Axel Thielscher

Danish Research Centre for Magnetic Resonance, Hvidovre Hospital, Copenhagen

Title: "Calculating and measuring the current flow during transcranial brain stimulation"

Abstract:

Individualized electric field calculations based, e.g. on Finite-Element Methods, might be a valuable tool to improve spatial targeting of transcranial brain stimulation (TBS). I will give an overview of our ongoing work to improve, validate and apply field calculation methods in the context of TBS. This will cover the implementation and validation of better methods to generate head models from MRI scans, the use of field calculations to review some of the montages used in recent dual-site TACS (transcranial alternating current stimulation) studies, and the combination of field calculations with optimization methods to improve spatial targeting when using multichannel TDCS (transcranial direct current stimulation).

While the anatomical accuracy of the employed head models has improved in the last few years, the accuracy of the field simulations is still limited by the uncertainty of the ohmic tissue conductivities. The conductivity values are based on a rather sparse literature with a substantial spread across studies, highlighting the need for validation studies. In the last part of the talk, I will present our initial results of in-vivo measurements of the TACS current flow in the human brain based on Magnetic Resonance Current Density Imaging (MRCDI), and will briefly relate them to the results of recent invasive recordings of the TACS electric field in patients performed by another group. 

Read more at: http://www.drcmr.dk/Thielscher