Neurophysiology and Brainstimulation

Description

Transcranial magnetic stimulation (TMS) is a widely used non-invasive method for the investigation and modulation of human brain functions. However, the activity of individual neurons evoked by TMS has remained largely inaccessible due to the large TMS-induced electromagnetic fields.

In collaboration with our cooperation partners, we have developed a general method that provides direct electrophysiological in vivo access to TMS-evoked neuronal activity 0.8-1 ms after the TMS onset. This time-window was previously not visible due to the superposition by the magnetic fields.  

In order to gain a deeper understanding of the physiological processes in humans, we translate the stimulation protocols used in humans to rodents. For single-pulse TMS, we could show that evoked activity of neurons in the motor cortex within the first 6 ms shows high frequency peaks depending on TMS-induced current orientation. A multiphase spike rhythm alternating between excitation and inhibition occurs in the time window of 6-300 ms after the TMS pulse. This pattern can be associated with various human TMS responses recorded at the spinal cord and muscle level.

Our approach opens a new level of insight into TMS-brain interactions, which is crucial for the development of new non-invasive tools for targeted research and effective treatment of the human brain.

 

  

Current Projects

Brain-stimulation and cortical plasticity

Brain-stimulation and cortical plasticity

In the past, methods such as brain stimulation were used to understand the brain and its functions. Later it was found that brain stimulation can also lead to changes in the brain functions and trigger plasticity, a potential of the brain to react to new environmental conditions.
  

Publications

Pfeiffer, F. & Benali, A. (2020). Could non-invasive brain-stimulation prevent neuronal degeneration upon ion channel re-distribution and ion accumulation after demyelination?. Neural Regeneration Research, 15(11), 1977-1980. [More] 
Li, B., Virtanen, J. P., Oeltermann, A., Schwarz, C., Giese, M. A., Ziemann, U. et al. (2017). Lifting the Veil on the Dynamics of Neuronal Activities Evoked by Transcranial Magnetic Stimulation. eLife pii: e30552. [More] 
Benali, A., Trippe, J., Weiler, E., Mix, A., Petrasch-Parwez, E., Girzalsky, W. et al. (2011). Theta-burst transcranial magnetic stimulation alters cortical inhibition. J Neurosci, 31(1193-1203). [More] 
Benali, A., Weiler, E., Benali, Y., Dinse, H. & Eysel, U. (2008). Excitation and inhibition jointly regulate cortical reorganization in adult rats. J Neurosci, 28, 12284-12293. [More]