elektrodearrays

An electrode array is a configuration that groups multiple electrodes into a single device to record electrical activity from or deliver electrical stimulation to biological tissue. Arrays are used to capture spatially distributed signals, enabling simultaneous measurements across many sites or targeted stimulation of specific regions.

Electrode arrays can be broadly categorized as invasive, non-invasive, or partially invasive. Invasive arrays are implanted into or across neural tissue, providing high spatial and temporal resolution. Examples include intracortical microelectrode arrays such as Utah-style silicon arrays and multi-shank Michigan probes, as well as flexible polymer or carbon-based shanks designed to reduce tissue damage. Non-invasive arrays include surface electrode grids used for electrocorticography (ECoG) or scalp EEG electrode caps, which offer easier deployment but lower spatial resolution. There are also semi-invasive approaches like implanted depth electrodes for seizure monitoring.

Construction and materials vary with use. Common device substrates include silicon or polymer foams, with conductive elements made from platinum-iridium, gold, or carbon fibers. Coatings such as PEDOT or iridium oxide can improve impedance and charge transfer. Fabrication relies on microfabrication, photolithography, and microassembly techniques to create densely packed, individually addressable channels.

Applications span neuroscience research, brain-computer interfaces, and clinical diagnostics. They are used to map functional areas, study neural coding, control assistive devices, and guide surgical planning. In sensory prosthetics, electrode arrays enable restoration of function, as in cochlear implant electrodes or somatosensory interfaces.

Challenges include biocompatibility, foreign-body response, scar tissue formation, and long-term signal stability. Advances focus on higher density, flexible and biocompatible materials, wireless data transmission, and combined electrical and optical modalities.

See also: neural probes, brain-computer interfaces, electrocorticography, neural recording technologies.