In the past 50 years there has been an explosion of interest in the development of technologies whose end goal is to connect the human brain and/or nervous system directly to computers. Once the subject of science fiction, the technologies necessary to accomplish this goal are rapidly becoming reality. In laboratories around the globe, research is being undertaken to restore function to the physically disabled, to replace areas of the brain damaged by disease or trauma and to augment human abilities. Realization of these goals relies on a diverse array of disciplines such as neuroscience, engineering, medicine and microfabrication just to name a few. This book presents a short history of neural interfacing (N.I.) research and introduces the reader to some of the current efforts to develop such an interface. The book is intended as an introduction for the college freshman or others wishing to learn more about the field. A resource guide is included for students along with a list of laboratories conducting N.I. research and universities with N.I. related tracks of study.

Neuropunk.Org is a not-for-profit, educational project of TC Design Group, LLC. The site is intended as a resource for students who wish to learn more about Neural Engineering and pursue training in one or more of its sub-disciplines. On the site you will find listings of Research groups, Universities, Individuals, companies and others who are contributing to the development of Neural Interfaces and the systems which use them. The site also serves as the Neural Engineering Wiki and a Meta-database of sites offering tools used in Neural Engineering research.

The site has recently undergone a complete re-design and now uses the popular MediaWiki framework for accessing its database. We are presently working on adding content to the database and volunteers are needed to help with this effort.

Abstract

The desire to expand the investigation of neurotransmitter measures in the CNS has led to rethinking the nature and design of microelectrode arrays (MEA). The transition from rodents to non-human primates (NHP) and eventually human recordings presents a host of issues and situations where recording methodologies and MEAs must be adjusted. The spatial orientation needed to adequately record from discrete brain foci in a variety of species under anesthetized and awake recording conditions creates a challenge and opportunity to optimize different microelectrode designs and methodologies. Some of the first MEAs to be specifically designed were those configured to provide recording sites spaced at precise distances for simultaneous recordings from the CA1 and CA3 hippocampal regions in the rat. Much has been learned about patency and function of probes as well as what methodology may work best in elucidating glutamatergic neurotransmission in the CNS from In vivo L-glutamate measures in freely moving mice and rats and awake NHPÕs. Glutamate oxidase-based (GluOx) MEAs have proven to be well tolerated and can routinely perform reliably for 7-10 days in vivo. Advances in the FAST16 recording system (Quanteon, L.L.C.) have allowed the accurate measurement of resting levels of glutamate in various brain regions of the mouse, rat and NHP. We are currently investigating whether modifying silicon nitride (SiNi) wafers can make them as inert as ceramic in vivo while providing a greater range of design options such as chemical etch out and surface modifications that SiNi substrates can provide. While we have focused on measurements of glutamate signaling, the present techniques are being modified to measure acetylcholine, choline, GABA and other neurotransmitters and metabolically important compounds.

Abstract

A variety of microelectrode array (MEA) geometries have been developed for in vivo electrochemical measures of neurotransmitters. Detection of these neurotransmitters relies on the MEA sites having precise coatings containing enzymes or other materials. In the past, coating the sites has been achieved using dipping or hand application using a micropipette. While these techniques worked well for homogeneous coatings or relatively large sites, decreasing site size and the need for different coatings to be applied to different sites on the same MEA have demanded a more precise methodology. Additionally, precise coating applications are required to decrease both the chemical cross talk between adjacent recording sites and diffusion times from the coating to the microelectrode. To address these issues a robotic apparatus has been constructed, which will permit protein patterns with less than a 15 um (+/- 1 um) feature size to be drawn onto a MEA. The robotic apparatus functions as a micro-plotter allowing the precise control of the placement and thickness of the applied coating(s). The present system is semi-automatic; requiring human directional guidance via a joystick for the coating application. The next generation of the micro-plotter is currently under development and will feature a CAD-CAM interface for fully automated coating of intact MEA wafers. The ongoing development of this technology will lead to large scale fabrication of affordable, reproducible MEAs for the analysis of a variety of neurochemicals.