Year: 2011
Type: dissertation
Abstract: Penetrating neural probe technologies provide researchers with the capability to stimulate and record chemical and electrical signals in the brain. While present technology has yielded significant insight into the function of the brain, this technology is limited in a number of ways. Although recent breakthroughs have enabled the fabrication of three dimensional probes with hundreds of recording sites, information processing strategies to utilize this new technology are currently unrealized. Moreover, increasing channel numbers creates larger devices and concurrently highlights data processing and classification problems. Analyzing more channels not only takes more time, but also precludes many of the user-directed sorting and analysis schemes that are commonly used. We have addressed these issues by developing and testing novel information processing strategies to take full advantage of the three dimensional probe as well as evaluating site modifications to revitalize recording sites. In the first study, we developed an efficient, automated spike sorting package using MATLAB software incorporating various techniques to more efficiently analyze large volumes of data from high channel neural probes. Overall algorithm performance has been evaluated with respect to current commercially available alternatives and performance has been comparable and objective. The algorithm will be provided online for free distribution. In the second study, we developed a method to determine neural morphology by utilizing multichannel simultaneous electrophysiological recordings. Our technique identifies dendritic contributions to the potential recorded on distant electrode sites using event-triggered averaging from known firing times of isolated unit potentials to provide additional information about the morphology of recorded neurons in the space around the array. In the third study, we have investigated the use of PEDOT to lower the impedance of small, gold recording electrodes with initial impedances outside the effective recording range. Smaller electrode sites enable more densely packed arrays and promote smaller overall probe designs. In the final study, we have validated a 3D probe technology consisting of 16 silicon shanks in a 4x4 grid arrangement with four electrode sites per shank. Using this new technology, we have generated one of the first simultaneous, 3D intra-cortical, electrophysiological maps of primary auditory cortex responses.
Author: Nicholas B. Langhals
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W40402425