Browsing by Subject "Peripheral electrode"

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Ultraflexible nanoelectronic thread application in central and peripheral nervous systems
(2020-02-05) Li, Xue, M.S. in Engineering; Xie, Chong, Ph. D.
Implanted electrodes have long been used to interface with the nervous system in vivo, but their recording efficacy and biocompatibility were limited by the mechanical mismatch between the electrode and the tissue. The development of the Nanoelectronic thread (NET) probe solves the problem by using polymer material with a cellular dimension that realized glial scare-free interface with high-quality chronic unit recording over months. In this work, I further explore the application of the NET electrode in both central and peripheral nervous systems. In the central nervous system, neural circuits span diverse spatial scales: they consist of nearby clusters of neurons as well as neurons distributed across multiple brain areas. Technically, electrical recording by implanted electrodes allows for millisecond resolution detection of individual neuron activity, but can typically only sample a small portion of all neurons involved in a circuit. Optical measurements of neuronal activity, in contrast, permit high spatial-resolution mapping of a large number of neurons, but typically penetrate < 1 mm in depth and have limited temporal resolution. It is therefore desired to combine the complementary advantages of optical and electrical measurements. Here I demonstrate a method that combines ultraflexible neural electrodes with a nearly-cortex-wide polymer cranial window to enable large-scale recording from individual neurons and simultaneous optical imaging in the neocortex for longitudinal studies. We show that this setting flexibly allows for concurrent implementation of multiple neural recording and modulation techniques, including spatially resolved recordings at multiple regions and in deep structures, epi-fluorescence imaging across the cortex, two-photon imaging at multiple cortical regions, and optogenetics. In the peripheral nervous system, many efforts have been made towards the development of a reliable neural interface dependent neuroprosthesis. However, the development has long been limited by the performance of the neural interface which lacks stability, chronic recording capability, high specificity, and high channel count. In this work, I developed two types of peripheral NET (p-NET) probe to potentially achieve chronic stable recording with high specificity and high channel count in the peripheral nervous system