memory cellular and molecular basis of memory engram temporal types of memory

Memory

Cellular and Molecular Basis of Memory Engram

Temporal Types of Memory

Memory

ability

to accept information (encoding)

to store (storage)

to retrieve (retrieval)

information from NS

Memory involves at least four distinct processes:

Encoding - incoming information must be perceived

Consolidation – newly stored information is labile, to make it more stable (expression of genes, structural changes

Storage- to retain over time, almost unlimited capacity

Retrieval – to bring different kinds of information together, it is constructive process, subject to distortion

Consolidation

Retrograde amnesia

A person who has been knocked unconscious selectively loses memory for events that occured before the blow

Retrieval

recall (reproduction) - serial

- free recall

- cued record (with help, hint) (reproduction of paired associations)

Recognition (to recognize again)

•Memory vs learning

Engram (print, foot-mark)

•Memory is not homogeneous •Duration, persistence•Brain structures•Molecular mechanisms

Donald Olding Hebb

*1904 †1985

Canadian psychologist

Hebbian theory:

When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased

Hebb's Law.

"Neurons that fire together wire together."

Eric Richard Kandel

•1929 Vienna

2000 Nobel Prize in Physiology or Medicine

The California sea slug (Aplysia californica) is also commonly called the California sea hare, and this is because the shape of all Aplysia species is reminiscent of the shape of a rabbit or hare. Sea hares are a kind of shell-less sea snail, a marine mollusk

Experimental support for Hebbian learning

http://en.wikipedia.org/wiki/Image:Eric_Richard_Kandel.jpg

http://en.wikipedia.org/wiki/Image:Eric_Richard_Kandel.jpg

Molecular mechanisms

• Posttetanic potentiation (short term potentiation)

Long term potentiation LTP

Posttetanic potentiation


Large Ca2+ influx. Saturation of the various Ca2+ buffering systems (ER, mitochondia)

Temporary excess of Ca2+ is called residual Ca2+.

Concentration of free Ca2+

increases the amount of transmitter released


A hight rate of stimulation of the presynaptic neuron

A gradual increase in the amplitude of the postsynaptic potential

Postsynaptic potential increases in size = potentiation


The enhancement in the strength of the synapse represents storage of information about previous activity

It can lasts minutes but can persist for an hour.

An elementary form of memory

NMDA – glutamate receptor

Glutamate

receptors


Glutamate synapse

Both NMDA and AMPA receptors

Increase the sensitivity Increase the number of postsynaptic AMPA receptors


retrograde messenger (NO)


retrograde messenger (nitric oxide)

Postsynaptic part

Presynaptic part

NO initiate an enhancement of transmitter release that contributes to LTP

NMDA redeptor

New synapses

Ca2+ + calmodulin

Transcription - mRNA

Translation - proteins


New synapses


retrograde messenger NO (enhancement of transmitter release )

Increase in the sensitivity and number of postsynaptic AMPA receptors

Temporal phases of memory

(based on different biological mechanisms)

Iconic (visual) – reflect the activity of sensory buffers, continuation of sensory neural activity

Short-term memories – last for seconds up to a minutes

Long-term memory – weeks, months, years, for the rest of the life of an organism (permanent memory)

Working memory (short-term plus activated long term memory)

A scheme of memory processes that includes encoding, consolidation and retrieval

Iconic (visual) echoic (auditory) – reflects the activity of sensory buffers, continuation of sensory neural activity

Iconic memory (visual persistence, example burning ring)

George Sperling 1960

In Sternberg R.J.: Kognitivní psychologie, Portál, Praha 2002: s. 187.

Experiment: whole-report procedurePresentation 50 msRecall of 3-5 symbols

Iconic (visual)

George Sperling 1960

Experiment: partial-report procedure

Presentation 50 msCued recall – The frequency of

the tone (high, medium, or low) indicated which set of

characters within the display were to be reported Recall of 9 symbols Sperling's original partial report paradigm

Iconic memory is described as a very brief (<1000 ms), pre-categorical, high capacity memory store

Short-term memories

last for seconds up to a minutes

capacity 7 ± 2 items

Verbal memory

AVLT Auditory Verbal Learning Test

Remember folowing words

Verbal memory

AVLT

Who recall word

table

light

bench

pillow

Dick

1. table2. cloud3. bookcase4. tree5. shirt6. cat7. light8. dick9. bench10. chalk11. flower12. bat13. blanket14. soap15. pillow

Verbal memory

Ebinghaus curve

order in series

What is first

What is fresh (last word)

Verbal memory

Better memory for

What concern you personally

Personally interesting

Unusual

Connected with emotions

erotic subtext

Comparison of verbal and visual memory

Explore each picture

Write down names of things

Envelope

Music

Bird

Brush

Palette

Tin

Screwdriver

Telephone

Fireman

Stairs

Dustbin

Bike

Money

Hen

Lettuce

Interactive image

Pacient H.M.

Long term memory

H.M. was taught to trace between two outlines of a star while viewing his hand in a mirror

Regions of the human brain that have been implicated in the formulation of long-term declarative memories.

A lateral view of the brain shows the levels of the transverse sections

Cross sections in two levels

DeclarativeExplicit

Nondeclarative Implicit

EpisodicStore events autobiographical

Semantic

Nonassociative

Associative learning

Long term memory classification

Epizodic-like memory test

DeclarativeExplicit


EpizodicStore events autobiografic

SemanticStore facts

Nonassociative



Morris water maze

Temporal lobe lesion

Blue velvet arena

Test: Hidden goal in Blue velvet arena

Alzheimer disease

Control group

Vascular dementia

Mild cognitive impairment

Epizodic-like memory test

DeclarativeExplicit



SemanticStore facts

Non-associativeNo relation between two or more stimuli, behavior and its consequence are not related to.



Habituation

Sensitization

Imprinting

Long term memorynonassociateve

HabituationAn animal responds less and less strongly to uniform gentle taps on its surface.

Decreas in response to repeated stimulus

Long term memorynonassociateve

SensitizationBy a strong stimulation.A single electrical shock to the skin. Stronger reaction to the weak tap.

Increas in response to repeated stimulus

Long term memory

nonassociateve

Imprinting

Konrad Lorenz

Greylag geese

incubator-hatched geese would imprint on the first suitable moving stimulus

the goslings would imprint on Lorenz himself

Konrad Lorenz

imprinted goslings

Critical period

http://images.google.com/hosted/life/f?q=lorenz+imprinting&prev=/images%3Fq%3Dlorenz%2Bimprinting%26gbv%3D2%26hl%3Dcs%26sa%3DG&imgurl=ac71586ffcee0400

DeclarativeExplicit



SemanticStore facts

Nonassociative

associative learning – relation between stimulus-response two or more stimuli, events,behavior – its consequence

Long term memory

classical conditioning instrumental, operant conditioning (standard or motor learning) conditioned taste aversion priming

Ivan Petrovič Pavlov

Classical conditioning

Sir Charles Scott Sherrington

Classical conditioning

Standard operant conditioning

Edward Lee Thorndike

(1874 - 1949)

Standard operant conditioning

Skinner`s box

Priming

Priming

ABSENT

INCOME

FILLY

DISCUSS

CHEESE

ELEMENT

Priming

Priming

ABS

INC

FIL

DIS

CHE

ELE

Summary

Molecular level, synapses

Posttetanic potentiation Long term potentiation

DeclarativeExplicit


EpisodicStore events autobiographical

Semantic

Nonassociative


Iconic memoryShort term memory


memory cellular and molecular basis of memory engram temporal types of memory

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