Deciphering learning and memory mechanism
15, May. 2009 Inaugural Symposium
Memory and Cognition
Cognition “The psychological result of perception and learning and reasoning”“Mental functions such as the ability to think, reason, and remember”
G
BCS
Graham& Kei
Eating seafood with Min
Fado
Cues
Ret
riev
al
Reconsolidation
Incoming information
Sensoryorgans Attended to
Short-termstorage Consolidation
Long-termstorage
Rehearsed
Multistage memory model(Modified from Bower, 1967)
Outside world
Our Main Questions
2) How is memory reorganized during reconsolidation process ?
1) What molecular mechanism underlies memory consolidation process ?
3) How can we erase our bad memory?
ReconsolidationReconsolidation
ConsolidationConsolidation
ExtinctionExtinctionExtinction
Model Organisms
Aplysia Mouse1) Largest neurons in the animal kingdom
2) Simple nervous system: 20,000 neurons
3) In vitro synapse culture
1) Transgenic animals
2) Various forms of associative memory
Consolidation
Short-termmemory
Long-termmemoryConsolidationConsolidation
- Transcription & translation-independent- Modification of existing moleculesSTM
- Transcription & translation-dependent - Structural changes : synaptic growthLTM
Consolidation of LTF in Aplysia
• Transcription factors involved in consolidation • 5-HT receptor
(Lee et al., M
ol B
rain, 2
008)
Reconsolidation
Consolidated state
Labile state
?Proteinsynthesis
Reactivated memory becomes labile and modifiable, and has to undergo some new process of stabilization depending on de novo protein synthesis. ( Misanin et al, 1968; Nader et al., 2000; Dudai, 2004 )
Protein degradation
MEMORY
Protein degradation and resynthesis in the synapse induced by memory retrieval
Kaang, B.K.Kaang, B.K.
Collingridge, G.L.Collingridge, G.L.
Zhuo, M.Zhuo, M.
Lee, I.Lee, I. Kim, S.J.Kim, S.J.
Cho, K.Cho, K.
“Silencing” or “TB” project
T.V.P Bliss & Lømo (1973) J. Physiol.
Synaptic plasticity is both necessary and sufficient for the information storage in the brain.
Hypothesis of TB project
• Testing the hypothesis
1) Memory is formed through strengthening a unique set of synaptic connection.
2) One neuron might attend to several memory circuits. If specific synapses are inactivated, specific memory would be impaired.
Event AEvent A
Event BEvent B
Synaptic specificity
Thanks to:Lab members Deok-Jin JangHyoung KimSue-Hyun LeeChi-Hoon Lee Jae-Ick KimHyoung-Gon KoHye-Ryeon LeeHeejung JunJun-Hyeok ChoiNam-Kyung YuSun-Lim ChoiNuribalhae LeeJung-Eun KimChuljung KwakSuwon ParkYeon-Su Chae
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