title: Chronic recording capability of the Utah Intracortical Electrode Array in cat sensory cortex.
abstract: The Utah Intracortical Electrode Array (UIEA) is an array of 100 penetrating silicon microelectrodes designed to focally electrically stimulate or record neurons residing in a single layer up to 1.5 mm beneath the surface of the cerebral cortex. Apart from its use as a unique tool to study parallel processing in the central nervous system, this array could form the platform for a cortical neuroprosthetic system. Although the UIEA has been used extensively in acute neural recording and stimulation experiments, its long-term performance in a chronic application has yet to be demonstrated. As an initial investigation into the feasibility of long-term cortical recording with an array of microelectrodes, we have hard-wired a subset of 11 electrodes of the UIEA to a percutaneous connector. This chronic UIEA assembly was then implanted into the cerebral cortices of ten cats for durations ranging from 2 to 13 months; over which time, both random and stimulus-evoked single and multiple unit action potentials were periodically recorded. On average, after a 6-month implant period, 60% of implanted arrays could still record some type of activity. Post-sacrifice dissections revealed a fibrous encapsulation of the UIEA. Although most implanted cortex was histologically normal, evidence of a chronic astroglial response was seen in a few cases. The results of the reported experiments indicate that the UIEA can be successfully used for limited times in a chronic recording application.
authors.affiliation: Department of Optometry and Visual Sciences, University of Manchester Institute of Science and Technology, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Rousche
authors.forename: R A
authors.initials: RA
authors.lastname: Normann
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002415:Cats; D017097:Electric Impedance; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D008839:Microelectrodes; D013003:Somatosensory Cortex / Q000502:physiology*; D014589:Utah