A wireless and batteryless neural headstage with optical stimulation and electrophysiological recording

Abstract

This paper presents a miniature Optogenetics headstage for wirelessly stimulating the brain of rodents with an implanted LED while recording electrophysiological data from a two-channel custom readout. The headstage is powered wirelessly using an inductive link, and is built using inexpensive commercial off-the-shelf electronic components, including a RF microcontroller and a printed antenna. This device has the capability to drive one light-stimulating LED and, at the same time, capture and send back neural signals recorded from two microelectrode readout channels. Light stimulation uses flexible patterns that allow for easy tuning of light intensity and stimulation periods. For driving the LED, a low-pass filtered digitally-generated PWM signal is employed for providing a flexible pulse generation method that alleviates the need for D/A converters. The proposed device can be powered wirelessly into an animal chamber using inductive energy transfer, which enables compact, light-weight and cost-effective smart animal research systems. The device dimensions are 15×25×17 mm; it weighs 7.4 grams and has a data transmission range of more than 2 meters. Different types of LEDs with different power consumptions can be used for this system. The power consumption of the system without the LED is 94.52 mW.

Towards a wireless optical stimulation system for long term in-vivo experiments

“…However, such devices are most often tethered to a remote power and/or light source, which leads to several limitations caused by cables like sheer stress, prohibitive weight and increased risks of infection [13]. Wireless head mountable optical stimulators are therefore highly sought for this application [4], [5], [14][15][16]. However, using a small battery for driving an embedded optical stimulation source is not practical since This LEDs or VECSELs require high power that is only available from a large and usually cumbersome battery.…”

“…These devices have a wide range of applications such as health monitoring, disease treatment and biomimetic prosthesis. Direct neuronal stimulation using electrical or optical means is the basis of several new emerging treatments and neuroprostheses [1][2][3][4][5][6][7]. Studying elicited neuronal activity through direct neuronal stimulation in freely moving animals, with observable behavior, is critical for advancing our understanding of the brain [8,9].…”

A Wireless Headstage for Combined Optogenetics and Multichannel Electrophysiological Recording

“…Recently, optogenetics has been used to carry various behavioral experiments with freely behaving rodents, especially mice [1]- [3]. Light activation/inhibition is commonly achieved using laser or LEDcoupled optical fibers [4] that illuminate the targeted neural cells.…”

Toward biomaterial-based implantable photonic devices

“…To solve these challenges, wireless and micro-scaled LEDs have been developed using wireless power transfer and micro-scaled circuit designs. A major consideration in the design of wireless LEDs is power supply, which is typically transmitted through RF energy harvesting [169,173] or inductive power [174]. In contrast, wirelessly controlled LEDs use rechargeable batteries and communicate via RFs [173].…”

“…The average output intensity of wireless LEDs is typically~10 mW/mm 2 [169,173], which exceeds (up to 10-fold) the minimum intensity necessary to stimulate rhodopsins. Wireless LEDs have been directly implanted to deep brain tissues in mice [169,174,175]. Flexible and injectable µ-LEDs, with dimensions 0.1 × 1 × 1 mm 3 that are less than 1000th the size of conventional LEDs, are suited for chronic use in vivo because of their small sizes, effective thermal management, and reduced tissue damage during the insertion process [169].…”