bluuebunny/crossref_metadata_2025 huggingface dataset:
Expanded expression of Sonic Hedgehog inAstyanaxcavefish:multiple consequences on forebrain development and evolution
Authors: Menuet Arnaud , Alunni Alessandro , Joly Jean-Stéphane , Jeffery William R. , Rétaux Sylvie
Published: January 2007

Ventral midline Sonic Hedgehog (Shh) signalling is crucial for growth and patterning of the embryonic forebrain. Here, we report how enhanced Shh midline signalling affects the evolution of telencephalic and diencephalic neuronal patterning in the blind cavefish Astyanax mexicanus, a teleost fish closely related to zebrafish. A comparison between cave- and surface-dwelling forms of Astyanax shows that cavefish display larger Shh expression in all anterior midline domains throughout development. This does not affect global forebrain regional patterning, but has several important consequences on specific regions and neuronal populations. First, we show expanded Nkx2.1a expression and higher levels of cell proliferation in the cavefish basal diencephalon and hypothalamus. Second, we uncover an Nkx2.1b-Lhx6-GABA-positive migratory pathway from the subpallium to the olfactory bulb, which is increased in size in cavefish. Finally, we observe heterochrony and enlarged Lhx7 expression in the cavefish basal forebrain. These specific increases in olfactory and hypothalamic forebrain components are Shh-dependent and therefore place the telencephalic midline organisers in a crucial position to modulate forebrain evolution through developmental events, and to generate diversity in forebrain neuronal patterning.
Offending the other: Deconstructing narratives of deviance and pathology
Authors: Flowers Paul , Langdridge Darren
Published: January 2007

Narratives of homophobia and the repathologization of gay men now emerge and coalesce in often unconsidered ways. Within this paper, we present a deconstructive analysis of a recent paper published within the British Journal of Social Psychology (Crossley, 2004) and highlight how a narrative of repathology emerges through the selective appropriation of particular textual sources. By employing pathological constructions of sexual conduct between men; focusing upon singular homogenized constructions of gay men and simplistic constructions of health promotion and through a process of reconstructing HIV as a gay plague and it is possible to embroider a moral tale which constitutes a further deviant ‘othering’ of gay men. We contend that by employing (functional) discourses of ‘unconscious motivation’, together with a constellation of disclaimers, caveats and tokenistic pluralization, it becomes possible for psychologists to engage in homophobic knowledge production whilst maintaining an identity as a (dis)interested professional. Our analysis raises issues pertinent to all social psychologists engaged in ‘suspicious’ research on ‘the other’. To this end, we expand our critique by employing ideas from Ricoeur's hermeneutic phenomenology to provide more general discussion of ethical and constructive ways of engaging in textual analyses of persons outside one's own tradition.
The Effects of Signal Salience and Caffeine on Performance, Workload, and Stress in an Abbreviated Vigilance Task
Authors: Temple Jon G. , Warm Joel S. , Dember William N. , Jones Keith S. , LaGrange Constance M. , Matthews Gerald
Published: January 2007

In 2 experiments, a 12-min computerized vigilance task was demonstrated to reproduce the vigilance decrement, high workload (NASA-TLX), and stressful character (Dundee Stress State Questionnaire) of vigilance tasks lasting 30 min or more. In Experiment 1, the abbreviated task was also shown to duplicate the signal salience effect, a major finding associated with long-duration vigilance tasks. Moreover, Experiment 2 showed that performance on the abbreviated task can be enhanced by caffeine - a drug that benefits long-duration tasks. This enhancement effect was limited to performance, however, suggesting that caffeine influences factors that control signal detection but not those that control task-induced stress. The results parallel those obtained with long-duration tasks and support a resource-depletion model of the vigilance decrement. The abbreviated task might be useful in situations in which long-duration tasks are precluded (e.g., performance assessment batteries, neuropsychological testing, and brain imaging).
Is Dual-Task Performance Necessarily Impaired in Space?
Authors: Fowler Barry , Bock Otmar , Comfort Deanna
Published: January 2007

Recent single-subject experiments in space have reported impaired dual-task performance that could result from either a direct effect of microgravity on the central nervous system or from the multistressor environment. We sought to distinguish between these hypotheses using 6 astronauts in the 16-day NASA Neurolab mission, testing them at intervals with a dual task consisting of primary pursuit tracking without vision of the hand and secondary reaction time (RT). The participants were highly trained, instructed to maintain a fixed attention strategy, and restrained in the apparatus. The results showed that absolute and variable tracking error, as well as correct RT and the standard deviation of RT, were unimpaired. However, RT errors became more variable, an effect attributed to a decrease in strategic control. We conclude that the impairments observed in previous dual-task space experiments can be attributed to stressors rather than to microgravity and that performance deficits are probably not a necessary concomitant of space flight if attention is paid to task design and astronaut training.
The Effects of Task Complexity and Experience on Learning and Forgetting: A Field Study
Authors: Nembhard David A.
Published: January 2007

This paper examines the effects of task complexity and experience on parameters of individual learning and forgetting. Three attributes of task complexity and experience are addressed: the method, machine, and material employed. The task involved a high-manual-dexterity skill taken from an operating textile assembly plant; there were 2853 individual participant learning/forgetting episodes. A parametric model of individual learning and forgetting that allows the evaluation of worker response to the attributes of task complexity and experience is discussed. Results indicate that both task complexity and experience significantly affect learning and forgetting rates. Potential applications of this research include the allocation of workers to tasks based on individual learning/forgetting characteristics.
Measuring Team Knowledge
Authors: Cooke Nancy J. , Salas Eduardo , Cannon-Bowers Janis A. , Stout Renée J.
Published: January 2007

Multioperator tasks often require complex cognitive processing at the team level. Many team cognitive processes, such as situation assessment and coordination, are thought to rely on team knowledge. Team knowledge is multifaceted and comprises relatively generic knowledge in the form of team mental models and more specific team situation models. In this methodological review paper, we review recent efforts to measure team knowledge in the context of mapping specific methods onto features of targeted team knowledge. Team knowledge features include type, homogeneity versus heterogeneity, and rate of knowledge change. Measurement features include knowledge elicitation method, team metric, and aggregation method. When available, we highlight analytical conclusions or empirical data that support a connection between team knowledge and measurement method. In addition, we present empirical results concerning the relation between team knowledge and performance for each measurement method and identify research and methodological needs. Addressing issues surrounding the measurement of team knowledge is a prerequisite to understanding team cognition and its relation to team performance and to designing training programs or devices to facilitate team cognition.
Cognitive Task Analysis and Innovation of Training: The Case of Structured Troubleshooting
Authors: Schaafstal Alma , Schraagen Jan Maarten , van Berl Marcel
Published: January 2007

Troubleshooting is often a time-consuming and difficult activity. The question of how the training of novice technicians can be improved was the starting point of the research described in this article. A cognitive task analysis was carried out consisting of two preliminary observational studies on troubleshooting in naturalistic settings, combined with an interpretation of the data obtained in the context of the existing literature. On the basis of this cognitive task analysis, a new method for the training of troubleshooting was developed (structured troubleshooting), which combines a domain-independent strategy for troubleshooting with a context-dependent, multiple-level, functional decomposition of systems. This method has been systematically evaluated for its use in training. The results show that technicians trained in structured troubleshooting solve twice as many malfunctions, in less time, than those trained in the traditional way. Moreover, structured troubleshooting can be taught in less time than can traditional troubleshooting. Finally, technicians learn to troubleshoot in an explicit and uniform way. These advantages of structured troubleshooting ultimately lead to a reduction in training and troubleshooting costs.
Factors Influencing Analysis of Complex Cognitive Tasks: A Framework and Example from Industrial Process Control
Authors: Prietula Michael J. , Feltovich Paul J. , Marchak Frank
Published: January 2007

We propose that considering four categories of task factors can facilitate knowledge elicitation efforts in the analysis of complex cognitive tasks: materials, strategies, knowledge characteristics, and goals. A study was conducted to examine the effects of altering aspects of two of these task categories on problem solving behavior across skill levels: materials and goals. Two versions of an applied engineering problem were presented to expert, intermediate, and novice participants. Participants were to minimize the cost of running a steam generation facility by adjusting steam generation levels and flows. One version was cast in the form of a dynamic, computer-based simulation that provided immediate feedback on flows, costs, and constraint violations, thus incorporating key variable dynamics of the problem context. The other version was cast as a static computer-based model, with no dynamic components, cost feedback, or constraint checking. Experts performed better than the other groups across material conditions, and, when required, the presentation of the goal assisted the experts more than the other groups. The static group generated richer protocols than the dynamic group, but the dynamic group solved the problem in significantly less time. Little effect of feedback was found for intermediates, and none for novices. We conclude that demonstrating differences in performance in this task requires different materials than explicating underlying knowledge that leads to performance. We also conclude that substantial knowledge is required to exploit the information yielded by the dynamic form of the task or the explicit solution goal. This simple model can help to identify the contextual factors that influence elicitation and specification of knowledge, which is essential in the engineering of joint cognitive systems.
Special Section: Contending with Complexity: Developing and Using a Scaled World in Applied Cognitive Research
Authors: Ehret Brian D. , Gray Wayne D. , Kirschenbaum Susan S.
Published: January 2007

Scaled worlds preserve certain functional relationships of a complex task environment while paring away others. The functional relationships preserved are defined by the questions of interest to the researcher. Different scaled worlds of the same task may preserve and pare away different functional relationships. In this paper we use the example of Ned to discuss the use of scaled worlds in applied cognitive research. Ned is based on a detailed cognitive task analysis of submarine approach officers as they attempt to localize an enemy submarine hiding in deep water. For Ned we attempted to preserve the functional relationships inherent in the approach officer's information environment while paring away other aspects of his task environment. Scaled worlds attempt to maintain the realism inherent in the preserved functional relationship while being tractable for the researcher and engaging to the participant.
Warning Research: An Integrative Perspective
Authors: Rogers Wendy A. , Lamson Nina , Rousseau Gabriel K.
Published: January 2007

We developed an integrative perspective on the empirical evidence supporting the influence of particular variables on the warning process based on a broad review of the warning literature. The warning process is described in terms of the following four components: notice, encode, comprehend, and comply. Relevant variables are classified as person variables (characteristics of the individual interacting with the warning) and warning variables (characteristics of the warning itself or the context in which the warning appears). This integrative perspective yields general principles about the variables that influence the warning process and serves as a resource for warning developers and as a guide to facilitate effective analysis of warnings. We also identify aspects of the warning process that are not well understood, directions for effective methods of intervention, and a research agenda for future efforts. Actual or potential applications of this research include improving the design of warnings.
There Is More to Monitoring a Nuclear Power Plant than Meets the Eye
Authors: Mumaw Randall J. , Roth Emilie M. , Vicente Kim J. , Burns Catherine M.
Published: January 2007

A fundamental challenge in studying cognitive systems in context is how to move from the specific work setting studied to a more general understanding of distributed cognitive work and how to support it. We present a series of cognitive field studies that illustrate one response to this challenge. Our focus was on how nuclear power plant (NPP) operators monitor plant state during normal operating conditions. We studied operators at two NPPs with different control room interfaces. We identified strong consistencies with respect to factors that made monitoring difficult and the strategies that operators have developed to facilitate monitoring. We found that what makes monitoring difficult is not the need to identify subtle abnormal indications against a quiescent background, but rather the need to identify and pursue relevant findings against a noisy background. Operators devised proactive strategies to make important information more salient or reduce meaningless change, create new information, and off-load some cognitive processing onto the interface. These findings emphasize the active problem-solving nature of monitoring, and highlight the use of strategies for knowledge-driven monitoring and the proactive adaptation of the interface to support monitoring. Potential applications of this research include control room design for process control and alarm systems and user interfaces for complex systems.
The Effect of Automated Compensation for Incongruent Axes on Teleoperator Performance
Authors: Macedo Jose A. , Kaber David B. , Endsley Mica R. , Powanusorn Preecha , Myung Seonwan
Published: January 2007

Teleoperation is frequently performed with misalignments between operator or camera viewing direction and controller orientation. Examples of this occur in endoscopic surgery and in teleoperation with multiple camera views. The objective of this study was to find a method to automatically compensate for those misalignments so that human operators performing tasks under such scenarios could achieve levels of performance comparable to aligned conditions without additional training requirements. In this paper we report on a set of experiments conducted to test a method developed for that purpose. Participants were asked to track a randomly moving target on a computer display using a cursor controlled with a joystick. Performance was recorded under various visual-motor misalignments with and without automated compensation. Results indicated significant improvements in operator performance through use of automatic compensation only under certain types of misalignment. Actual or potential applications of this research include teleoperation and endoscopic surgery.
Analyzing Communication Sequences for Team Training Needs Assessment
Authors: Bowers Clint A. , Jentsch Florian , Salas Eduardo , Braun Curt C.
Published: January 2007

Several models of team performance have suggested that a clearer understanding of team process is needed to determine better training formats and reduce crew-generated errors. The present study investigated the degree to which analyzing communication sequences would contribute to the understanding of effective crew process in two simulated flight tasks. The results indicate that pattern analyses reveal additional strong differences between performance groups that would have been overlooked by simple frequency counts of communication. In each case, the sequential analysis shed additional light on the communication patterns that characterize better-performing teams. These results are discussed in terms of their implications for team performance research and team training. Potential applications of this research include training needs assessment, training design, and performance measurement after training.
Three-Dimensional Workspace for Industrial Workstations
Authors: Das Biman , Behara Devendra N.
Published: January 2007

Direct anthropometric measurements of maximum functional reach points were made for male and female populations to determine a three-dimensional (3D) workspace for industrial workstation design. The reach distances in the workspace spectrum were not constantly proportional to the arm length of a man or woman. It was shown that the conventionally determined workspace envelope could not be reached by 95% of the population but, rather, by only 73% of men and 75% of women. A new method was developed to determine the 3D workspace for any percentile for which the corresponding percentage population could actually reach and work efficiently. The percentile workspaces determined by the conventional and new methods were compared and found to be significantly different. Actual or potential applications of this research include designs of industrial workstations, equipment, tools, and products.
Exploring Sequential Data: Commentary on Bowers, Jentsch, Salas, and Braun (1998)
Authors: Sanderson Penelope M. , Benda Peter J.
Published: January 2007

In an investigation intended to determine training needs of flight crews, Bowers et al. (1998, this issue) report two studies showing that the patterning of communication is a better discriminator of good and poor crews than is the content of communication. Bowers et al. characterize their studies as intended to generate hypotheses for training needs and draw connections with Exploratory Sequential Data Analysis (ESDA). Although applauding the intentions of Bowers et al., we point out some concerns with their characterization and implementation of ESDA. Our principal concern is that the Bowers et al. exploration of the data does not convincingly lead them back to a better fundamental understanding of the original phenomena they are investigating.
Measures and Interpretations of Vigilance Performance: Evidence against the Detection Criterion
Authors: Balakrishnan J. D.
Published: January 2007

Operators′ performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure β from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.
The Persuasiveness of Synthetic Speech versus Human Speech
Authors: Stern Steven E. , Mullennix John W. , Dyson Corrie-lynn , Wilson Stephen J.
Published: January 2007

Is computer-synthesized speech as persuasive as the human voice when presenting an argument? After completing an attitude pretest, 193 participants were randomly assigned to listen to a persuasive appeal under three conditions: a high-quality synthesized speech system (DECtalk Express), a low-quality synthesized speech system (Monologue), and a tape recording of a human voice. Following the appeal, participants completed a posttest attitude survey and a series of questionnaires designed to assess perceptions of speech qualities, perceptions of the speaker, and perceptions of the message. The human voice was generally perceived more favorably than the computer-synthesized voice, and the speaker was perceived more favorably when the voice was a human voice than when it was computer synthesized. There was, however, no evidence that computerized speech, as compared with the human voice, affected persuasion or perceptions of the message. Actual or potential applications of this research include issues that should be considered when designing synthetic speech systems.
The Design of a Visual Display for the Presentation of Statistical Quality Control Information to Operators on the Plant Floor
Authors: D'Souza Melroy E. , Greenstein Joel S.
Published: January 2007

We applied human-centered design methodologies to enhance the presentation of product quality information to operators on a manufacturing plant floor. First, an initial visual display concept that integrated a pictorial representation of a product with standard graphical and tabular information about the product's quality was refined through iterative design and testing. A preliminary study was then conducted to determine the specific features of such a display (termed a pictorial control chart) from among eight candidate detail designs. Finally, a formal study was conducted to compare the performance of operators using this refined pictorial control chart design with their performance using a conventional control chart. Operators completed a quality control task in significantly less time using the pictorial control chart. There were no significant differences in the number of errors committed with the two charts. Subjective measures showed a significant preference for the pictorial control chart. Actual or potential applications of this research include the development of quality control tools that are useful to and usable by operators on the manufacturing plant floor.
Good Vibrations: Tactile Feedback in Support of Attention Allocation and Human-Automation Coordination in Event-Driven Domains
Authors: Sklar Aaron E. , Sarter Nadine B.
Published: January 2007

Observed breakdowns in human-machine communication can be explained, in part, by the nature of current automation feedback, which relies heavily on focal visual attention. Such feedback is not well suited for capturing attention in case of unexpected changes and events or for supporting the parallel processing of large amounts of data in complex domains. As suggested by multiple-resource theory, one possible solution to this problem is to distribute information across various sensory modalities. A simulator study was conducted to compare the effectiveness of visual, tactile, and redundant visual and tactile cues for indicating unexpected changes in the status of an automated cockpit system. Both tactile conditions resulted in higher detection rates for, and faster response times to, uncommanded mode transitions. Tactile feedback did not interfere with, nor was its effectiveness affected by, the performance of concurrent visual tasks. The observed improvement in task-sharing performance indicates that the introduction of tactile feedback is a promising avenue toward better supporting humanmachine communication in event-driven, information-rich domains.
Effects of Mission Rehearsal Simulation on Air-to-Ground Target Acquisition
Authors: Krebs William K. , McCarley Jason S. , Bryant Eric V.
Published: January 2007

Traditionally military aviators have prepared for air-to-ground bombing missions with maps and aerial photographs of their targets. Mission rehearsal systems augment these media by allowing pilots to view simulated ingress to their target, as seen from the cockpit perspective. In the present experiment we assessed the benefits of mission rehearsal with a task requiring observers to view recorded approaches to target objects and to detect the target objects as quickly as possible. Results indicated that premission simulations allowed observers to detect target objects at greater stand-off ranges than did study with maps and aerial photographs alone. Actual or potential applications of this research include the deployment of a mission rehearsal system to assist aviators' mission planning.
A New Class of Auditory Warning Signals for Complex Systems: Auditory Icons
Authors: Belz Steven M. , Robinson Gary S. , Casali John G.
Published: January 2007

This simulator-based study examined conventional auditory warnings (tonal, nonverbal sounds) and auditory icons (representational, nonverbal sounds), alone and in combination with a dash-mounted visual display, to present information about impending collision situations to commercial motor vehicle operators. Brake response times were measured for impending front-to-rear collision scenarios under 6 display configurations, 2 vehicle speeds, and 2 levels of headway. Accident occurrence was measured for impending side collision scenarios under 2 vehicle speeds, 2 levels of visual workload, 2 auditory displays, absence/presence of mirrors, and absence/presence of a dash-mounted iconic visual display. For both front-to-rear and side collision scenarios, auditory icons elicited significantly improved driver performance over conventional auditory warnings. Driver performance improved when collision warning information was presented through multiple modalities. Brake response times were significantly faster for impending front-to-rear collision scenarios using the longer headway condition. The presence of mirrors significantly reduced the number of accidents for impending side collision scenarios. Subjective preference data indicated that participants preferred multimodal displays over single-modality displays. Actual or potential applications for this research include auditory displays and warnings, information presentation, and the development of alternative user interfaces.
Foot Flare and Foot Axis
Authors: Goonetilleke Ravindra S. , Luximon Ameersing
Published: January 2007

Most commercial footwear is designed and manufactured on a curved last, although the amount of curvature of the last and the turning point of the last centerline have not been formally determined. In this study, we used principal component analysis to determine the foot axis so that lasts that match feet can be produced, resulting in a good fit. In evaluating 50 Hong Kong Chinese participants, we found that the center of the foot is located at approximately 52% of the foot length measuring from the back of the foot (SD = 0.65%) and that Hong Kong participants have a mean inflare (inward curvature) of 3.2°. The foot center and inflare measures will help determine the fit between footwear and feet. Applications of this research include the ability to incorporate foot flare into the design and manufacture of footwear.
Wrist and Forearm Posture from Typing on Split and Vertically Inclined Computer Keyboards
Authors: Marklin Richard W. , Simoneau Guy G. , Monroe John F.
Published: January 2007

A study was conducted on 90 experienced office workers to determine how commercially available alternative computer keyboards affected wrist and forearm posture. The alternative keyboards tested had the QWERTY layout of keys and were of three designs: split fixed angle, split adjustable angle, and vertically inclined (tilted or tented). When set up correctly, commercially available split keyboards reduced mean ulnar deviation of the right and left wrists from 12° to within 5° of a neutral position compared with a conventional keyboard. The finding that split keyboards place the wrist closer to a neutral posture in the radial/ulnar plane substantially reduces one occupational risk factor of workrelated musculoskeletal disorders (WMSDs): ulnar deviation of the wrist. Applications of this research include commercially available computer keyboard designs that typists can use and ergonomists can recommend to their clients in order to minimize wrist ulnar deviation from typing.
Aurally Aided Visual Search in Three-Dimensional Space
Authors: Bolia Robert S. , D'Angelo William R. , McKinley Richard L.
Published: January 2007

We conducted an experiment to evaluate the effectiveness of spatial audio displays on target acquisition performance. Participants performed a visual search task with and without the aid of a spatial audio display. Potential target locations ranged between plus and minus 180° in azimuth and from -70° to +90° in elevation. Independent variables included the number of visual distractors present (1, 5, 10, 25, 50) and the spatial audio condition (no spatial audio, free-field spatial audio, virtual spatial audio). Results indicated that both free-field and virtual audio cues engendered a significant decrease in search times. Potential applications of this research include the design of spatial audio displays for aircraft cockpits and ground combat vehicles.
Benefits of Color Coding Weapons Symbology for an Airborne Helmet-Mounted Display
Authors: Post David L. , Geiselman Eric E. , Goodyear Charles D.
Published: January 2007

We assessed the advantages of a color-coded weapons symbology for a helmetmounted display over monochrome symbology by measuring military pilots' performance while they flew air-to-air combat in a simulator. The pilots fired missiles significantly sooner without sacrificing probability of kill when using the color coded symbology, demonstrating a substantial practical benefit of color. Actual or potential applications of this work include the design of color codes for helmetmounted and other displays that use complex symbology to assist performance on cognitively challenging tasks.
Screening as an Approach for Adolescent Suicide Prevention
Authors: Peñta Juan B. , Caine Eric D.
Published: January 2007

Among the provisions of the recently signed Garrett Lee Smith Memorial Act, Congress called for the use of screening to detect adolescents who are at risk for suicide. After a review of the literature, 17 studies involving screening instruments and programs were identified. We addressed the question: What do we know about the demonstrated effectiveness and safety of screening as a tool or program to prevent suicide among adolescents? While youth suicide screening programs offer the promise of improving identification for those who need treatment the most, further research is essential to understand how, when, where, and for whom screening programs can be used effectively and efficiently.
Adolescent Suicide Attempters: What Predicts Future Suicidal Acts?
Authors: Groholt Berit , Ekeberg Øivind , Haldorsen Tor
Published: January 2007

Predictors for repetition of suicide attempts were evaluated among 92 adolescent suicide attempters 9 years after an index suicide attempt (90% females). Five were dead, two by suicide. Thirty‐one (42%) of 73 had repeated a suicide attempt. In multiple Cox regression analysis, four factors had an independent predictive effect: comorbid disorders, hopelessness, having ever received treatment for mental or behavior problems, and having a father exerting control without affection. Prediction on an individual level was difficult. Since almost half repeated a suicidal act, the best strategy is to evaluate all adolescent suicide attempters thoroughly and provide treatment as needed.
Suicide Attempts as Social Goal‐Directed Systems of Joint Careers, Projects, and Actions
Authors: Valach Ladislav , Michel Konrad , Young R. A. , Dey P.
Published: January 2007

In the present study we examined to what extent persons who attempt suicide describe their attempt in terms of social, joint processes. Psychotherapists interviewed 40 patients hospitalized in a general hospital for a few days after an attempted suicide. The content of the interviews was analyzed for the level of systemic processes the patients referred to (that is, action, project, and career). The most common processes to which the patients referred were relationship careers and projects and conflicts and argumentative actions. Our analysis indicates that a social process can be found at all levels of the patient's organization of the suicide attempt, within a system of goal‐directed action, project, and career.
Dispositional and Explanatory Style Optimism as Potential Moderators of the Relationship Between Hopelessness and Suicidal Ideation
Authors: Hirsch Jameson K. , Conner Kenneth R.
Published: January 2007

To test the hypothesis that higher levels of optimism reduce the association between hopelessness and suicidal ideation, 284 college students completed self‐report measures of optimism and Beck scales for hopelessness, suicidal ideation, and depression. A statistically significant interaction between hopelessness and one measure of optimism was obtained, consistent with the hypothesis that optimism moderates the relationship between hopelessness and suicidal ideation. Hopelessness is not inevitably associated with suicidal ideation. Optimism may be an important moderator of the association. The development of treatments to enhance optimism may complement standard treatments to reduce suicidality that target depression and hopelessness.
Nonfatal Suicide‐Related Behavior Among Inmates: Testing for Gender and Type Differences
Authors: Daigle Marc S. , Côté Gilles
Published: January 2007

Suicide‐related behavior (SRB) is significantly more prevalent among female (40.8%) than among male (28%) inmates, although suicide risk is higher among the latter. When instrumental behavior (IB) is excluded and only suicidal acts (SA) considered, rates for the two groups are more comparable (11.9% and 16%, respectively). Compared with other female inmates, the SRB group is more suicidal, hostile, and impulsive and more likely to have been previously victimized and to be diagnosed with Axis I and II disorders. Women with IB are not significantly different from those with SA, except that their behavior provides significantly greater tension release.
Reduced Anxiety, Conditioned Fear, and Hippocampal Long-Term Potentiation in Transient Receptor Potential Vanilloid Type 1 Receptor-Deficient Mice
Authors: Marsch Rudolph , Foeller Elisabeth , Rammes Gerhard , Bunck Mirjam , Kössl Manfred , Holsboer Florian , Zieglgänsberger Walter , Landgraf Rainer , Lutz Beat , Wotjak Carsten T.
Published: January 2007

The transient receptor potential vanilloid type 1 channel (TRPV1) (formerly called vanilloid receptor VR1) is known for its key role of functions in sensory nerves such as perception of inflammatory and thermal pain. Much less is known about the physiological significance of the TRPV1 expression in the brain. Here we demonstrate that TRPV1 knock-out mice (TRPV1-KO) show less anxiety-related behavior in the light–dark test and in the elevated plus maze than their wild-type littermates with no differences in locomotion. Furthermore, TRPV1-KO mice showed less freezing to a tone after auditory fear conditioning and stress sensitization. This reduction of conditioned and sensitized fear could not be explained by alterations in nociception. Also, tone perception per se was unaffected, as revealed by determination of auditory thresholds through auditory brainstem responses and distortion-product otoacoustic emissions. TRPV1-KO showed also less contextual fear if assessed 1 d or 1 month after strong conditioning protocols. These impairments in hippocampus-dependent learning were mirrored by a decrease in long-term potentiation in the Schaffer collateral–commissural pathway to CA1 hippocampal neurons. Our data provide first evidence for fear-promoting effects of TRPV1 with respect to both innate and conditioned fear and for a decisive role of this receptor in synaptic plasticity.
Cell Type-Specific Expression of a Genetically Encoded Calcium Indicator Reveals Intrinsic Calcium Oscillations in Adult Gonadotropin-Releasing Hormone Neurons
Authors: Jasoni Christine L. , Todman Martin G. , Strumia Max M. , Herbison Allan E.
Published: January 2007

The gonadotropin-releasing hormone (GnRH) neurons exhibit a unique pattern of episodic activity to control fertility in all mammals. To enable the measurement of intracellular calcium concentration ([Ca2+]i) in adult GnRH neuronsin situ, we generated transgenic mice in which the genetically encodable calcium indicator ratiometric Pericam was expressed by ∼95% of GnRH neurons. Real-time monitoring of [Ca2+]iwithin adult male GnRH neurons in the acute brain slice revealed that ∼70% of GnRH neurons exhibited spontaneous, 10–15 s duration [Ca2+]itransients with a mean frequency of 7 per hour. The remaining 30% of GnRH neurons did not exhibit calcium transients nor did a population of non-GnRH cells located within the lateral septum that express Pericam. Pharmacological studies using antagonists to the inositol-1,4,5-trisphosphate receptor (InsP3R) and several calcium channels, demonstrated that [Ca2+]itransients in GnRH neurons were generated by an InsP3R-dependent store-release mechanism and were independent of plasma membrane ligand- or voltage-gated calcium channels. Interestingly, the abolition of action potential-mediated transmission with tetrodotoxin reduced the number of [Ca2+]itransients in GnRH neurons by 50% (p< 0.05), suggesting a modulatory role for synaptic inputs on [Ca2+]itransient frequency. Using a novel transgenic strategy that enables [Ca2+]ito be examined in a specific neuronal phenotypein situ, we provide evidence for spontaneous [Ca2+]ifluctuations in adult GnRH neurons. This represents the initial description of spontaneous [Ca2+]itransients in mature neurons and shows that they arise from an InsP3R-generating mechanism that is further modulated by synaptic inputs.
Temporal Resolution for the Perception of Features and Conjunctions
Authors: Bodelón Clara , Fallah Mazyar , Reynolds John H.
Published: January 2007

The visual system decomposes stimuli into their constituent features, represented by neurons with different feature selectivities. How the signals carried by these feature-selective neurons are integrated into coherent object representations is unknown. To constrain the set of possible integrative mechanisms, we quantified the temporal resolution of perception for color, orientation, and conjunctions of these two features. We find that temporal resolution is measurably higher for each feature than for their conjunction, indicating that time is required to integrate features into a perceptual whole. This finding places temporal limits on the mechanisms that could mediate this form of perceptual integration.
Endoplasmic Reticulum Stress Inhibition Protects against Excitotoxic Neuronal Injury in the Rat Brain
Authors: Sokka Anna-Leena , Putkonen Noora , Mudo Giuseppa , Pryazhnikov Evgeny , Reijonen Sami , Khiroug Leonard , Belluardo Natale , Lindholm Dan , Korhonen Laura
Published: January 2007

Elevated brain glutamate with activation of neuronal glutamate receptors accompanies neurological disorders, such as epilepsy and brain trauma. However, the mechanisms by which excitotoxicity triggers neuronal injury are not fully understood. We have studied the glutamate receptor agonist kainic acid (KA) inducing seizures and excitotoxic cell death. KA caused the disintegration of the endoplasmic reticulum (ER) membrane in hippocampal neurons and ER stress with the activation of the ER proteins Bip, Chop, and caspase-12. Salubrinal, inhibiting eIF2α (eukaryotic translation initiation factor 2 subunit α) dephosphorylation, significantly reduced KA-induced ER stress and neuronal deathin vivoandin vitro. KA-induced rise in intracellular calcium was not affected by Salubrinal. The results show that ER responses are essential parts of excitotoxicity mediated by glutamate receptor activation and that Salubrinal decreases neuronal deathin vivo. Inhibition of ER stress by small molecular compounds may be beneficial for treatment of various neuronal injuries and brain disorders.
Caenorhabditis elegansIntegrates the Signals of Butanone and Food to Enhance Chemotaxis to Butanone
Authors: Torayama Ichiro , Ishihara Takeshi , Katsura Isao
Published: January 2007

Behavioral plasticity induced by the integration of two sensory signals, such as associative learning, is an important issue in neuroscience, but its evolutionary origin and diversity have not been explored sufficiently. We report here a new type of such behavioral plasticity, which we call butanone enhancement, inCaenorhabditis elegansadult hermaphrodites:C. elegansspecifically enhances chemotaxis to butanone by preexposure to butanone and food. Mutant analysis revealed that this plasticity requires the AWCONolfactory neuron, whose fate is known to be determined by the NSY-1/ASK1 MAPKKK (mitogen-activated protein kinase kinase kinase) cascade as well as the DAF-11 and ODR-1 guanylyl cyclases. These proteins also control many aspects of olfactory sensation/plasticity in AWC neurons and seem to provide appropriate cellular conditions for butanone enhancement in the AWCONneuron. Butanone enhancement also required the functions of Bardet-Biedl syndrome genes in the AWCONneuron but not other genes that control ciliary transport. Furthermore, preexposure to butanone and the odor of food was enough for the enhancement of butanone chemotaxis. These results suggest that the AWCONolfactory neuron may conduct a behavioral plasticity resembling associative learning and that the functions of Bardet-Biedl syndrome genes in sensory cilia may play an important role in this plasticity.
Disturbed Cross Talk between Insulin-Like Growth Factor I and AMP-Activated Protein Kinase as a Possible Cause of Vascular Dysfunction in the Amyloid Precursor Protein/Presenilin 2 Mouse Model of Alzheimer's Disease
Authors: Lopez-Lopez Cristina , Dietrich Marcelo O. , Metzger Friedrich , Loetscher Hansruedi , Torres-Aleman Ignacio
Published: January 2007

Cerebrovascular dysfunction appears to be involved in Alzheimer's disease (AD). In double mutant amyloid precursor protein/presenilin 2 (APP/PS2) mice, a transgenic model of AD, vessel homeostasis is disturbed. These mice have elevated levels of vascular endothelial growth factor (VEGF) and increased brain endothelial cell division but abnormally low brain vessel density. Examination of the potential involvement of insulin-like growth factor I (IGF-I) in these alterations revealed that treatment with IGF-I, a potent vessel growth promoter in the brain that ameliorates cognitive dysfunction in APP/PS2 mice, counteracted vascular dysfunction as follows: VEGF levels and endothelial cell proliferation were reduced, whereas vascular density was normalized. Notably, abnormally elevated brain IGF-I receptor levels in APP/PS2 mice were also normalized by IGF-I treatment. Analysis of possible processes involved in these alterations indicated that AMP-activated protein kinase (AMPK), a cell energy sensor that intervenes in angiogenic signaling and interacts with IGF-I, was also abnormally activated in APP/PS2 brains. Examination of the consequences of AMPK activation on cultured brain endothelial cells revealed increased VEGF levels together with enhanced endothelial cell proliferation and metabolism. Although these effects were also independently elicited by IGF-I, when both IGF-I and AMPK pathways were simultaneously activated on brain endothelial cells, VEGF production and endothelial cell proliferation ceased while cells remained metabolically activated (glucose use, peroxide production, and mitochondrial activity were elevated) and became more resistant to oxidative stress. Therefore, high IGF-I receptor and phosphoAMPK levels in APP/PS2 brains may reflect imbalanced IGF-I and AMPK angiogenic cross talk that could underlie vascular dysfunction in this model of AD.
Irrational Economic Decision-Making after Ventromedial Prefrontal Damage: Evidence from the Ultimatum Game
Authors: Koenigs Michael , Tranel Daniel
Published: January 2007

Emotion regulation is often critical for adaptive decision making. Here, we investigate whether emotion regulation defects following focal prefrontal brain damage are associated with exceptionally irrational economic decision making in situations of unfair treatment. In the Ultimatum Game, two players are given one opportunity to split a sum of money. One player (the proposer) offers a portion of the money to the second player (the responder) and keeps the rest. The responder can either accept the offer (in which case both players split the money as proposed) or reject the offer (in which case both players get nothing). Relatively low Ultimatum offers are often rejected, and this “irrational” behavior has been attributed to an emotional reaction to unfair treatment. Using the lesion method, we tested the hypothesis that damage to ventromedial prefrontal cortex (VMPC), an area critical for the modulation of emotional reactions, would result in exaggerated irrational economic decisions. Subjects acted as the responder to 22 different proposers who offered various splits of $10. Offers ranged from fair (give $5, keep $5) to extremely unfair (give $1, keep $9). The rejection rate of the VMPC group was higher than the rejection rates of the comparison groups for each of the most unfair offers ($7/$3, $8/$2, $9/$1). These results suggest that emotion regulation processes subserved by VMPC are a critical component of normal economic decision making.