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
9. Tero et al. Science 2010
• efficiency
• fault tolerance
• cost
Actual Rail Network Slime Tubule Network
10. Navigation Schemes
reactive
• immediate environment
• efficient
• novel exploration
global
• span entire search space
• map precedes solution
• no internalized memory
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
17. 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
27. 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
28. • “storage and retrieval of information
relating to past events”
• Spatial
• Externalized
• Collective
• Functional precursor
second conclusion: extracellular
slime avoidance is a form of memory
29. 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”
30. 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”
31. 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”