Neural networks on chemically patterned ´cultured probe´ electrode arrays: network growth and activity patterns

A ´cultured probe´ is a hybrid type of neural information transducer or prosthesis, for stimulation and/or recording of neural activity in the brain or the spinal cord (ventral motor region or dorsal sensory region). It consists of a micro electrode array (MEA) on a planar substrate, each electrode being covered and surrounded by a locally confined network of cultured neurons, obtained by chemical patterning of the substrate. The purpose of the cultured cells is that they act as intermediates for collateral sprouts from the in vivo system, thus allowing for an effective and selective neuron electrode interface. As the local neural network will become spontaneously active and has the capability of information processing, one may envisage future applications of these intermediary networks as ´front-end´ signal processors. Two aspects of the development of this kind of cultured probe device are described. First, it is shown how substrates can be chemically modified to confine developing networks, cultured from dissociated rat cortex cells, to the surrounding of an electrode site. Secondly, the paper presents results on neuronal activity in such confined, circular networks and synchronized activity between two such interconnected networks.