A novel high electrode count spike recording array using an 81,920 pixel transimpedance amplifier-based imaging chip.

Area of Science:

• Neuroscience
• Bioengineering
• Signal Processing

Background:

• Current microelectrode arrays (60-100 electrodes) limit the study of neuronal function in large brain areas.
• Higher density, larger area recording arrays are crucial for understanding complex neural circuits.

Purpose of the Study:

• To introduce a novel high electrode count picocurrent imaging array (PIA) for advanced neural recordings.
• To demonstrate the PIA's capability for high-speed, high-fidelity recording of neuronal biopotentials.

Main Methods:

• Adapted an 81,920-pixel camera chip (Indigo ISC9809) for neural recording by bonding it to microwire glass.
• Integrated low-noise transimpedance amplifiers (∼0.32 pA rms) at each pixel for high signal-to-noise ratio biocurrent recording.
• Utilized selective subarray sampling for high-speed recording of neural activity.

Main Results:

• Achieved an inter-electrode pixel spacing of 30 μm for high-density recordings.
• Recorded extracellular biocurrents of rabbit retinal ganglion cell spikes at 7.2 kHz sampling rates.
• Captured full array local electroretinogram currents at 100 Hz frame rates, demonstrating broad applicability.

Conclusions:

• The novel PIA offers a significant advancement for large-scale neural recordings.
• Its high density, speed, and signal quality are suitable for studying complex neural systems.
• Future iterations could cover 1cm areas, acquiring data from 1024 electrodes simultaneously at high sampling rates.