Pharmacological Characterisation and Modulation of Neuroplasticity in Humans

M.   A.   Nitsche; D.      Liebetanz; W.      Paulus; F.      Tergau

doi:10.2174/1570159054368268

Abstract

Neuroplasticity is defined as enduring modification, both functional and/or structural, within the central nervous system. The respective processes are thought to be of crucial importance for learning, but also for more general adaptive processes in response to environmental changes or consequences of brain lesions. Moreover, it is hypothesized that neuroplasticity is involved in diseases displaying altered central nervous activity. Exploring its physiological foundations is thus of crucial importance for understanding the functional properties of the brain. Until now, research in this area was primarily restricted to animal research, which has already afforded important insights into the physiological and pharmacological foundations of neuroplasticity. In recent years, however, an arsenal of neurophysiological tools has been developed which induces or modulates neuroplastic processes, even in humans. Combining these techniques with pharmacological interventions has already proved helpful and will, on the one hand, be of future importance in understanding the mode of action of these instruments and provide information about the involvement of neurotransmitters, and neuromodulators in human neuroplasticity on the other. It has been shown that, like in animal experiments, NMDA receptor modulation is essential for the induction of neuroplasticity in the human brain, whereas GABAergic activity seems to inhibit it. These results, among others, suggest a similarity between long-term depression and potentiation as induced in animals and neuroplastic processes in humans. Moreover, equivalent to studies performed in animals, monoaminergic and cholinergic neuromodulation controls the consolidation of human neuroplasticity. Although lots of work has still to be done to fully understand these processes and their functional importance, the current state of research already offers important insights into human brain function and may help in future to develop appropriate therapeutic regimens, in which neuroplastic changes are involved or required to treat diseases of the central nervous system.

Keywords: neuroplasticity, humans, neuropharmacology, neurophysiology, brain stimulation, transcranial magnetic stimulation, ltp, ltd