Berdondini, L. | Search bioRxiv

bioRxiv2025

High-density, Identified Cell Recordings from Motor Cortex of Awake Behaving Macaques using 1024-channel SiNAPS-NHP Probes

Objective/BackgroundAcquiring bioelectric signals from many single neurons in primate brain remains challenging. Chronic implants offer a reasonable channel count ([~]100) but sample only a small, fixed region of the cortex. Acutely inserted electrodes can sample from a wider region by making new penetrations each day. The aim of this study was to develop an active dense CMOS probe and experimental procedures to demonstrate acute large-scale single unit recordings from behaving monkeys. MethodsA single-shank CMOS probe was specifically designed for intracortical macaque recordings. The device is based on SiNAPS technology, with additional multiplexing circuits to minimize output lines. Synchronous sampling at 20 kHz/channel from >2k electrode-pixels is achieved with multiple probe systems. Experiments were performed in behaving macaques, achieving multiple day insertions in the motor cortex. Methods were developed to extract spontaneous spiking times of antidromically-identified neurons. ResultsThe probe (10.7 mm in length, 158 m in width, 50 m in thickness) provides a regular array of 1024 electrodes (14 x 14 m2) arranged in 4 columns with an interelectrode pitch of 30 m. Dural penetration is eased by a small pilot hole; the optimized insertion procedure allows recordings from many different sites. Some cells were identified by antidromic activation as pyramidal tract neurons, which project to the spinal cord. ConclusionThis probe configuration can reach the anterior bank of the central sulcus, which contains many corticospinal cells that connect directly to motoneurons. SignificanceThis study is an important advance in the toolkit of primate neurophysiology.

neuroscience↗

bioRxiv2019

Multi-shanks SiNAPS Active Pixel Sensor CMOSprobe: 1024 simultaneously recording channels for high-density intracortical brain mapping

The advent of implantable active dense CMOS neural probes opened a new era for electrophysiology in neuroscience. These single shank electrode arrays, and the emerging tailored analysis tools, provide for the first time to neuroscientists the neurotechnology means to spatiotemporally resolve the activity of hundreds of different single-neurons in multiple vertically aligned brain structures. However, while these unprecedented experimental capabilities to study columnar brain properties are a big leap forward in neuroscience, there is the need to spatially distribute electrodes also horizontally. Closely spacing and consistently placing in well-defined geometrical arrangement multiple isolated single-shank probes is methodologically and economically impractical. Here, we present the first high-density CMOS neural probe with multiple shanks integrating thousands of closely spaced and simultaneously recording microelectrodes to map neural activity across 2D lattice. Taking advantage from the high-modularity of our electrode-pixels-based SiNAPS technology, we realized a four shanks active dense probe with 256 electrode-pixels/shank and a pitch of 28 {micro}m, for a total of 1024 simultaneously recording channels. The achieved performances allow for full-band, whole-array read-outs at 25 kHz/channel, show a measured input referred noise in the action potential band (300-7000 Hz) of 6.5 {+/-} 2.1{micro}VRMS, and a power consumption <6 {micro}W/electrode-pixel. Preliminary recordings in awake behaving mice demonstrated the capability of multi-shanks SiNAPS probes to simultaneously record neural activity (both LFPs and spikes) from a brain area >6 mm2, spanning cortical, hippocampal and thalamic regions. High-density 2D array enables combining large population unit recording across distributed networks with precise intra- and interlaminar/nuclear mapping of the oscillatory dynamics. These results pave the way to a new generation of high-density and extremely compact multi-shanks CMOS-probes with tunable layouts for electrophysiological mapping of brain activity at the single-neurons resolution.

bioengineering↗