Information processing in the brain involves electrical and chemical signals which
are spatially confined at the subcellular level and which occur at the time scale
of milliseconds. While changes of membrane voltage and concentrations of various
intracellular signaling chemicals are well characterized at the level of single cells,
much less experimental data are available on the electrical and chemical signaling
of multiple interacting neurons.
To bridge the gap between our understanding of signals in single neurons and of network
theories, we need to monitor the dynamics of membrane voltage and chemical signals
in neuronal circuits at many sites simultaneously and with high temporal resolution.
this viewpoint, we are developing and applying innovative optical imaging techniques
based on environmental-sensitive fluorescent probes. Membrane voltage, ion concentrations
or second messenger levels modulate the optical properties of such probes. Furthermore,
some of these probes can be genetically encoded and targeted to specific neuronal
compartments. We apply these techniques in the cerebellar and cerebral cortex in
order to understand the principles of the spatio-temporal information flow and its
use-dependent modifications in these brain structures.