Natures wonders: using the magnetic field (dhw note) (Introduction)

by David Turell @, Wednesday, July 01, 2015, 14:49 (1830 days ago) @ David Turell

C. elegans, the nematode worm uses the magnetic field to burrow vertically into the ground, oppositely as expected in the Northern and Southern hemispheres:

"It turns out, however, that the worms don't migrate exactly along the field lines. The earth's magnetic field can be understood mathematically as a vector that points in different directions at different positions on the surface of the earth. Since it is a vector, one can calculate the component of the field that aligns with the horizontal surface of the earth, or the component that is perpendicular to the earth's surface. C. elegans seems able to detect this vertical component of the field that is perpendicular to the earth's surface, because they orient themselves vertically while burrowing.


"Then, they performed an experiment using genetically fluorescent AFD neurons, which light up when activated. When the neurons were in the presence of a magnetic field, the researchers could visually detect activity. It's still not completely understood how exactly the process works, but this work allowed the investigators to identify some of the precise cell-types and ion channels responsible for magneto-sensitivity.

"So what is necessary for this behavior? According to the paper:

"The AFD sensory neuron pair is necessary for magnetic orientation and for vertical migrations. Similarly, a cGMP-gated ion channel in the AFD neurons, TAX-4, is also necessary and sufficient for these behaviors.
But it's not enough to have these cells and ion channels, which are able to sense the magnetic field. The worms also need the proper response behavior encoded in their neurons, enabling them to burrow downward when feeding. Because worms in different hemispheres respond differently to the field, the team proposed that this response behavior is genetically encoded."

Comment: When this research is finished it will show, I predict, an entire automatic system for behaviour that appears 'sentient'. But does the worm have a degree of mentation, or a degree of unrestricted or independent mentation? Note the worm repeats the same behaviour over and over consistently.

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