Brain stimulation in the age of "light": Controlling and steering cortical cellular electrophysiology for future smart neuroprosthetics employing Optogenetics.

The brain learns by altering the synaptic connections between neurons. At the level of neural networks, the "state" is thus represented by a connectivity profile. Electrical neuronal activity may however alter such a profile by inducing changes in the number and the efficacy of synapses, a phenomenon collectively known as activity-dependent synaptic plasticity. In turn, the wiring of a network affects the activity that it can exhibit. The interaction between activity and connectivity results in a balance, which is susceptible to disturbance by external inputs to the new network. With this project I want to explore how the state of a network, developing ex vivo on microelectrode arrays, can be modulated and controlled by stimulation. This will be mediated by light-sensitive ion channels, genetically engineered to be expressed in certain neurons, and activated by exposing them to light. This technique, known as Optogenetics, is advantageous to stimulate extremely specific, allowing both a fine control in time and in space. By operating in real-time, the stimulation will also take the dynamic state of the network into account. The result is a so-called closed-loop: the stimulation affects the neuronal activity, which in turn affects future stimulation. Thus, a closed-loop approach is central to interact efficiently with neuronal tissue. The result of this study will contribute to our knowledge of the properties of the interfacing of electronic devices with artificial in vitro brain preparations, such as in future brain prostheses.

Keywords:NEURONAL MICROCIRCUITS, MULTI ELECTRODE ARRAY, OPTOGENETICS, NEUROPHYSIOLOGY

Disciplines:Neurosciences, Biological and physiological psychology, Cognitive science and intelligent systems, Developmental psychology and ageing