Author:

Keywords:

Science & Technology, Technology, Life Sciences & Biomedicine, Engineering, Biomedical, Neurosciences, Engineering, Neurosciences & Neurology, flexible polyimide probe, chronic recording, neuron, electrophysiology, microdrive, MOTORIZED MICRODRIVE, BIOCOMPATIBILITY, TECHNOLOGY, ARRAY, ELECTRODES, NEURONS, DEVICE, DRIVE, MICE, Action Potentials, Animals, Brain, Electrodes, Implanted, Locomotion, Microtechnology, Neurons, Rats, Rats, Long-Evans, 0903 Biomedical Engineering, 1103 Clinical Sciences, 1109 Neurosciences, Biomedical Engineering, 3209 Neurosciences, 4003 Biomedical engineering

Abstract:

OBJECTIVE: Long-term electrophysiological recordings of neural activity in freely behaving animals are indispensable to advance the understanding of complex brain function. It is a technical challenge to chronically monitor the detailed activity across multiple distributed brain regions in freely behaving animals over a period of months. Here we present a new implant for inserting multiple flexible polyimide probes into freely behaving rats for monitoring the brain activity over a long time period. APPROACH: This brain implant integrates multiple flexible probes in small micromanipulator devices that ensure free behaviour of the animal. The probes are micromachined and the positioning mechanism is 3D-printed using stereolithography. Each probe is lowered by a screw-driven shuttle and guided through an exit tip before penetrating the rat's brain. MAIN RESULTS: The brain implant consists of 16 individually lowerable flexible polyimide probes that contain 16 embedded electrodes adding up to a total of 256 recording channels. The total travel distance is 8 mm. The assembly time of the device was only one day. The electrode impedance values had a mean of 335 kΩ and sample standard deviation of 107 kΩ after gold plating, excluding outliers. SIGNIFICANCE: For the first time, hyperdrive-assisted insertion of flexible multichannel probes was demonstrated. Local field potentials and neuronal spiking activity from freely behaving rats were recorded over months.