Alexander Thiel, MD
Professor
![Alexander Thiel, MD Alexander Thiel, MD](/neurology-neurosurgery/files/neurology-neurosurgery/styles/medium_focal__220_x_220_/public/08-17521.jpg?itok=_ZC8KOpG)
Since having established his lab at 平特五不中 in 2006, Dr. Thiel is pursuing two major research themes: 1) better understanding the pathophysiology of post-stroke recovery and 2) developing new treatment strategies for patients with post-stroke deficits.
Using molecular imaging methods to measure neuroinflammation in vivo, his group has shown persisting microglia activity after stroke is a risk factor for accelerated neurodegeneration and poor motor recovery (Radlinska 2009 and 2010, Thiel 2010). Combining these molecular PET imaging approaches with diffusion MRI methods, they were the first to demonstrate in stroke patients in vivo that these degenerative changes are not limited to the affected tracts but cause microstructural changes in previously unaffected fibres (Radlinska 2013). His group was the first to image in vivo the morphological correlate of transcallosal disinhibition (Paquette 2011, Thiel 2006), a major mechanism of potential maladaptive neuroplasticity during the recovery phase after stroke (Anglade 2014). Further important progress has been made in establishing image analysis methods for high-resolution 18F-FMZ PET imaging to directly assess cortical neuronal density in vivo (LaFougere 2011 , Funck 2014, 2018), demonstrating a relationship between cortical thickness and the density of neuronal structures in the cortex of normal elderly subjects depends on regional cytoarchitechonics (LaFougere 2011) and can be used to image selective neuronal loss in the penumbra of stroke patients (Funck 2014,2017) and other neurological diseases (Pomares 2017,2019).
Based on the pathophysiological concepts of transcallosal disinhibition, his group used non-invasive brain stimulation methods, to downregulate cerebral activity in the unaffected hemisphere to re-establish the inter-hemispheric dominance pattern prior to the brain lesion (Weiduschat 2011). Using rTMS in subacute patients with aphasia a better and faster recovery was achieved and, using functional imaging, they were also able to demonstrate a normalization of brain activations patterns consistent with a reversal of transcallosal disinhibition (Thiel 2013, Rubi-Fessen 2015). The promising results of these preliminary studies led to NORTHSTAR, the first international multicenter trial on non-invasive brain stimulation for aphasia recovery (Thiel 2015). This study has finished recruitment end of August 2018. Experience with NORTHSTAR led to the CanStim initiative, a national platform for brain stimulation trials in stroke. In addition to non-invasive brain stimulation, his group translated robot-assisted training approaches, developed by Dr. Ostry鈥檚 group into rehabilitation treatment for stroke patients (Vhadat 2018).
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Neuroplasticity, stroke recovery, PET and MR imaging, non-invasive brain stimulation