ChroMOS: a "microwire-like" CMOS neural probe for chronic neural recordings in mice.

Achieving stable and continuous monitoring of signals of numerous single neurons in the brain faces the conflicting challenge of increasing the microelectrode count while minimizing cross-sectional shank dimensions to reduce tissue damage, foreign-body-reaction and maintain signal quality. Passive probes need to route each microelectrode individually to external electronics, thus increasing shank size and tissue-damage as the number of electrodes grows. Active complementary metal-oxide-semiconductor (CMOS) probes overcome the limitation in electrode count and density with on-probe frontend, addressing and multiplexing circuits, but current probes have relatively large shank widths of 70 - 100 μm.

Simultaneous high-density 512-channel SiNAPS electrical recordings and optogenetics.

The experimental use of CMOS high-density neural probes enables the wide field observation of the electrical activity of neural circuits at the resolution of single neurons. Optogenetic light stimulation allows to control and modulate the activity of neural cells, in a genetically selective manner. The combination of these techniques can be a powerful approach for investigating mechanisms of brain diseases and of information processing in the brain.

Force Measurements to Advance the Design and Implantation of CMOS-Based Neural Probes.

Objective: Tissue penetrating active neural probes provide large and densely packed microelectrode arrays for the fine-grained investigation of brain circuits and for advancing brain-machine interfaces (BMIs). To improve the electrical interfacing performances of such stiff silicon devices, which typically elicit a vigorous foreign body reaction (FBR), here we perform insertion force measurements and derive probe layout and implantation procedure optimizations.

Methods: We performed in-vivo insertion force measurements to evaluate the impact of probe design and implantation speed on mechanically induced trauma and iatrogenic injury.

Multi-Shank 1024 Channels Active SiNAPS Probe for Large Multi-Regional Topographical Electrophysiological Mapping of Neural Dynamics.

Implantable active dense CMOS neural probes unlock the possibility of spatiotemporally resolving the activity of hundreds of single neurons in multiple brain circuits to investigate brain dynamics. Mapping neural dynamics in brain circuits with anatomical structures spanning several millimeters, however, remains challenging. Here, a CMOS neural probe advancing lateral sampling for mapping intracortical neural dynamics (both LFPs and spikes) in awake, behaving mice from an area >4 mm is demonstrated.

Multi-shank 1024 channels active SiNAPS probe for large multi-regional topographical electrophysiological mapping of neural dynamics.

Implantable active dense CMOS neural probes unlock the possibility of spatiotemporally resolving the activity of hundreds of single neurons in multiple brain circuits to investigate brain dynamics. Mapping neural dynamics in brain circuits with anatomical structures spanning several millimeters, however, remains challenging. Here, we demonstrate the first CMOS neural probe for mapping intracortical neural dynamics (both LFPs and spikes) in awake, behaving mice from an area >4 mm.

Advancing the interfacing performances of chronically implantable neural probes in the era of CMOS neuroelectronics.

Tissue penetrating microelectrode neural probes can record electrophysiological brain signals at resolutions down to single neurons, making them invaluable tools for neuroscience research and Brain-Computer-Interfaces (BCIs). The known gradual decrease of their electrical interfacing performances in chronic settings, however, remains a major challenge. A key factor leading to such decay is Foreign Body Reaction (FBR), which is the cascade of biological responses that occurs in the brain in the presence of a tissue damaging artificial device.

Astrocytes actively support long-range molecular clock synchronization of segregated neuronal populations.

In mammals, the suprachiasmatic nucleus of the hypothalamus is the master circadian pacemaker that synchronizes the clocks in the central nervous system and periphery, thus orchestrating rhythms throughout the body. However, little is known about how so many cellular clocks within and across brain circuits can be effectively synchronized. In this work, we investigated the implication of two possible pathways: (i) astrocytes-mediated synchronization and (ii) neuronal paracrine factors-mediated synchronization.

Integrated Micro-Devices for a Lab-in-Organoid Technology Platform: Current Status and Future Perspectives.

Advancements in stem cell technology together with an improved understanding of organogenesis have enabled new routes that exploit cell-autonomous self-organization responses of adult stem cells (ASCs) and homogenous pluripotent stem cells (PSCs) to grow complex, three-dimensional (3D), mini-organ like structures on demand, the so-called organoids. Conventional optical and electrical neurophysiological techniques to acquire functional data from brain organoids, however, are not adequate for chronic recordings of neural activity from these model systems, and are not ideal approaches for throughput screenings applied to drug discovery. To overcome these issues, new emerging approaches aim at fusing sensing mechanisms and/or actuating artificial devices within organoids.

PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics.

Minimally invasive medical devices can greatly benefit from Narrow Band Imaging (NBI) diagnostic capabilities, as different wavelengths allow penetration of distinct layers of the gastrointestinal tract mucosa, improving diagnostic accuracy and targeting different pathologies. An important performance parameter is the light intensity at a given power consumption of the medical device. A method to increase the illumination intensity in the NBI diagnostic technique was developed and applied to minimally invasive medical devices (e.

LED Optrode with Integrated Temperature Sensing for Optogenetics.

In optogenetic studies, the brain is exposed to high-power light sources and inadequate power density or exposure time can cause cell damage from overheating (typically temperature increasing of 2 ∘ C). In order to overcome overheating issues in optogenetics, this paper presents a neural tool capable of assessing tissue temperature over time, combined with the capability of electrical recording and optical stimulation. A silicon-based 8 mm long probe was manufactured to reach deep neural structures.

High-selectivity neural probe based on a Fabry-Perot optical filter and a CMOS silicon photodiodes array at visible wavelengths.

This paper presents a silicon neural probe with a high-selectivity optical readout function and light emitting diodes for neurons photostimulation and fluorophore excitation. A high-selectivity Fabry-Perot optical filter on the top of a CMOS silicon photodiodes array can read the emitted fluorescence, which indicates the neurons physiological state. The design, fabrication, and characterization of the optical filter are presented.