Plasticity

Brain plasticity in healthy participants. In the CNRS laboratory, we conducted studies to characterize the reproducibility of TMS-induced plasticity in healthy volunteers (Vernet et al., 2014c). Besides, using TMS-EEG combination, we revealed the underlying mechanisms of TMS-induced plasticity in terms of modulation of cortical oscillations in specific frequency bands (Vernet et al., 2013).

Brain plasticity in patients. We demonstrated a decrease in cortical plasticity during aging, which is worsened by neurodegenerative diseases (Freitas et al., 2011; Pascual-Leone et al., 2011; Bashir et al., 2014). Similarly, we measured an abnormal plasticity in mild traumatic brain injuries two weeks after the concussion, which normalizes 4 weeks later (Vernet et al., 2012b, Bashir et al., 2012; Tremblay et al., 2015). This type of measure could participate in decisions on when the patient could resume normal activities and guide intervention protocols. Better characterize plasticity induction mechanisms will also contribute to optimize treatment with non-invasive stimulation techniques, e.g., following a stroke affecting motor skills (Bashir et al., 2016), or while undergoing neurodegenerative disorders impacting language (Teichmann et al., 2016).

Brain connectivity in patients. Thanks to the TMS-EEG combination, we can revisit classic neurology syndromes. In a patient with a disconnection syndrome we could observe a lack of activity spreading from one hemisphere to another (Pereira et al., 2012). Finally, we demonstrated, in patients with brain developmental malformations leading to heterotopic gray matter and focal symptomatic epilepsy, the existence of abnormal hyperexcitability specifically linked to the presence of aberrant connectivity (Shafi et al., 2015). In one of these patients, we could characterize the spatial and temporal origin of a seizure online during a TMS-EEG session and bring evidence that it was spontaneous and unrelated to the stimulation (Vernet et al., 2012a).

References

  • Bashir S, Vernet M, Yoo WK, Mizrahi I, Theoret H, Pascual-Leone A (2012) Changes in cortical plasticity after mild traumatic brain injury. Restor Neurol Neurosci 30:277-282.
  • Bashir S, Perez JM, Horvath JC, Pena-Gomez C, Vernet M, Capia A, Alonso-Alonso M and Pascual-Leone A. (2014) Differential effects of motor cortical excitability and plasticity in young and old individuals: a Transcranial Magnetic Stimulation (TMS) study. Frontiers in Aging Neuroscience. 6(111): 1-13
  • Bashir S, Vernet M, Najib U, Perez J, Alonso-Alonso M, Knobel M, Yoo WK, Edwards D, Pascual-Leone A1 (2016). Enhanced motor function and its neurophysiological correlates after navigated low-frequency repetitive transcranial magnetic stimulation over the contralesional motor cortex in stroke. Restorative Neurology and Neuroscience. 11;34(4):677-89
  • Freitas C, Perez J, Knobel M, Tormos JM, Oberman L, Eldaief M, Bashir S, Vernet M, Pena-Gomez C, Pascual-Leone A (2011) Changes in cortical plasticity across the lifespan. Front Aging Neurosci 3:5.
  • Pascual-Leone A, Freitas C, Oberman L, Horvath JC, Halko M, Eldaief M, Bashir S, Vernet M, Shafi M, Westover B, Vahabzadeh-Hagh AM, Rotenberg A (2011) Characterizing Brain Cortical Plasticity and Network Dynamics Across the Age-Span in Health and Disease with TMS-EEG and TMS-fMRI. Brain Topogr 24:302-315.
  • Pereira AC, Schomer A, Feng W, Najib U, Yoo WK, Vernet M, Alexander MP, Caplan LR, Pascual-Leone A (2012) Anterior Disconnection Syndrome Revisited using Modern Technologies. Neurology 79:290-291.
  • Shafi M, Vernet M, Klooster D, Barnard M, Romatoski K, Westover M, Christodoulou J, Gabrieli J, Whitfield-Gabrieli S, Pascual-Leone A, Chang B (2015) Physiological consequences of abnormal connectivity in a developmental epilepsy. Ann Neurol. 77(3):487-503
  • Teichmann M, Lesoil C, Godard J, Vernet M, Bertrand A, Levy R, Dubois B, Lemoine L, Truong DQ, Bikson M, Kas A, Valero-Cabré A. (2016) Direct current stimulation over the anterior temporal areas boosts semantic processing in primary aphasia. Annals of Neurology. 80(5):693-707
  • Tremblay S, Vernet M, Bashir S, Pascual-Leone A, Théoret H (2015) Theta burst stimulation to characterize changes in brain plasticity following mild traumatic brain injury: a proof-of-principle study. Restor Neurol Neurosci. 33(5):611-20
  • Vernet M, Walker L, Yoo WK, Pascual-Leone A, Chang BS (2012a) EEG onset of a seizure during TMS from a focus independent of the stimulation site. Clin Neurophysiol 123:2106-2108.
  • Vernet M, Bashir S, Enam SF, Kumru H, Pascual-Leone A (2012b) Electrophysiologic Techniques. In: Brain injury medicine: principles and practice (second edition), Second Edition (Zasler N, Zafonte R, Katz D, eds): Demos Medical.
  • Vernet M, Bashir S, Yoo WK, Perez JM, Najib U, Pascual-Leone A (2013) Insights on the neural basis of motor plasticity induced by theta burst stimulation from TMS-EEG. Eur J Neurosci 37:598-606.
  • Vernet M, Bashir S, Yoo WK, Oberman L, Mizrahi I, Ifert-Miller F, Beck CJ, Pascual-Leone A (2014c) Reproducibility of the effects of theta burst stimulation on motor cortical plasticity in healthy participants. Clin Neurophysiol 125:320-326.