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Daniel Himmelstein
Physarum polycephalum
BBC Journal Club
link to source
link to source
plasmodium
• vegetative state
• acellular
• multinuclear
• protoplasmic veins
(tubules)
link to source
Ball et al. J Exp Bot. 2011
1,000-1,300Mya
700-1,000 Mya
Chernikova et al. Biology Direct. 2011
Nakagaki et al. Nature 2000
finds shortest path
hour 4 hour 8time 0
Maze Solving
coats entire agar plasmodium retracts
Tokyo Railway
Tero et al. Science 2010
Tero et al. Science 2010
Tero et al. Science 2010
• efficiency
• fault tolerance
• cost
Actual Rail Network Slime Tubule Network
Navigation Schemes
reactive
• immediate environment
• efficient
• novel exploration
global
• span entire search space
• map...
Slime mold uses an externalized
spatial “memory” to navigate in
complex environments.
Chris R. Reid,Tanya Lattya,Audrey Du...
Extracellular Slime Avoidance?
391
40
< 0.001
Slime Coated Agar Blank
1822
40
0.636
716
23
0.93
24 trials
120 hours
Does extracellular slime
function as a navigational aid?
blank
(trail perceivable)
slime coated
(trail...
blankagar
39 hours
71 hours
slimecoatedagar
Mean Speed of Plasmodium
50
0.345
2.5
millimeters per hour
Proportion Finding Goal
96%
33%
< 0.001
Mean Time to Reach Goal
800
0.012
40
hours
excluding trials over 120 hours
Mean Distance Traveled
5000
< 0.001
250
millimeters
Mean Time Spent in Trap
500
0.016
25
hours
Mean Time Spent on own slime trail
400
0.042
20
hours
13 trials 16 trials
measurement p-value
time to reach goal 0.374
distance travelled 0.471
speed 0.889
blankagar
39 hours
71 hours
slimecoatedagar
first conclusion: extracellular slime
avoidance provides a navigational benefit
• choice of 120 hour cutoff
• avoids extrace...
• “storage and retrieval of information
relating to past events”
• Spatial
• Externalized
• Collective
• Functional precur...
Memory
• epigenetic processes (chromatin structure)
• vernalization (chromatin remodeling
records length of winter)
• immu...
Memory
• epigenetic processes (chromatin structure)
• vernalization (chromatin remodeling
records length of winter)
• immu...
Memory
• epigenetic processes (chromatin structure)
• vernalization (chromatin remodeling
records length of winter)
• immu...
The End: Questions
Intelligent slime mold, but can it remember?
Intelligent slime mold, but can it remember?
Intelligent slime mold, but can it remember?
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Intelligent slime mold, but can it remember?

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A presentation on *Physarum polycephalum*, a slime mold, and its memory. I gave this talk on November 13, 2012 for the BBC Journal Club at UCSF.

The primary topic is the paper:
> Slime mold uses an externalized spatial “memory” to navigate in complex environments.
> https://dx.doi.org/10.1073/pnas.1215037109

Published in: Science
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Intelligent slime mold, but can it remember?

  1. 1. Daniel Himmelstein Physarum polycephalum BBC Journal Club link to source
  2. 2. link to source
  3. 3. plasmodium • vegetative state • acellular • multinuclear • protoplasmic veins (tubules)
  4. 4. link to source
  5. 5. Ball et al. J Exp Bot. 2011 1,000-1,300Mya 700-1,000 Mya Chernikova et al. Biology Direct. 2011
  6. 6. Nakagaki et al. Nature 2000 finds shortest path hour 4 hour 8time 0 Maze Solving coats entire agar plasmodium retracts
  7. 7. Tokyo Railway Tero et al. Science 2010
  8. 8. Tero et al. Science 2010
  9. 9. Tero et al. Science 2010 • efficiency • fault tolerance • cost Actual Rail Network Slime Tubule Network
  10. 10. Navigation Schemes reactive • immediate environment • efficient • novel exploration global • span entire search space • map precedes solution • no internalized memory
  11. 11. Slime mold uses an externalized spatial “memory” to navigate in complex environments. Chris R. Reid,Tanya Lattya,Audrey Dussutour, and Madeleine Beekman PNAS October 23, 2012 vol. 109 no. 43 17490-17494
  12. 12. Extracellular Slime Avoidance?
  13. 13. 391 40 < 0.001 Slime Coated Agar Blank
  14. 14. 1822 40 0.636
  15. 15. 716 23 0.93
  16. 16. 24 trials 120 hours Does extracellular slime function as a navigational aid? blank (trail perceivable) slime coated (trail masked) glucose plasmodium investigate the ability of the plasmodium to navigate around the trap and reach the glucose
  17. 17. blankagar 39 hours 71 hours slimecoatedagar
  18. 18. Mean Speed of Plasmodium 50 0.345 2.5 millimeters per hour
  19. 19. Proportion Finding Goal 96% 33% < 0.001
  20. 20. Mean Time to Reach Goal 800 0.012 40 hours excluding trials over 120 hours
  21. 21. Mean Distance Traveled 5000 < 0.001 250 millimeters
  22. 22. Mean Time Spent in Trap 500 0.016 25 hours
  23. 23. Mean Time Spent on own slime trail 400 0.042 20 hours
  24. 24. 13 trials 16 trials measurement p-value time to reach goal 0.374 distance travelled 0.471 speed 0.889
  25. 25. blankagar 39 hours 71 hours slimecoatedagar
  26. 26. first conclusion: extracellular slime avoidance provides a navigational benefit • choice of 120 hour cutoff • avoids extracellular slime for non- navigational reasons • do navigational benefits hold across a variety of complex environments • how are competing stimuli balanced
  27. 27. • “storage and retrieval of information relating to past events” • Spatial • Externalized • Collective • Functional precursor second conclusion: extracellular slime avoidance is a form of memory
  28. 28. Memory • epigenetic processes (chromatin structure) • vernalization (chromatin remodeling records length of winter) • immune response (antibodies) • evolution (stored adaptations) • ants (pheromone trails) • sticky notes “storage and retrieval of information relating to past events”
  29. 29. Memory • epigenetic processes (chromatin structure) • vernalization (chromatin remodeling records length of winter) • immune response (antibodies) • evolution (stored adaptations) • ants (pheromone trails) • sticky notes “internal storage and retrieval of information relating to past events”
  30. 30. Memory • epigenetic processes (chromatin structure) • vernalization (chromatin remodeling records length of winter) • immune response (antibodies) • evolution (stored adaptations) • ants (pheromone trails) • sticky notes “storage and retrieval of information relating to personal past events”
  31. 31. The End: Questions

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