Using Microelectrode Arrays for Cerebral Applications

The fundamental understanding of cerebral systems and associated diseases relies on the electrical recording of single neuron activity. This requires in vivo interfacing with neurons using micrometer-scale electrodes. Traditionally, this challenging task is being performed using: single wire electrodes, probes containing small ensembles of electrodes or, more recently, multi-electrode arrays. These electrode arrangements have the potential to gather signals in three-dimensional space and to provide important laminar information. However, the types of arrays that have been proposed so far are either restricted to sampling in a given plane or have difficulty in collecting data in complex regions, such as those found in highly convoluted cortices. Moreover, state-of-the-art micro-electrode systems are not (yet) suitable for obtaining highly stable signals over extended recording periods. In some cases, the probes are just too bulky to follow cortical motion in chronic applications. Also, the damage inflicted to tissue and the way tissue responds to the presence of a foreign body are presently restrictive to chronic neural recordings. Such a chronic use is, however, highly needed, since it allows the study of changes in population activity at single neuron level and at the interaction level with learning, memory and training.