Doric Lenses (Canada)

The demonstration will presents a battery powered multichannel wireless optogenetic headstage providing neural recording and optical stimulation capabilities simultaneously. The proposed headstage, which is entirely built using commercial off-the-shelf components, includes 32 electrophysiological recording channels and up to 32 high-power optical stimulation channels. It can process 32 neuronal signals in real-time with high compression ratio using an FPGA performing spike detection and data compression in-situ for fitting 32 channels over a low-power 2.4-GHz ISM data link (compression ratio > 500), hence greatly decreasing power and complexity. The presented headstage is small and lightweight enough for enabling optogenetic in-vivo experiments with freely moving transgenic rodents.

This paper presents the in vivo performances of a resource-optimized digital action potential (AP) detector featuring an adaptive threshold based on a new Sigma-delta control loop. The proposed AP detector is optimized for utilizing low hardware resources, which makes it suitable for real-time implementation on most common low-power microcontroller units (MCU). The adaptive threshold is calculated using a digital control loop based on a Sigma-delta modulator that precisely estimates the standard deviation of the neuronal signal amplitude. The detector was demonstrated using a common MCU from MSP430 family, incorporated into a small wireless platform for combined optogenetics and neura recording. The system has been fully characterized experimentally within in vivo experiments on a freely-moving transgenic mouse expressing ChannelRhodospin (Thy1::ChR2-YFP line4. The results demonstrate that the proposed AP detector can be used to achieve overall data reduction ratios above 11 hen transmitting only the detected APs. A comparison of the obtained results with other thresholding approaches shows that the pr posed detector provides similar performances to those significantly more resource demanding approaches.

This paper presents a multichannel wireless op-togenetic headstage providing neural recording and optical stimulation capabilities simultaneously. The proposed headstage, which is entirely built using commercial off-the-shelf components, includes 32 electrophysiological recording channels and up to 32 high-power optical stimulation channels. It can process 32 neuronal signals in real-time with high compression ratio using an embedded digital signal processor performing spike detection and data compression in-situ. The presented headstage is small and lightweight rendering it suitable for conducting in-vivo experiments with freely moving transgenic rodents. We report results obtained from in-vivo experiments showing that the proposed wireless headstage can collect, detect and compress the microvolts amplitude neuronal signals evoked by light stimulation with a high averaged peak-signal-to-noise ratio of 22.4 dB and a high averaged signal-to-noise distortion ratio of 17.0 dB. The design of this headstage is using a rigid-flex printed circuit board, resulting into a lightweight (2.8 g) and compact device (17×18×10 mm3).

We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm2 at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals.