Development and Design

The Utah Array is a bed-of-nails silicon microelectrode design developed at the University of Utah by Richard Normann’s bioengineering lab. The penetrating-array concept was pioneered by Normann in the 1980s, with the foundational glass/silicon composite intracortical electrode array described in a 1992 Annals of Biomedical Engineering paper. The array consists of 100 small-diameter silicon microneedles arranged in a 10-by-10 grid with 400 µm spacing, each electrode penetrating approximately 1.5 mm into the cortex. The name derives from the appearance of the densely-packed electrode tips resembling nails in a bed. In typical research and clinical use, 96 of the 100 channels are wired (four corners reserved for cabling).

Signal Quality Advantages

The intracortical penetrating approach provides superior signal quality compared to surface electrodes or non-invasive methods. Each electrode records activity from individual neurons within a few hundred micrometers, enabling identification of single-unit action potentials rather than broader population signals. This high spatial resolution directly enables more accurate neural decoding.

Clinical adoption

In 2004, Matthew Nagle became the first person to use a Utah Array BCI to control a cursor with thought alone, in the inaugural BrainGate clinical trial. The Utah Array remains in clinical use today through BrainGate, Blackrock Neurotech (the commercial owner of the Utah Array IP and manufacturer of the NeuroPort Electrode Array based on it), and the high-density 256-electrode UC Davis speech BCI work (which uses four 64-electrode arrays of related Utah-style intracortical architecture).

Importantly, Neuralink does NOT use the Utah Array. Neuralink’s N1 implant uses 1,024 electrodes distributed across 64 ultra-thin flexible polymer threads (~5 µm wide each), inserted individually by the R1 surgical robot. The Utah Array (rigid silicon needles in a fixed bed) and the Neuralink thread system are fundamentally different electrode architectures. Other companies pursuing penetrating intracortical recording with flexible-substrate alternatives include Paradromics (Connexus) and a growing list of next-generation startups.

Chronic Implantation Limitations

A significant limitation of the rigid Utah Array geometry is that chronic intracortical implantation triggers glial scarring around the electrodes, causing gradual signal degradation over months and years. The foreign-body response to the electrode material and mechanical mismatch with brain tissue creates a hostile tissue environment that limits long-term device function.

Evolutionary Advances

Companies including Precision Neuroscience (thin-film surface arrays), Paradromics (high-density penetrating arrays on flexible substrates), Neurosoft Bioelectronics (soft stretchable cortical arrays), and Neuralink (flexible polymer threads) are developing alternative electrode geometries to address chronic implant limitations while maintaining the signal quality advantages of cortex-adjacent or cortex-penetrating recording. The Utah Array remains the historical reference standard against which competing approaches are measured.