m8ta
use https for features.
text: sort by
tags: modified
type: chronology
{1459}
hide / / print
ref: -2018 tags: Michael Levin youtube talk NIPS 2018 regeneration bioelectricity organism patterning flatworm date: 04-09-2019 18:50 gmt revision:1 [0] [head]

What Bodies Think About: Bioelectric Computation Outside the Nervous System - NeurIPS 2018

  • Short notes from watching the video, mostly interesting factoids: (This is a somewhat more coordinated narrative in the video. Am resisting ending each of these statements with and exclamation point).
  • Human children up to 7-11 years old can regenerate their fingertips.
  • Human embryos, when split in half early, develop into two normal humans; mouse embryos, when squished together, make one normal mouse.
  • Butterflies retain memories from their caterpillar stage, despite their brains liquefying during metamorphosis.
  • Flatworms are immortal, and can both grow and contract, as the environment requires.
    • They can also regenerate a whole body from segments, and know to make one head, tail, gut etc.
  • Single cell organisms, e.g. Lacrymaria, can have complex (and fast!) foraging / hunting plans -- without a brain or anything like it.
  • Axolotl can regenerate many parts of their body (appendages etc), including parts of the nervous system.
  • Frog embryos can self-organize an experimenter jumbled body plan, despite the initial organization having never been experienced in evolution.
  • Salamanders, when their tail is grafted into a foot/leg position, remodel the transplant into a leg and foot.
  • Neurotransmitters are ancient; fungi, who diverged from other forms of life about 1.5 billion years ago, still use the same set of inter-cell transmitters e.g. serotonin, which is why modulatory substances from them have high affinity & a strong effect on humans.
  • Levin, collaborators and other developmental biologists have been using voltage indicators in embryos ... this is not just for neurons.
  • Can make different species head shapes in flatworms by exposing them to ion-channel modulating drugs. This despite the fact that the respective head shapes are from species that have been evolving separately for 150 million years.
  • Indeed, you can reprogram (with light gated ion channels, drugs, etc) to body shapes not seen in nature or not explored by evolution.
    • That said, this was experimental, not by design; Levin himself remarks that the biology that generates these body plans is not known.
  • Flatworms can sore memory in bioelectric networks.
  • Frogs don't normally regenerate their limbs. But, with a drug cocktail targeting bioelectric signaling, they can regenerate semi-functional legs, complete with nerves, muscle, bones, and cartilage. The legs are functional (enough).
  • Manipulations of bioelectric signaling can reverse very serious genetic problems, e.g. deletion of Notch, to the point that tadpoles regain some ability for memory creation & recall.

  • I wonder how so much information can go through a the apparently scalar channel of membrane voltage. It seems you'd get symbol interference, and that many more signals would be required to pattern organs.
  • That said, calcium is used a great many places in the cell for all sorts of signaling tasks, over many different timescales as well, and it doesn't seem to be plagued by interference.
    • First question from the audience was how cells differentiate organismal patterning signals and behavioral signals, e.g. muscle contraction.