Spatial Probability Aids Visual Stimulus Discrimination

We investigated whether the statistical predictability of a target's location would influence how quickly and accurately it was classified. Recent results have suggested that spatial probability can be a cue for the allocation of attention in visual search. One explanation for probability cuing is spatial repetition priming. In our two experiments we used probability distributions that were continuous across the display rather than relying on a few arbitrary screen locations. This produced fewer spatial repeats and allowed us to dissociate the effect of a high-probability location from that of short-term spatial repetition. The task required participants to quickly judge the color of a single dot presented on a computer screen. In Experiment 1, targets were more probable in an off-center hotspot of high-probability that gradually declined to a background rate. Targets garnered faster responses if they were near earlier target locations (priming) and if they were near the high-probability hotspot (probability cuing). In Experiment 2, target locations were chosen on three concentric circles around fixation. One circle contained 80% of targets. The value of this ring distribution is that it allowed for a spatially restricted high-probability zone in which sequentially repeated trials were not likely to be physically close. Participant performance was sensitive to the high-probability circle in addition to the expected effects of eccentricity and the distance to recent targets. These two experiments suggest that inhomogeneities in spatial probability can be learned and used by participants on-line and without prompting as an aid for visual stimulus discrimination and that spatial repetition priming is not a sufficient explanation for this effect. Future models of attention should consider explicitly incorporating the probabilities of targets locations and features

Neighborhood Support and Children's Connectedness

Summarizes research on the links between levels of neighborhood support, such as neighbors helping one another, and other types of "connectedness" that contribute to children's healthy development -- with family, peers, community, and activities

There is no Such Thing as Attention

Given that the core issues of attention research have been recognized for millenia, we do not know as much about attention as we should. I argue that the reasons for this failure are (1) we create spurious dichotomies, (2) we reify attention, treating it as a cause, when it is an effect, and (3) we equate a collection of facts with a theory. In order to correct these errors, we need a new technical vocabulary that allows for attentional effects to be continuously distributed, rather than merely present or absent, and that provides a basis for quantitative behavioral predictions that map onto neural substrates. The terminology of the Bayesian decision process has already proved useful for structuring conceptual discussions in other psychological domains, such as perception and decision making under uncertainty, and it had demonstrated early success in the domain of attention. By rejecting a reified, causal conception of attention, in favor of theories that produce attentional effects as consequences, psychologists will be able to conduct more definitive experiments. Such conceptual advances will then enhance the productivity of neuroscientists by allowing them to concentrate their data collection efforts on the richest soil

Spatial and seasonal abundance of sand seatrout (Cynoscion arenarius) and silver seatrout (C. nothus) off the coast of Texas, determined with twenty years of data (1987–200

Sand seatrout (Cynoscion arenarius) and silver seatrout (C. nothus) are both found within the immediate offshore areas of the Gulf of Mexico, especially around Texas; however information is limited on how much distributional overlap really occurs between these species. In order to investigate spatial and seasonal differences between species, we analyzed twenty years of bay and offshore trawl data collected by biologists of the Coastal Fisheries Division, Texas Parks and Wildlife Department. Sand seatrout and silver seatrout were distributed differently among offshore sampling areas, and salinity and water depth appeared to correlate with their distribution. Additionally, within the northernmost sampling area of the gulf waters, water depth correlated significantly with the presence of silver seatrout, which were found at deeper depths than sand seatrout. There was also an overall significant decrease in silver seatrout abundance during the summer season, when temperatures were at their highest, and this decrease may have indicated a migration farther offshore. Sand seatrout abundance had an inverse relationship with salinity and water depth offshore. In addition, sand seatrout abundance was highest in bays with direct passes to the gulf and correlated with corresponding abundance in offshore areas. These data highlight the seasonal and spatial differences in abundance between sand and silver seatrout and relate these differences to the hydrological and geological features found along the Texas coastline

Water Quality Conditions and Restoration of Submerged Aquatic Vegetation (SAV) in the Tidal Freshwater James River 2005

In 2005, wild celery (Vallisneria americana) whole shoots, seeds and intact seed pods with seeds were transplanted into four sites in the Hopewell region of the tidal James River. The SAV transplants were sampled by the Virginia Institute of Marine Science (VIMS) for survivorship and growth at bi-weekly to monthly intervals throughout the growing season. Concurrently, water quality sampling was conducted at bi-weekly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SAV growth. Continuous underway sampling was also conducted along the James River tidal freshwater segments from the mouth of the Chickahominy River to the upstream limits of tidal water at Richmond. Objectives of the study were to: 1) expand the SAV transplanted plots within the study sites previously transplanted; 2) conduct water quality sampling using both fixed station and continuous underway Dataflow sampling; 3) evaluate the relationships between SAV transplant performance using seeds and whole plants and water quality. SAV transplant growth and survival were evident at all sites at depths of approximately 0.4 m below low water, when the plants were protected from herbivory by exclosures. Seeds obtained from wild stock and planted within the exclosures germinated and produced adult plants at each of the sites. The use of seeds of wild celery harvested from reproductive shoots collected in the Potomac River during the fall of 2004 proved successful. Seedlings sprouted within one month of planting at all transplant sites. The whole shoot transplants suffered some initial losses but survivorship was approximately 40% to 70%. Both seedlings produced from seed, and seed pod plantings, as well as transplanted whole shoots that were not protected by protective fencing were heavily grazed and did not survive throughout the summer. Water quality monitoring in the tidal James River in 2005 indicated continued adequate water quality for SAV growth. Turbidity levels, while highest in the upper JMSTF1 segment and lower JMSTF2 segment, were suitable for SAV growth to depths of 0.5 m in most areas. In part this is likely due to the availability of light at low tidal periods when shoot leaves can reach the water’s surface. Phytoplankton levels, measured as chlorophyll, were largely within surface water chlorophyll standards and water quality criteria for SAV growth in most areas. When integrated across the entire segments using continuous underway spatial sampling, average concentrations were found to generally be within criteria limits, except during the mid-summer. Phytoplankton did appear to contribute to reduced water clarity, although this proportion was much smaller than that caused by suspended sediments. Nutrient levels generally were comparable with earlier years’ monitoring results and long term increasing or decreasing trends since 1999 were not evident. Summertime chlorophyll levels in 2005 were higher than 2004, but much lower than those observed in 2001 and 2002. These differences may be related to water residence time in this tidal freshwater region of the James River, with highest concentrations generally observed during lower flow years. Higher salinities, and therefore lower flow and reduced flushing, in 2005 may have caused the slightly higher chlorophyll levels observed during the summer of 2005

The neural systems for perceptual updating

In a constantly changing environment we must adapt to both abrupt and gradual changes to incoming information. Previously, we demonstrated that a distributed network (including the anterior insula and anterior cingulate cortex) was active when participants updated their initial representations (e.g., it's a cat) in a gradually morphing picture task (e.g., now it's a rabbit; Stöttinger et al., 2015). To shed light on whether these activations reflect the proactive decisions to update or perceptual uncertainty, we introduced two additional conditions. By presenting picture morphs twice we controlled for uncertainty in perceptual decision making. Inducing an abrupt shift in a third condition allowed us to differentiate between a proactive decision in uncertainty-driven updating and a reactive decision in surprise-based updating. We replicated our earlier result, showing the robustness of the effect. In addition, we found activation in the anterior insula (bilaterally) and the mid frontal area/ACC in all three conditions, indicative of the importance of these areas in updating of all kinds. When participants were naïve as to the identity of the second object, we found higher activations in the mid-cingulate cortex and cuneus – areas typically associated with task difficulty, in addition to higher activations in the right TPJ most likely reflecting the shift to a new perspective. Activations associated with the proactive decision to update to a new interpretation were found in a network including the dorsal ACC known to be involved in exploration and the endogenous decision to switch to a new interpretation. These findings suggest a general network commonly engaged in all types of perceptual decision making supported by additional networks associated with perceptual uncertainty or updating provoked by either proactive or reactive decision making.FWF Austrian Science Fund, Eliese Richter Program (#V480-B27)Natural Sciences and Engineering Research Council (Discovery Grant #261628-07)Heart and Stroke Foundation of Ontario (#NA 6999)Canadian Institute of Health Research (#219972

Water Quality Conditions and Restoration of Submerged Aquatic Vegetation (SAV) in the Tidal Freshwater James River: 2003-2004

In 2003-2004 wild celery (Vallisneria americana) whole shoots and seeds were transplanted into four sites in the Hopewell region of the tidal James River. The SAV transplants were sampled by the Virginia Institute of Marine Science (VIMS) for survivorship and growth at bi-weekly to monthly intervals throughout the growing season. Concurrently, water quality sampling was conducted at bi-weekly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SAV growth. Objectives of the study were to: 1) expand the SAV transplanted plots within the study sites previously transplanted; 2) conduct water quality sampling using both fixed station and continuous underway Dataflow sampling; 3) evaluate techniques for assessing visual surface water algal conditions and water color characteristics; 4) evaluate the relationships between SAV transplant performance and water quality. SAV growth and survival were evident at all sites when the plants were protected from herbivory. Seeds obtained from wild stock and planted within the exclosures germinated and produced adult plants at each of the sites. The transplanted beds demonstrated limited impacts from hurricane Isabel with losses only evident at one transplant site. Water quality conditions in 2003 and 2004 were characterized by relatively low chlorophyll concentrations in comparison to 2002. River flow appeared to be inversely related to chlorophyll levels with a precipitous drop in chlorophyll evident for 2003 and 2004 (higher flow years) in comparison to 2002 (low flow year). Chlorophyll concentrations in 2003 and 2004 were well below the SAV habitat criteria (15mg/l) that have been associated with SAV growth to 1m. Proposed seasonal numeric chlorophyll limits under consideration by the Va. DEQ for the tidal freshwater James River (10 to 20 mg/l) would have been met in most areas in 2003 and 2004, but not in 2002. Turbidity levels were comparable among both high flow and low flow years. Water column nutrient concentrations did not vary greatly as river flow increased in 2003 and 2004 from lower flows in 2002. High ammonium concentrations found throughout this region in 2002 have not been evident since. Algal condition assessments conducted in 2004 showed little visual algal impairment. Several visual water color assessment techniques using the Flore-Ule color systems and Munsell color charts were also investigated. None were very suitable for quantifying algal and phytoplankton concentrations in this environment. This was partly due to the relative low phytoplankton concentrations present during most of this study period, the confounding effects of the varying ambient conditions, and partly due to the subjective nature of the assessment techniques themselves