Neural micro-stimulations for brain interface - Millisecond imaging of neural responses in the mouse visual cortex

摘要

In order to effectively activate neural circuits in the brain with neural interface, it is essential to understand the properties and the underlying mechanisms of the neural responses induced by electrical stimuli. We have elucidated the spatio-temporal properties of the neural responses to extracellular microstimulation in the mouse visual cortex, utilizing the imaging techniques with voltage-sensitive dye (VSD) and Ca~(2+)-sensitive dye (CaSD), the signals of which are known to mainly reflect postsynaptic potentials (PSPs) and spike firings, respectively. In response to the stimulation to the layer IV of the primary visual cortex (VI), through a micron-tip electrode (glass electrode or the carbon-nanotube-bundle electrode), the suprethreshold CaSD signals and the depolarizing VSD signals were induced around the stimulation site, and synaptically propagated to the layer Will. At the millisecond time resolution, we were able to trace the spatio-temporal sequential propagation of excitatory PSPs and spike firings in the VI circuit. The analyses in the present study provided important information in designing intracortical neural interfaces.