Cellular and Molecular Basis of Memory Engram Temporal Types of Memory

to accept information (encoding) to retrieve (retrieval) 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

2000 Nobel Prize in Physiology or Medicine 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 memory (visual persistence, example burning ring) 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.

partial-report procedure 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 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 AVLT Who recall word table light bench pillow Dick

What is fresh (last word) 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

Interactive image 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   Nondeclarative Implicit Episodic Store events autobiographical Semantic Non associative Associative learning

Long term memory classification Declarative Explicit   Nondeclarative Implicit Episodic Store events autobiographical Semantic Non associative Associative learning

Epizodic-like memory test

Long term memory classification Declarative Explicit   Nondeclarative Implicit Epizodic Store events autobiografic Semantic Store facts Non associative Associative learning

Morris water maze

Temporal lobe lesion

Blue velvet arena

Test: Hidden goal in Blue velvet arena Alzheimer disease Vascular dementia Control group Mild cognitive impairment

Epizodic-like memory test

Long term memory classification Declarative Explicit   Nondeclarative Implicit Epizodic Store events autobiografic Semantic Store facts Non- associative No relation between two or more stimuli, behavior and its consequence are not related to. Associative learning Habituation Sensitization Imprinting

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

Long term memory Declarative Explicit Nondeclarative Implicit Epizodic   Nondeclarative Implicit Epizodic Store events autobiografic Semantic Store facts Non associative 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

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

Long term memory classification Iconic memory Short term memory Long term memory classification Declarative Explicit   Nondeclarative Implicit Episodic Store events autobiographical Semantic Non associative Associative learning