1. Brain-inspired Approaches for De Bruijns model of associative memory
Femke Jansen

2. Contents Overview of the model Brain-inspired approaches Conclusions
Lower & upper layer
A simple scenario
Brain-inspired approaches
Ideas
Issues & resolutions
Conclusions
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3. Overview of the model Lower layer: single cells
“Bowl” of soup: chemical compounds
Chemical reactions via signals
Storage: A + B → C
Retrieval: A + C → B
Associative memory
Soup “knows” about (p, q)
Only recalls when p?
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4. Overview of the model (2)
Upper layer: brain + set of cells
Distributes work over cells
Roaming random set
Cells connected to the brain: communication
Bidirectional communication
Connect & disconnect at random
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5. Overview of the model (3)
Limitations of individual cells
Decay period: not stored indefinitely
Capacity: store maximal X pairs
Unreliability: fail to reply to p?,
although it stores a pair containing p
Then how can this work?
Redundancy!
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6. A simple scenario for the upper layer
Small example
3 brain cells in roaming random set
Initially, no compounds present
For simplicity, no deterioration of compounds
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7. Brain-inspired Approaches - ideas
Slowing down dementia
Idea: stimulate patients with signals - help them remember
How it works:
stimulate brain of patients to broadcast signals
more often broadcasted  more cells contain the signals
mental activity  “fitter” brain
How it helps people:
remain longer self-reliant
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8. A BiA- ideas (2) Helping people with dyslexia
Idea: stimulate patients with signals as
(letter, looks like) or (letter, sounds like).
How it works:
similar to dementia: broadcasted often  more cells contain the signals
perhaps easier/faster then learning process
How it helps people:
dyslexia is treated better at an early age A
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9. BiA- ideas (3) Processing traumas
Idea: traumas can be “hidden”; stimulating patients with signals to let traumas arise
How it works:
use signals (i.e., memories) from the past
connected cells involved will reply with a part  trauma unfolds itself
How it helps people:
dealing with a trauma requires recalling it
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10. BiA- ideas (4) Example to illustrate trauma recall
For simplicity, only second half of pairs shown: pairs that contain a fragment of a trauma
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11. BiA- issues & resolutions
How to stimulate patients?
Invasive: implant, directly in contact with cells
Non-invasive: helmet, no direct contact
What kind of signals correspond to features (i.e., memories)?
Difficult:
varies from person to person
requires knowledge from many fields: biology, chemistry, physiology …
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12. BiA- issues & resolutions (2)
The next step: understanding relations between pairs
in vitro experiments - brain cells / small neural networks
provide input, observe output (electrical / light)
not as complex as the (human) brain
in vivo experiments - smaller animals (mice)
influence from cooperation of areas in the brain
age as a limiting factor (mice: lifespan of 2 years)
eventually, test on humans
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13. Questions? Conclusions Main ideas model:
cells store signals of pairs and can reply to a query  associative memory
distributing work over cells: different pairs stored
Brain-inspired approaches may exploit these features
Still: difficult, because of chemical & biological aspects
Once aspects fully understood, conduct experiments:
in vitro for initial idea
in vivo for interaction of different brain areas
Questions?
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