Rat Behavioral Changes Due to Implanted Magnetic Particles Activated with Externally-Applied Magnetic Fields^*

摘要

While many techniques are available to manipulate deep brain structures (optogenetics, deep brain stimulation, ultrasound, transcranial magnetic stimulation) to treat psychiatric and neurologic disorders, there are issues that remain which decrease clinical utility. For example, DBS is invasive and only able to directly impact a small portion of the brain at a time. Recent data has shown that mechanical stimulation of neurons depolarizes the cells increasing their firing rate. Here we implanted magnetic nanorods into neural tissue of live rats. We then designed a magnetic coil to provide external magnetic stimulation to the implanted nanorods while rats were awake and ambulatory.Male rats were stereotactically implanted with magnetic nanorods. Control animals experienced sham surgeries. One week following surgery, animals were placed in a small open space within a coil. Low-magnitude (5 mT, 20 Hz) external magnetic stimulation was applied. Total locomotion, rotations, and chewing behaviors of the rats for the duration of the experiment (7 minutes) were measured. Animals with implanted nanorods showed significantly increased levels of chewing behavior compared to sham controls. These data demonstrate the ability of mechanical stimulation of striatal neurons to modify rat behavior. Potential future applications of the technology include the use of wearable generators of low magnetic fields applied to intra-nasally administered magnetic nanoparticles.