Passive exercise of the hind limbs after complete thoracic transection of the spinal cord promotes cortical reorganization.

Physical exercise promotes neural plasticity in the brain of healthy subjects and modulates pathophysiological neural plasticity after sensorimotor loss, but the mechanisms of this action are not fully understood. After spinal cord injury, cortical reorganization can be maximized by exercising the non-affected body or the residual functions of the affected body. However, exercise per se also produces systemic changes - such as increased cardiovascular fitness, improved circulation and neuroendocrine changes - that have a great impact on brain function and plasticity. It is therefore possible that passive exercise therapies typically applied below the level of the lesion in patients with spinal cord injury could put the brain in a more plastic state and promote cortical reorganization. To directly test this hypothesis, we applied passive hindlimb bike exercise after complete thoracic transection of the spinal cord in adult rats. Using western blot analysis, we found that the level of proteins associated with plasticity - specifically ADCY1 and BDNF - increased in the somatosensory cortex of transected animals that received passive bike exercise compared to transected animals that received sham exercise. Using electrophysiological techniques, we then verified that neurons in the deafferented hindlimb cortex increased their responsiveness to tactile stimuli delivered to the forelimb in transected animals that received passive bike exercise compared to transected animals that received sham exercise. Passive exercise below the level of the lesion, therefore, promotes cortical reorganization after spinal cord injury, uncovering a brain-body interaction that does not rely on intact sensorimotor pathways connecting the exercised body parts and the brain

Economic, Neurobiological and Behavioral Perspectives on Building America's Future Workforce

A growing proportion of the U.S. workforce will have been raised in disadvantaged environments that are associated with relatively high proportions of individuals with diminished cognitive and social skills. A cross-disciplinary examination of research in economics, developmental psychology, and neurobiology reveals a striking convergence on a set of common principles that account for the potent effects of early environment on the capacity for human skill development. Central to these principles are the findings that early experiences have a uniquely powerful influence on the development of cognitive and social skills, as well as on brain architecture and neurochemistry; that both skill development and brain maturation are hierarchical processes in which higher level functions depend on, and build on, lower level functions; and that the capacity for change in the foundations of human skill development and neural circuitry is highest earlier in life and decreases over time. These findings lead to the conclusion that the most efficient strategy for strengthening the future workforce, both economically and neurobiologically, and for improving its quality of life is to invest in the environments of disadvantaged children during the early childhood years.

A Dominance Hierarchy of Auditory Spatial Cues in Barn Owls

Background: Barn owls integrate spatial information across frequency channels to localize sounds in space. Methodology/Principal Findings: We presented barn owls with synchronous sounds that contained different bands of frequencies (3–5 kHz and 7–9 kHz) from different locations in space. When the owls were confronted with the conflicting localization cues from two synchronous sounds of equal level, their orienting responses were dominated by one of the sounds: they oriented toward the location of the low frequency sound when the sources were separated in azimuth; in contrast, they oriented toward the location of the high frequency sound when the sources were separated in elevation. We identified neural correlates of this behavioral effect in the optic tectum (OT, superior colliculus in mammals), which contains a map of auditory space and is involved in generating orienting movements to sounds. We found that low frequency cues dominate the representation of sound azimuth in the OT space map, whereas high frequency cues dominate the representation of sound elevation. Conclusions/Significance: We argue that the dominance hierarchy of localization cues reflects several factors: 1) the relative amplitude of the sound providing the cue, 2) the resolution with which the auditory system measures the value of a cue, and 3) the spatial ambiguity in interpreting the cue. These same factors may contribute to the relative weighting of soun

Juvenile Penaeid Shrimp Ecology in a Louisiana Coastal Marsh Management Area.

Juvenile penaeid shrimp were studied by a variety of methods in a southwest Louisiana, brackish marsh. Most of the work was conducted in two study ponds, one with a fixed-crest weir and the other without. In mark and recapture studies, both brown shrimp Penaeus aztecus and white shrimp P. setiferus were found to grow faster in marsh behind a fixed-crest weir. There was no apparent weir effect on mortality of either species. Brown shrimp emigrated an average of 12 d later from marsh behind the weir; white shrimp were sometimes delayed by the weir. The peak of brown shrimp emigration from both weired and unweired marsh peaked coincided with both new and full moons. I used four methods of estimating juvenile shrimp standing stocks and found that shrimp were usually less abundant in the weired than the unweired pond. The reduction in observed emigration of shrimp from a weired area was likely caused by restricted immigration past the weir. I used density estimates from the unweired study pond and a nearby marsh pond to confirm that export estimates in previous studies of the unweired pond were reasonable, although conservative, estimates of normal numbers of shrimp emigrating from similar marsh ponds. Graphic analysis, linear statistics, and superposed epoch analysis were used to study effects of environmental variables on white shrimp emigration. White shrimp emigration from the marsh was associated with decreasing temperatures, high water outflow, decreasing and/or low barometric pressure, and rainfall

Broad Skill Focused Job Seeking: A Study of Intervention and Employment Outcomes

The job search has been the subject of research across many disciplines adopting varied perspectives. However, the industrial-organizational psychology literature on the job search has failed to properly consider the role of individual differences in thought about the utility of job skills independent of context. This dissertation is an attempt to establish and study the construct of broad skill focus- the extent to which individuals adopt a perspective and understanding of the broader generalizability of their work skills, versus their context-specific applications (i.e., the settings in which they were learned). As no measurement tool exists for studying this construct, Study 1 details the effort to develop and validate a psychometrically-sound instrument for measuring broad skill focus in individuals. It was subsequently posited that a high level of broad skill focus was advantageous for job seeking. Therefore, Study 2 served as an evaluation of an online author-developed training program (the Broad Skills Awareness Training or BSAT) designed to promote broad skill focus and employment expectancy in individuals. Results of Study 2 suggested the BSAT did exhibit merit for meaningfully increasing levels of both outcomes. Finally, Study 3 was designed to monitor the three-month employment outcomes of actual unemployed workers who have (and have not) completed the BSAT training. Final Study 3 results were mixed, again demonstrating the potential promise of the BSAT for improving broad skill focus, but not resulting in statistically significant changes in employment expectancy, and no definitive link to actual improved employment outcomes. Practical implications and future opportunities to expand this research are discussed