember exactly where

they were when the event

happened, what they were doing

and the emotions they felt.

 Hormones and limbic driven releases

also affect memory.

That’s it for today!

It is so much better to rememeber.

Next class

Emotions