Kenneth Short

A stress-induced anxious state in male rats: Corticotropin-releasing hormone induces persistent changes in associative learning and startle reactivity

BACKGROUND Exposure to intense inescapable stressors induces a persistent anxious state in rats. The anxious state is evident as increased sensory reactivity and enhanced associative learning. METHODS We examine whether similar neurobehavioral changes are observed after intracerebroventricular (ICV) administration of corticotropin releasing hormone (CRH). Two behaviors were observed: acoustic startle responses (ASRs) and acquisition of the classically conditioned eyeblink response. Male Sprague-Dawley rats were administered ICV CRH either in a single dose (1.0 microg/rat) or in three doses each separated by 30 min. RESULTS Exaggerated ASRs were evident 2 hours after either CRH treatment; however, only the rats given three injections exhibited a persistently exaggerated ASR apparent 24 hours after CRH treatment. Rats administered three injections of CRH also exhibited faster acquisition of the eyeblink conditioned response beginning 24 hours after treatment. Yet, we did not find evidence for a persistent activation of the HPA-axis response; three CRH injections did not lead to elevated basal plasma corticosterone levels the following morning. CONCLUSIONS Repeated treatment with CRH over a 1.5-hour period models some of the behavioral changes observed after exposure to intense inescapable stressors.

Suppression: sound and light interference with targeting

Civilian law enforcement and military operations on urban terrain (MOUT) regularly enter into unknown situations where some unidentified subset of the populace may possess armaments that may be used against them. Ultimately, the most relevant test of the effectiveness of non-lethal energies in these situations is their ability to interfere with the targeting of those weapons on the friendly forces. It is also the test that offers the most immediate and tangible reward in the prevention of personnel injuries. Perceptual interference (e.g., light-induced flash blindness) or distractions from loud noises may contribute to targeting interference. How much do various energies or perceptual interventions actually interfere with targeting? We have devised a program of experimentation that allows for the pure and precise measurement of interference with the targeting process by any of a broad range of energies and stimuli. Our primary focus has been on sound and light interference with targeting, and experiments toward that purpose are described here. As expected, targeting accuracy decreased and targeting latency increased as the distance from fixation point to the target increased. The light flash interfered more with shots at more distant targets. Furthermore, as the angle between the fixation point and the flash increased, targeting latency increased but targeting accuracy was unaffected. Thus, light interference is greatest when the flash is not at the point of fixation. These studies suggest that foveal flashes are less disruptive than peripheral flashes, and that disruption increases as targeting task demands increase.

Blunt impact as deterrent: human approach-avoidance behaviors and other stress responses studied within a paintball gaming context

Blunt impact munitions are often used by civilian law enforcement and in military operations on urban terrain (MOUT) missions to dissuade individuals and groups from approaching valued assets. The use of blunt munitions (rubber-ball or sponge) is predicated on their effectiveness as aversive stimuli; the effectiveness is weighed against the risk of serious injury or death. However, little empirical evidence supports effectiveness. Here, we use a paintball gaming context to study the effects of blunt impact on performance and approach behaviors. Volunteers individually traversed a course in which targets offer the opportunity to gain for accuracy. While completing the targeting task, subjects were bombarded with paintballs, which progressively became more numerous and the impact more intense as the subjects neared goal locations. Initial data suggest that over 30 blunt impacts by paintballs delivered at 280 ft/sec over 30 to 100 ft are insufficient to overcome intrinsic and extrinsic approach motivations or impair targeting or advance performance in an overwhelming majority of subjects. Our apparent ceiling effect was surprising. A sub-comparison of the few subjects who stopped the game before the end with those who did not suggests that personality factors influence the effectiveness of blunt impact as a deterrent. While paintballs differ from traditional blunt impact munitions on a number of physical characteristics, impact that was sufficient to repeatedly bruise volunteers was not an effective deterrent.

360/spl deg/ sound and light interference targeting system

Sound and light stimuli elicit a considerable portion of human sensory activity and are utilized in psychophysics and neurology research. The engineering objective was to develop an automated system able to determine how sound and light interference affect the accuracy of the human targeting system in a three-dimensional space. This was achieved by development of a hardware and software system, sound and light interference targeting or SLIT, which presented the subject with a sound or light target, preceded by a sound or light interference. Sony/spl copy/ Xpl5d 4-way speakers presented sound interference and sound targeting. The Martin/spl reg/ MiniMAC Profile operated as a source of light interference, while a red laser served as a light target. Data were collected via the Ascension Flock of Birds tracking system and a custom National Instruments/spl reg/ LabVIEW/sup /spl trade// 7.0 program. The developed SLIT system enables the tracking of virtual shots from a fired simulation gun in 360 degrees of direction within a cylindrical environment.

Virtual targeting in three-dimensional space

Methods of measuring human gun shot accuracy include tracing real or virtual shots. Issues in utilizing real shots in shot accuracy experiments involve intermittently halting the study to restore the integrity of the apparatus and reduced safety due to fired projectiles. A videogame is an existing form of a virtual targeting system employing a light gun. However, this device limits users to two dimensions. A tracking system was developed to monitor gun movement and firing in three-dimensional space. Two test protocols examined the reliability of the system. The first tested the repeatability of the system while the second verified the accuracy of the system. For 25 targets, with n=9 for each target, the first test revealed average distances missed for x, y and z of 0.08 inches, 0.05 inches and 0.05 inches respectively. The second test determined a system error rate of 0.1 inches. The system provides the ability to determine shot accuracy and location, given specific targets.

Developing psychophysiological profiles for monitoring stress

Training prepares first responders for disasters including terrorist attacks. To train effectively it should be as realistic as possible and elicit the stress response. We are developing a profile that will be a marker for intensity of stress as well as differentiate stress from exertion. We have monitored stress during several training scenarios for different groups including civilian SWAT teams and the military. In addition, we can monitor stress to exposure to nonlethal weapons. We have monitored stress during exposure to blunt impact using a paintball paradigm. We have measured salivary substances (such as cortisol and DHEA [markers for the hypothalamic-pituitary-adrenal axis]) and amylase [marker for the sympathetic branch of the autonomic nervous system], physiological parameters (such as activity and heart rate), and neuropsychological assessment tools (such as Borgs perceived exertion scale, Spielbergers STAI and Thayers ADC). With these neuroendocrine, physiological and behavioral indices in hand, we are poised to examine stress induction in preparedness in trainees.

Suppression through acoustics

This paper reviews research conducted by our laboratory exploring the possible use of acoustical stimuli as a tool for influencing behavior. Over the course of several programs, different types of acoustic stimuli have been evaluated for their effectiveness in disrupting targeting, balance, and high-order cognitive processes in both humans and animals. Escape responses are of particular use in this regard. An escape response serves not only as an objective measure of aversion, but as a potential substitute for ongoing behavior. We have also assessed whether the level of performance changes if the individual does not perform an escape response. In general these studies have both suggested certain types of sounds are more aversive or distracting than others. Although the laboratory development of additional stimuli needs to continue, we are taking the next step by testing some of the more effective stimuli in more applied experimental scenarios including those involving group dynamics.

Synthetic fog as a non-lethal obscurant

Obscurants containing glycols and glycerin, which are widely used in the entertainment industry to produce theatrical effects, are now being used in more concentrated forms in antitheft and riot control. While there have been several studies demonstrating that theatrical fogs are innocuous for humans, the toxicity of the denser fogs has not been examined. In this paper we review the results of previous safety studies of theatrical fog, summarize the effect of increasing concentrations of these obscurants on visibility, and then report on the physiological and biochemical impact of higher concentrations of these obscurants for several hours in rats. Our results suggest that even prolonged exposure to highly obscurant levels of propylene glycol / glycerin fog produces only minimal physiological aftereffects.

Virtual targeting in three-dimensional space with sound and light interference

Law enforcement and the military are critically concerned with the targeting and firing accuracy of opponents. Stimuli which impede opponent targeting and firing accuracy can be incorporated into defense systems. An automated virtual firing range was developed to assess human targeting accuracy under conditions of sound and light interference, while avoiding dangers associated with live fire. This system has the ability to quantify sound and light interference effects on targeting and firing accuracy in three dimensions. This was achieved by development of a hardware and software system that presents the subject with a sound or light target, preceded by a sound or light interference. Sony© Xplod.TM 4-way speakers present sound interference and sound targeting. The Martin ® MiniMACTM Profile operates as a source of light interference, while a red laser light serves as a target. A tracking system was created to monitor toy gun movement and firing in three-dimensional space. Data are collected via the Ascension ® Flock of BirdsTM tracking system and a custom National Instrument ® LabVIEWTM 7.0 program to monitor gun movement and firing. A test protocol examined system parameters. Results confirm that the system enables tracking of virtual shots from a fired simulation gun to determine shot accuracy and location in three dimensions.