Bioelectronic medicines: a research roadmap

Realizing the vision of a new class of medicines based on modulating the electrical signalling patterns of the peripheral nervous system needs a firm research foundation. Here, an interdisciplinary community puts forward a research roadmap for the next 5 years

Doctor of Philosophy

dissertationToday, we are implanting electrodes into many different parts of the peripheral and central nervous systems for the purpose of restoring function to people with nerve injury or disease. As technology and manufacturing continue to become more advanced, ne

Closed-loop approaches for innovative neuroprostheses

The goal of this thesis is to study new ways to interact with the nervous system in case of damage or pathology. In particular, I focused my effort towards the development of innovative, closed-loop stimulation protocols in various scenarios: in vitro, ex vivo, in vivo

Orthotic and Prosthetic Management in Brachial Plexus Injury: Recent Trends

The brachial plexus is a network of intertwined nerve that controls movement and sensation in arm and hand. Any injury to the brachial plexus can result in partial or complete damage of arm and hand. The surgery is a common indicative procedure in brachial plexus injury in case of non-spontaneous recovery. The loss of function of hand due to injury can be replaced by using body powered or externally powered devices. Recent development in treatment protocol of prosthetic and orthotic science using artificial intelligence helps in rehabilitating the persons with brachial plexus injury to regain his confidence and perform daily activities. Combination of advancement in surgical procedure along with artificially intelligent devices opens a new array to rehabilitate the person with brachial plexus injury

Technology applications

A summary of NASA Technology Utilization programs for the period of 1 December 1971 through 31 May 1972 is presented. An abbreviated description of the overall Technology Utilization Applications Program is provided as a background for the specific applications examples. Subjects discussed are in the broad headings of: (1) cancer, (2) cardiovascular disease, (2) medical instrumentation, (4) urinary system disorders, (5) rehabilitation medicine, (6) air and water pollution, (7) housing and urban construction, (8) fire safety, (9) law enforcement and criminalistics, (10) transportation, and (11) mine safety

CHARACTERIZATION AND OPTIMIZATION OF MICROELECTRODE ARRAYS FOR GLUTAMATE MEASUREMENTS IN THE RAT HIPPOCAMPUS

An overarching goal of the Gerhardt laboratory is the development of an implantable neural device that allows for long-term glutamate recordings in the hippocampus. Proper L-glutamate regulation is essential for hippocampal function, while glutamate dysregulation is implicated in many neurodegenerative diseases. Direct evidence for subregional glutamate regulation is lacking in previous in vivo studies because of limitations in the spatio-temporal resolution of conventional experimental techniques. We used novel enzyme-coated microelectrode arrays (MEAs) for rapid measurements (2Hz) of extracellular glutamate in urethane-anesthetized rats. Potassium-evoked glutamate release was highest in the cornu ammonis 1 (CA1) subregion and lowest in the cornu ammonis 3 (CA3). In the dentate gyrus (DG), evoked-glutamate release was diminished at a higher potassium concentration but demonstrated faster release kinetics. These studies are the first to show subregion specific regulation of glutamate release in the hippocampus. To allow for in vivo glutamate measurements in awake rats, we have adapted our MEAs for chronic use. Resting glutamate measurements were obtained up to six days post-implantation but recordings were unreliable at later time points. To determine the cause(s) for recording failure, a detailed investigation of MEA surface characteristics was conducted. Scanning electron microscopy and atomic force microscopy showed that PT sites have unique surface chemistry, a microwell geometry and nanometer-sized features, all of which appear to be favorable for high sensitivity recordings. Accordingly, studies were initiated to improve enzyme coatings using a computer-controlled microprinting system (Microfab Technologies, Plano, TX). Preliminary testing showed that microprinting allowed greater control over the coating process and produced MEAs that met our performance criteria. Our final studies investigated the effects of chronic MEA implantation. Immunohistochemical analysis showed that the MEA produced minimal damage in the hippocampus at all time points from 1 day to 6 months. Additionally, tissue attachment to the MEA surface was minimal. Taken together with previous electrophysiology data supporting that MEAs are functional up to six months, these studies established that our chronic MEAs technology is capable of maintaining a brain-device interface that is both functional and biocompatible for extended periods of time

The peripheral nervous system: injury and disease

Poor functional outcomes are frequent after peripheral nerve injuries despite the regenerative support of Schwann cells. Whilst motoneurons and to a lesser extent, sensory neurons survive the injuries, outgrowth of axons across the injury site is slow and the neuronal regenerative capacity is progressively reduced when neurons remain without targets and chronically denervated Schwann cells fail to support axon growth. Strategies including brief low frequency electrical stimulation that accelerates axon outgrowth and, in turn, target reinnervation and functional recovery, have excellent potential for translation to human patients. Other strategies including the insertion of cross-bridges between a donor nerve and a recipient denervated nerve stump, are effective in promoting functional outcomes after complete injuries. During muscle reinnervation the properties of the motoneurons and muscle fibers that they supply are rematched that provide some control of muscle force even when regenerating axons are misdirected to foreign targets. Axon sprouting from intact nerves is effective, although limited, in reinnervating denervated muscle fibers after incomplete injuries and in poliomyelitis. Studies in mouse models of amyotrophic lateral sclerosis however, indicate that sprouting is very limited with rapid and preferential loss of the largest and fastest contracting motor units during the asymptomatic phase of the disease

Aerospace Medicine and Biology: A cumulative index to a continuing bibliography

This publication is a cumulative index to the abstracts contained in Supplements 138 through 149 of AEROSPACE MEDICINE AND BIOLOGY: A CONTINUING BIBLIOGRAPHY. It includes three indexes -- subject, personal author, and corporate source