Cellular-scale silicon probes for high-density, precisely-localized neurophysiology

Abstract

Neural implants with large numbers of electrodes have become an important tool for examining brain functions. However, these devices typically displace a large intracranial volume compared to the neurons they record. This large size limits the density of implants, provokes tissue reactions that degrade chronic performance, and impedes the ability to accurately visualize recording sites within intact circuits. Here we report nextgeneration silicon-based neural probes at cellular-scale (5x10µm cross-section), with ultra-high-density packing (as little as 66µm between shanks) and 64 or 256 closely-spaced recording sites per probe. We show that these probes can be inserted into superficial or deep brain structures and maintain high-quality spike recordings in freely behaving rats for many weeks. Finally, we demonstrate a slice-in-place approach for the precise registration of recording sites relative to nearby neurons and anatomical features, including striatal µ-opioid receptor patches.This scalable technology provides a valuable tool for examining information processing within neural circuits, and potentially for human brain-machine interfaces.

The Degree of Nesting between Spindles and Slow Oscillations Modulates Neural Synchrony

“…We recorded extracellular neural activity using tungsten microwire electrode arrays (n = 2 rats, Tucker-Davis Technologies), tetrodes (n = 1 rat, NeuroNexus), and custom probes (n = 1 rat) (Egert et al, 2018). We implanted arrays targeted to layer 5 of (;1.5 mm) the caudal forelimb area of the M1, centered at 3-4 mm lateral, 0.5 mm anterior to bregma.…”

Neuropixels 2.0: A miniaturized high-density probe for stable, long-term brain recordings

“…Recording individual neurons stably over weeks or months is critical to understand processes that evolve over time, such as learning, memory, and plasticity. To provide such stable recordings and minimize tissue damage, considerable effort has been devoted to developing probes that are flexible (28)(29)(30) and/or <10 µm in size (31)(32)(33)(34), but these approaches make insertion difficult and limit the number of recording sites per inserted shank. Moreover, high quality signals can be recorded for more than eight weeks even with relatively rigid and large devices such as wire tetrodes (35,36), Utah arrays (37,38), traditional silicon probes (39)(40)(41), and Neuropixels probes (6,25,42).…”

Neuropixels 2.0: A miniaturized high-density probe for stable, long-term brain recordings

“…Recording individual neurons stably over weeks or months is critical for studying the neural basis of processes that evolve over time, such as learning and memory, the dynamics of population coding, and neural plasticity. To provide prolonged high quality recordings, considerable effort has been devoted to the development of recording devices that are flexible (Fu et al, 2017;Chung et al, 2019;Musk, 2019) and/or <10 µm in size (Guitchounts et al, 2013;Luan et al, 2017;Egert et al, 2020;Welle et al, 2020) to minimize damage to tissue, but these approaches make insertion difficult and do not scale to large numbers of recording sites per inserted shank. Moreover, high quality signals can be recorded for more than eight weeks even with relatively rigid and larger devices such as wire tetrodes (Recce and O'Keefe, 1989;Dhawale et al, 2017), Utah arrays (Maynard et al, 1997;Chestek et al, 2011), and silicon probes (Okun et al, 2016;Jun et al, 2017;Muthmann et al, 2020;Schoonover et al, 2020).…”