Aerospace Medicine and Biology: A continuing bibliography (supplement 249)

This bibliography lists 311 reports, articles and other documents introduced into the NASA scientific and technical information system in August 1983

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 258)

This bibliography lists 308 reports, articles and other documents introduced into the NASA scientific and technical information system in April 1984

Workshop on Countering Space Adaptation with Exercise: Current Issues

The proceedings represent an update to the problems associated with living and working in space and the possible impact exercise would have on helping reduce risk. The meeting provided a forum for discussions and debates on contemporary issues in exercise science and medicine as they relate to manned space flight with outside investigators. This meeting also afforded an opportunity to introduce the current status of the Exercise Countermeasures Project (ECP) science investigations and inflight hardware and software development. In addition, techniques for physiological monitoring and the development of various microgravity countermeasures were discussed

Bayesian time perception

Time is an elemental dimension of human perception, cognition and action. Innumerable studies have investigated the perception of time over the last 100 years, but the computational basis for the processing of temporal information remains unknown. This thesis aims to understand the mechanisms underlying the perceived timing of stimuli. We propose a novel Bayesian model of when stimuli are perceived that is consistent with the predictive coding framework – such a perspective to how the brain deals with temporal information forms the core of this thesis. We theorize that that the brain takes prior expectations about when a stimulus might occur in the future (prior distribution) and combines it with current sensory evidence (likelihood function) in order to generate a percept of perceived timing (posterior distribution). In Chapters 2-4, we use human psychophysics to show that the brain may bias perception such that slightly irregularly timed stimuli as reported as more regular. In Chapter 3, we show how an environment of irregularity can cause regularly timed sequences to be perceived as irregular whilst Chapter 4 shows how changes in the reliability of a signal can cause an increased attraction towards expectation

Behavioral Insights into Nociceptor Function: A Systematic Approach to Understanding Postsurgical and Neuropathic Pain Mechanisms in Rats

Postsurgical and neuropathic pain are each clinically common, and often associated with ongoing pain. Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors. Preclinical studies using rodent neuropathic models have concentrated on allodynia driven by OA generated in non-nociceptive Aβ fibers, but little attention has been paid to postsurgical pain in sham controls or to C-fiber nociceptor OA promoting ongoing pain. Operant assays that reveal negative motivational and cognitive aspects of voluntary pain-related behavior may be particularly sensitive to pain-related alterations. In the mechanical conflict (MC) test, rodents can freely choose to escape from a brightly lit chamber by crossing sharp probes. Most studies employing the MC test habituate rodents to the device and measure the latency to escape the bright light. We found reducing habituation caused rats to repeatedly return to the light chamber when probes were absent, presumably as part of their exploratory behavior. We asked whether combining motivations to avoid the bright light and to explore the device would reveal a conflicting, pain-related reluctance of rats to cross noxious probes. Rats with a thoracic spinal cord injury (SCI), lumbar spinal nerve transection, or chronic constriction injury of the sciatic nerve, as well as their sham controls, exhibited heightened pain-avoidance behavior compared to uninjured controls. These findings have important implications for investigations into behavioral and neuronal alterations contributing to postsurgical and neuropathic pain. Many C-fiber nociceptors generate OA in vivo in rats with SCI and ongoing pain. Probable nociceptors continue to generate OA in vitro after dissociation. We used whole-cell recordings from isolated dorsal root ganglion neurons and novel algorithms that analyze irregular changes in membrane potential (MP) to define neurophysiological alterations underlying SCI-induced nociceptor OA. In a distinct type of probable nociceptor, SCI caused 3 chronic alterations that promote OA: 1) depolarization of resting MP, 2) reduction in the voltage threshold for action potential generation, and 3) enhancement of depolarizing spontaneous fluctuations (DSFs) in MP. In vitro modeling of acute inflammation by combining serotonin with artificial depolarization also potentiated DSFs and OA. These findings reveal nociceptor specializations for generating OA during ongoing pain

Muscular activity and its relationship to biomechanics and human performance

The purpose of this manuscript is to address the issue of muscular activity, human motion, fitness, and exercise. Human activity is reviewed from the historical perspective as well as from the basics of muscular contraction, nervous system controls, mechanics, and biomechanical considerations. In addition, attention has been given to some of the principles involved in developing muscular adaptations through strength development. Brief descriptions and findings from a few studies are included. These experiments were conducted in order to investigate muscular adaptation to various exercise regimens. Different theories of strength development were studied and correlated to daily human movements. All measurement tools used represent state of the art exercise equipment and movement analysis. The information presented here is only a small attempt to understand the effects of exercise and conditioning on Earth with the objective of leading to greater knowledge concerning human responses during spaceflight. What makes life from nonliving objects is movement which is generated and controlled by biochemical substances. In mammals. the controlled activators are skeletal muscles and this muscular action is an integral process composed of mechanical, chemical, and neurological processes resulting in voluntary and involuntary motions. The scope of this discussion is limited to voluntary motion

Handbook on clinical neurology and neurosurgery

HANDBOOKNEUROLOGYNEUROSURGERYКЛИНИЧЕСКАЯ НЕВРОЛОГИЯНЕВРОЛОГИЯНЕЙРОХИРУРГИЯThis handbook includes main parts of clinical neurology and neurosurgery