Multisuction Electrode Arrays to Investigate Multi-Sensory Integration in Neural Tissue

Abstract

We are studying the neuronal basis of multisensory integration in the medicinal leech, a model animal with a well-characterized and relatively simple nervous system. We aim to discover how the leech's nervous system combines biologically relevant mechanical and visual sensory cues in order to come to a coherent decision about subsequent motion. One goal is to characterize the neural computation that occurs in the leech ganglion, where processing for most described leech behaviors occurs, while visually and mechanically stimulating the leech preparation. Specifically, we will interrogate all the neurons in the ventral side of the ganglion simultaneously at the single cell level by combining multielectrode array (MEA) recordings with voltage sensitive dye (VSD) imaging. The excellent spatial resolution of the VSDs combined with the temporal resolution of MEAs will provide a high level of detail of this computation in the ganglion. We enhanced the MEA design by fabricating optically transparent multi-suction electrode arrays (MSEAs). Each electrode in an array of 60 is constructed around a microfabricated suction pore. Directed suction holds neurons closer to the electrodes and immobilizes tissue without physical distortion, resulting in more stable recordings. The MSEA fabrication protocol builds upon a previously described batch-fabrication technique to make planar patch-clamp electrodes; thus, an entire array of an arbitrary number of pores and devices can be created simultaneously. We are exploiting this by making devices for our collaborators in parallel with our MSEA devices in order to study network behavior in mouse hippocampus slices, and ion channels in giant unilamellar vesicles (GUVs) and mammalian cells.