Transcranial electrical stimulation (tES) is a non-invasive tool for inducing local and widespread neuroplastic changes in brain networks. The combination of tES with various neuroimaging techniques provides whole brain data on the working mechanisms of tES, in particular on the development of large-scale activation patterns of interconnected neuronal regions induced by tES. Our group focuses on the combined usage of a non-invasive application of transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS) and functional magnetic resonance imaging (fMRI) and on MR spectroscopy.
Functional magnetic resonance imaging (fMRI) is a technique that provides indirect measurements of neural activity. It has the advantages of allowing investigation of brain processes at both superficial and deep brain structures with high spatial resolution and non-invasively. It can be used simultaneously with most transcranial stimulation paradigms thus monitoring on-line changes involved in brain plasticity mechanisms and its manipulation by transcranial stimulation techniques. FMRI can be used to investigate changes either at particular brain structures or in the interaction of brain regions (functional connectivity).
On the other hand, electroencephalography (EEG) measures at the scalp the small changes in electric field providing more direct information of neural activity at high temporal resolution. Consequently, it allows a better measurement of the dynamics of brain processes and its alterations.
Both fMRI and EEG are powerful techniques to compare physiological changes with those related to neurological disorders contributing to a further knowledge of the related pathological alterations and to the development of clinical applications of brain stimulation techniques.
By using diverse techniques such as transcranial stimulation, fMRI and EEG, we can obtain complementary information to help us find the answers to the 'when', 'where' and 'how' of our research questions.
Transcranial magnetic stimulation (TMS) is a non-invasive technique used to map changes in cortical excitability in the motor system. Such transcranial tools are now widely used to investigate processes of neuroplastic induction and their underlying mechanisms in the intact human cortex. Prior to the application of TMS, such investigations were only possible in animal preparations but with the advent of TMS and transcranial stimulation techniques, it has become possible to induce cortical plasticity in the human cortex safely and reversibly. Amongst other transcranial electrical techniques like transcranial alternating current stimulation (tACS), transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS), we are now investigating the effects of near-infrared light (tILS) on the cortex. Each transcranial stimulation method may have different mechanisms of action; membrane polarization, the ability to interfere with ongoing cortical oscillations or directly affecting synaptic modulation. Studies suggest that near-infrared light affects the cellular respiration processes of mitochondria. We aim to evaluate the aftereffects of these methods by applying TMS to measure transcranial stimulation-induced changes in the intact human cortex.
Modulating the excitability of the cerebral cortex using low-intensity electrical stimulation not only offers the possibility of clinical intervention in neurological disorders and conditions, but provides us with a powerful research tool for understanding the workings of the intact human brain.
Due to its involvement in a large variety of cognitive processes, and because it is easily accessible to external brain stimulation techniques, there is now a large, and still growing number of tES studies targeting the frontal cortical areas, such as the dorsolateral prefrontal region. A line of research focuses on the investigation of the role this brain area plays in categorization tasks. Our results suggest that by modulating the excitability of the dorsolateral prefrontal cortex we can alter categorization performance.
Investigating the effects of non-invasive brain stimulation methods on cognitive functions helps us to refine these techniques by fine-tuning the parameters of the interventions for both basic research and clinical purposes.
We are actively looking for participant for our studies in the department. You can contact the researchers directly and enquire about their respective studies and every participation will be rewarded with generous sum of monetary rewards. We are looking forward to hear from you!