Extracellular recording of \textit{Hirudo medicinalis} neurons using high density, nanocoax neurointerface array

We describe the development of a nanocoax-based neuroelectronic array with submicron pixelation with potential for recording and stimulation with high spatial and temporal resolution. Our device is composed of an array of nanoscale open-ended coaxial electrodes addressed in either a group or individual configuration. As a neuroelectronic interface, our device is characterized by noninvasive real-time coupling to the ganglion sac located along the main nerve cord of the \textit{Hirudo medicinalis}. This allows for extracellular recording of interneural synaptic activity, while also showing the capability of actuating precisely-localized stimulation (faradaic regime). We report on initial results from measurements of electrical signals associated with induced and spontaneous synapse firing in pre- and post-synaptic somata.