Transcript 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
Hebb's Law.
"Neurons that fire together wire together."
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
Eric Richard Kandel
•1929 Vienna
2000 Nobel Prize in
Physiology or Medicine
Experimental support for Hebbian
learning
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
Molecular mechanisms
• Posttetanic potentiation (short term
potentiation)
Long term potentiation LTP
Posttetanic potentiation
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
Posttetanic potentiation
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
Posttetanic 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
Long term potentiation LTP
NMDA – glutamate
receptor
Glutamate
receptors
Long term potentiation LTP
Glutamate synapse
Both NMDA and AMPA
receptors
Long term potentiation LTP
Increase the sensitivity
Increase the number of
postsynaptic AMPA
receptors
retrograde messenger
(NO)
Long term potentiation LTP
Postsynaptic part
NMDA
redeptor
retrograde messenger
(nitric oxide)
Presynaptic part
NO initiate an enhancement of transmitter release
that contributes to LTP
Long term potentiation LTP
New synapses
Ca2+ + calmodulin
Transcription - mRNA
Translation - proteins
Long term potentiation LTP
Increase in the
sensitivity
and number of
postsynaptic AMPA
receptors
retrograde messenger
NO (enhancement of
transmitter release )
New synapses
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
Experiment:
whole-report procedure
Presentation 50 ms
Recall of 3-5 symbols
In Sternberg R.J.: Kognitivní psychologie,
Portál, Praha 2002: s. 187.
Iconic (visual)
George Sperling 1960
Experiment:
partial-report procedure
Presentation 50 ms
Cued 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. table
2. cloud
3. bookcase
4. tree
5. shirt
6. cat
7. light
8. dick
9. bench
10. chalk
11. flower
12. bat
13. blanket
14. soap
15. 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
Long term memory
Pacient H.M.
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
Long term memory classification
Declarative
Explicit
Episodic
Store events
autobiograph
ical
Semantic
Nondeclarative
Implicit
Non
associative
Associative
learning
Long term memory classification
Declarative
Explicit
Episodic
Store events
autobiograph
ical
Semantic
Nondeclarative
Implicit
Non
associative
Associative
learning
Epizodic-like memory test
Long term memory classification
Declarative
Explicit
Epizodic
Store events
autobiografic
Semantic
Store facts
Nondeclarative
Implicit
Non
associative
Associative
learning
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
Long term memory classification
Declarative
Explicit
Epizodic
Store events
autobiografic
Semantic
Store facts
Habituation
Sensitization
Imprinting
Nondeclarative
Implicit
Nonassociative
No relation
between two or
more stimuli,
behavior and
its consequence
are not related
to.
Associative
learning
Long term memory
nonassociateve
Habituation
An animal responds
less and less strongly
to uniform gentle taps
on its surface.
Decreas in response
to repeated stimulus
Long term memory
nonassociateve
Sensitization
By 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
Critical period
imprinted goslings
Declarative
Explicit
Nondeclarative
Implicit
Long term memory
Epizodic
Store events
autobiografic
Semantic
Store facts
associative
learning –
Non
relation between
associative
stimulus-response
two or more
stimuli, events,
behavior – its
consequence
classical conditioning
instrumental, operant conditioning
(standard or motor learning)
conditioned taste aversion
priming
Classical conditioning
Ivan Petrovič Pavlov
Classical conditioning
Sir Charles Scott Sherrington
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
Iconic memory
Short term memory
Long term memory classification
Declarative
Explicit
Episodic
Store events
autobiograph
ical
Semantic
Nondeclarative
Implicit
Non
associative
Associative
learning