Inaugural Lecture // Neuromodulation of the cerebral cortex – a tale of 2000 years

Stimulating the human brain to enhance brain function and behaviour, and especially to treat patients suffering from neuropsychiatric diseases is a dream and goal in clinical and behavioural neuroscience since more than 2000 years. First reports applying non-invasive electrical stimulation delivered by discharges of electro-fish to the brain are dating back to 50 AC (Scribonius largus, 43-48 AC) and are reported over the centuries. Technological developments of non-invasive brain stimulation by means of transcranial magnetic or transcranial electric stimulation in the last 30 years and the better understanding of them, paved the way to apply brain stimulation in a focal, controlled and safe way allowing to modulate neuro-physiological parameters, brain functioning and behaviour. Based on these developments and due to their safe and relatively easy application, these methods gained recently large interest in different domains of neuroscience from neuro-enhancement of motor learning or cognition, to improve gaming performance to counteract results of cognitive aging. Even more, since 10 years, they are applied in neuropsychiatric disorders to treat these diseases or improve the recovery from them.
Although non-invasive brain stimulation is a powerful tool and first proof-of-principle results are very promising, it became more and more clear that the application and its underlying mechanisms are not that simple, but far more complex and that the induced neuro-modulatory effects are heterogeneous with responders and non-responders with still a relevant lack of understanding, which factors exactly determine the magnitude and heterogeneity of responses. Currently, there are strong efforts to better understand the mechanisms of these technologies, the factors of the individual brain influencing the response to the stimulation and developments to apply brain stimulation in an individualized fashion with the long-term goal of state-dependent and closed-loop applications.
This inaugural lecture will provide an historical overview of brain stimulation, summarize the current state of the art, will discuss the limitation and opportunities of the methods, ethical considerations especially the use of it in a lay environment and at the end an outlook towards future developments of this field, especially for translational clinical neuroscience and interventional neurology.