Cooled Rat Coil

For Unilateral Single Pulse and Repetitive Transcranial Magnetic Stimulation of Small Animals

  • Optimal coil size allowing for focused unilateral stimulation
  • Magnetic field strong enough to produce reliable unilateral response and record MEP
  • Dynamic liquid cooling allowing for high-frequency rTMS protocols
  • Unilateral single pulse and repetitive transcranial stimulation of small animals
Cooled Rat Coil


Optimal Coil Size Allowing for Focused Unilateral Stimulation

Scientists from different brain research areas traditionally use animal models in experiments. One of the widely used models is the rodent brain. Therefore researchers today need modern tools for transcranial magnetic stimulation of rodents. One of the most technically challenging tasks is to perform unilateral TMS of rats. Modeling of electrical field distribution generated by figure-of-eight TMS coil using the fine element model of rat brain shows that optimal size of one coil winding should be about 25 mm. A rat coil was subsequently developed based on this specification and successfully validated.

Magnetic Field Strong Enough to Produce a Reliable Unilateral Response and Record MEP

First prototype of the coil was tested in Neurosoft TMS lab and then by the Biomedical MR Imaging & Spectroscopy Group of the UMC Utrecht Center for Image Sciences. Experiments clearly showed that the cooled rat coil can reliably evoke unilateral motor evoked potentials in rats.

Dynamic Liquid Cooling Allowing for High-Frequency rTMS Protocols

For its small size, the coil has a very limited possibility to dissipate the heat appearing in the windings when a high electrical current passes the coil during stimulation. To avoid the heating and make the coil able to perform long stimulation sessions, an active liquid cooling system was added to the coil.

Unilateral Single Pulse and Repetitive Transcranial Stimulation of Small Animals

Focused repetitive transcranial magnetic stimulation is widely used for brain activity modulation. This modulation is already actively applied for the treatment of an extensive list of psychiatric and neurological diseases in humans including stroke, Parkinson's disease, depression, etc. However, the mechanism of this action is still being investigated. Allowing for focused and navigated repetitive stimulation of the animal models of the diseases, the small coil could help understand such mechanism. The next task for the developer team was to make the coil able to perform long treatment sessions. To solve this task the internal geometry of the cavies where the liquid is circulated was optimized and several temperature sensors were added to the coil. The coil can now perform long HF and LF rTMS sessions.

Cooled Rat Coil exclusively distributed worldwide by Soterix.