Week 7 - Aidan

This weeks research was largely spent reading on magnetogenetics, consolidating what I've learned this summer from the Kaplitt Lab, and preparing for the presentation. Magnetogenetic treatments are typically a virally delivered protein that enables the stimulation or inhibition of nerves via external magnetic fields. A primary application of magnetogenetics is for pain treatment. Determining the efficacy of magnetogenetic treatments for chronic pain (CP) and spinal chord injury (SCI) models can currently only be studied indirectly in vivo. The Kaplitt Lab uses ferritin-TRPV1 transmembrane constructs that are hypothesized to open in response to external magnetic fields, enabling either an excitatory or inhibitory ion flow depending on the construct. The exact mechanism by which the channels open in response to the magnetic field are not known (though a few are hypothesized), which complicates the behavioral testing protocols, as certain magnetic devices may not stimulate via each mechanism equally. To test the efficacy for SCI models, we use place-preference and Von Frey (sensitivity) tests on mice. Prior attempts at place-preference testing using an acrylic behavioral chamber with an array of magnets demonstrated a preference for the non-magnetic side of the chamber by heatmap in all experimental groups. Our hypothesis, since there is no mechanism we are aware of for the magnetic field to negatively affect the mice, is that the sensation of the exposed magnets was unpleasant, and the field may have been too weak and non-uniform. The Halbach array device I have built will be used to repeat this testing, with a stronger and more uniform field. Additionally, we will cover the entire behavioral chamber in parafilm, so that a preference for flooring material does not impact the place-preference testing. We expect to see a preference for the magnetic half of the chamber in mice with SCI and ferritin-TRPV1, but no spatial preference in any of the other experimental groups.