TMS – EEG

 

The integrated system combining Transcranial Magnetic Stimulation (TMS) and electroencephalography (EEG) is a novel multi-modal approach which offers new prospects in cognitive neuroscience. TMS-EEG allows to measure cortical excitability and effective connectivity with a good spatial and temporal resolution.

 

 

Combining TMS with electroencephalography enhances the properties of the two techniques.

 

 

TMS-EEG allows indeed a direct measurement of the excitability of any cortical area (beyond primary motor or visual area) by directly perturbing the cortical activity, by means of TMS, and recording  with the EEG the cortical response to this perturbation with a high temporal resolution (Taylor et al., 2008), computed as TMS-Evoked Potentials (TEPs).  Continuous high definition EEG recording permits to probe the state of broader cortical networks, unveiling how activation spreads from the stimulated area to interconnected ones, thus allowing a direct measure of effective connectivity. TEPs are considered a reliable measure of brain activation state (Miniussi and Thut, 2010); beside, as long as the same parameters across sessions are maintained, the reliability of the technique has been probed (Casarotto et al., 2011), allowing to link any observed changes in TEPs to the experimental condition (i.e. brain state, task execution, neuromodulation, etc) rather than to others confounding variables.

The Neurostimulab has used TMS-EEG to trace online and off-line changes in cortical excitability induced by tDCS both at resting state and during task execution in healthy population. Since TEPs analysis provides clear cut information on the speed and the location of cortico-cortico interactions, we are employing this technique also to clarify the temporal dynamics of neural transmission and how different regions of brain networks communicate during the cognitive processing required by different types of tasks, such as face expression detection, prismatic adaptation and a visuo-tactile multisensory processing.

 

 

RELATED RESEARCH

 

TDCS increases cortical excitability: Direct evidence from TMS–EEG.

Lauro, L. J. R., Rosanova, M., Mattavelli, G., Convento, S., Pisoni, A., Opitz, A., … & Vallar, G.  Cortex (2014).

 

Top-down interference and cortical responsiveness in face processing: a TMS-EEG study.

Mattavelli, G., Rosanova, M., Casali, A. G., Papagno, C., & Lauro, L. J. R.  NeuroImage (2013). 76, 24-32.

 

Localizing the effects of anodal tDCS at the level of cortical sources: A Reply to Bailey et al., 2015.

Lauro, L. J. R., Pisoni, A., Rosanova, M., Casarotto, S., Mattavelli, G., Bolognini, N., & Vallar, G.  Cortex (2016).

 

Timing of emotion representation in right and left occipital region: Evidence from combined TMS-EEG.

Mattavelli, G., Rosanova, M., Casali, A. G., Papagno, C., & Lauro, L. J. R.  Brain and cognition (2016).

 

Cognitive Enhancement Induced by Anodal tDCS Drives Circuit-Specific Cortical Plasticity.

Pisoni, A., Mattavelli, G., Papagno, C., Rosanova, M., Casali, A. G., & Romero, L. L. Cerebral cortex(2017).