Alien Registration- Hilchey, Emma (Old Town, Penobscot County)

https://digitalmaine.com/alien_docs/5925/thumbnail.jp

Driving forces in free visual search : An ethology

Peer reviewedPostprin

Intervening response events between identification targets do not always turn repetition benefits into repetition costs

When there is a relatively long interval between two successive stimuli that must be detected or localized, there are robust processing costs when the stimuli appear at the same location. However, when two successive visual stimuli that must be identified appear at the same location, there are robust same location costs only when the two stimuli differ in their responses; otherwise same location benefits are observed. Two separate frameworks that inhibited attentional orienting and episodic integration, respectively, have been proposed to account for these patterns. Recent findings hint at a possible reconciliation between these frameworks—requiring a response to an event in between two successive visual stimuli may unmask same stimulus and same location costs that are otherwise obscured by episodic integration benefits in identification tasks. We tested this hybrid account by integrating an intervening response event with an identification task that would otherwise generate the boundary between same location benefits and costs. Our results showed that the intervening event did not alter the boundary between location repetition benefits and costs nor did it reliably or unambiguously reverse the common stimulus-response repetition benefit. The findings delimit the usefulness of an intervening event for disrupting episodic integration, suggesting that effects from intervening response events are tenuous. The divide between attention and feature integration accounts is delineated in the context of methodological and empirical considerations

Response-mediated spatial priming despite perfectly valid target location cues and intervening response events

Attentional effects are often inferred from keypress reaction time (RT) studies when two sequentially presented stimuli, appearing at the same location, generate costs or benefits. The universality of these attentional attributions is challenged by data from perceptual discrimination tasks, which reveal that location repetition benefits and costs depend on whether a prior response repeats or switches, respectively. According to dual-stage accounts, these post-attentional effects may be abolished by making responses in between two target stimuli or by increasing target location certainty, leaving only attentional effects. Here, we test these accounts by requiring responses to stimuli in between targets and by increasing target location certainty with 100% valid location cues. Contrary to expectations, there was no discernible effect of cueing on any repetition effects, although the intervening response diminished stimulus-response repetition effects while subtly reducing location-response repetition effects. Despite this, there was little unambiguous evidence of attentional effects independent of responding. Taken together, the results further highlight the robustness of location-response repetition effects in perceptual discrimination tasks, which challenge whether there are enduring attentional effects in this paradigm

When do response-related episodic retrieval effects co-occur with inhibition of return?

At some point, spatial priming effects more faithfully reflect response selection processes than they do attentional orienting or sensory processes. Findings from the spatial cueing literature suggest that two factors may be critical: (1) the amount of identity processing that is required in order to respond correctly (feature-based response hypothesis), and (2) the amount of spatial processing that is required in order to respond correctly (space-based response hypothesis). To test the first hypothesis, we manipulated whether observers made single keypress detection or two-choice localization responses to serially presented stimuli in peripheral vision and whether stimulus identity information processing was necessary before responding. Responses were always slowest when the target location repeated, consistent with an attentional orienting bias independent of keypress responding (i.e., inhibition of return; IOR). The localization procedure revealed a subtle additional cost for changing the target location and repeating a response, consistent with a response-related episodic retrieval effect predicted by the Theory of Event Coding (TEC). Neither effect was modulated by the need to discriminate features. To test the second hypothesis, we made spatial processing indispensable to response selection by requiring a decision between a detection and localization response, depending on where the target appeared. IOR was eliminated for detection, but not localization, responses, consistent with the TEC. Collectively, the findings suggest that the amount of space-based, but not feature-based, processing that is required to determine a response is responsible for the response retrieval effects that can co-occur with IOR

Examining the Role of Attention and Sensory Stimulation in the Attentional Repulsion Effect

It has been suggested that visual attention warps space, such that stimuli appearing near its locus are perceived as farther away than they actually are. This is known as the attentional repulsion effect (ARE). Recent data challenge the role of attention as the sole factor responsible for the ARE, suggesting instead that the ARE is, at least in part, a product of low level sensory interactions between a peripheral orienting cue and the Vernier target stimulus used to measure the effect. Here, we directly test whether attentional orienting, without a cue in peripheral vision to guide attention, is sufficient for generating an ARE. In Experiment 1, attention was guided to the visual periphery by a central symbolic cue that reliably indicated the locations of to-be-identified targets in peripheral vision. On a subset of trials, we probed for an ARE with Vernier targets. Reaction time (RT) data revealed that the cue guided attention but there was no trace of an ARE. In Experiment 2, we ensured that the Vernier targets were sensitive to the ARE by using the standard spatially uninformative peripheral cue to guide attention instead of the central symbolic cue. RT data again revealed that the cue guided attention, while the Vernier targets revealed an ARE. Collectively, these data suggest that attentional orienting without peripheral sensory stimulation is not sufficient for generating an ARE

Modulation of Cell Surface Protein Free Thiols: A Potential Novel Mechanism of Action of the Sesquiterpene Lactone Parthenolide

There has been much interest in targeting intracellular redox pathways as a therapeutic approach for cancer. Given recent data to suggest that the redox status of extracellular protein thiol groups (i.e. exofacial thiols) effects cell behavior, we hypothesized that redox active anti-cancer agents would modulate exofacial protein thiols.To test this hypothesis, we used the sesquiterpene lactone parthenolide, a known anti-cancer agent. Using flow cytometry, and western blotting to label free thiols with Alexa Fluor 633 C(5) maleimide dye and N-(biotinoyl)-N-(iodoacetyl) ethylendiamine (BIAM), respectively, we show that parthenolide decreases the level of free exofacial thiols on Granta mantle lymphoma cells. In addition, we used immuno-precipitation techniques to identify the central redox regulator thioredoxin, as one of the surface protein thiol targets modified by parthenolide. To examine the functional role of parthenolide induced surface protein thiol modification, we pretreated Granta cells with cell impermeable glutathione (GSH), prior to exposure to parthenolide, and showed that GSH pretreatment; (a) inhibited the interaction of parthenolide with exofacial thiols; (b) inhibited parthenolide mediated activation of JNK and inhibition of NFkappaB, two well established mechanisms of parthenolide activity and; (c) blocked the cytotoxic activity of parthenolide. That GSH had no effect on the parthenolide induced generation of intracellular reactive oxygen species supports the fact that GSH had no effect on intracellular redox. Together these data support the likelihood that GSH inhibits the effect of parthenolide on JNK, NFkappaB and cell death through its direct inhibition of parthenolide's modulation of exofacial thiols.Based on these data, we postulate that one component of parthenolide's anti-lymphoma activity derives from its ability to modify the redox state of critical exofacial thiols. Further, we propose that cancer cell exofacial thiols may be important and novel targets for therapy

Entourage: the immune microenvironment following follicular lymphoma

In follicular lymphoma, nonmalignant immune cells are important. Follicular lymphoma depends on CD4+ cells, but CD8+ cells counteract it. We hypothesized that the presence of follicular lymphoma is associated with higher CD4+ than CD8+ cell numbers in the tumor microenvironment but not in the immune system. Using flow cytometry, pre-treatment and follow-up CD4/CD8 ratios were estimated in the bone marrow, blood and lymph nodes of untreated follicular lymphoma patients in two independent data sets (N1=121; N2=166). The ratios were analyzed for their relation with bone marrow lymphoma involvement. Bone marrows were also investigated with immunohistochemistry. In either data set, the bone marrow CD4/CD8 ratios were higher in bone marrows involved with lymphoma (P=0.043 and 0.0002, respectively). The mean CD4/CD8 ratio was 1.0 in uninvolved and 1.4 in involved bone marrows. Also higher in involved bone marrows were CD4/CD56 and CD3CD25/CD3 ratios. No blood or lymph node ratios differed between bone marrow-negative and -positive patients. Sequential samples showed increased bone marrow CD4/CD8 ratios in all cases of progression to bone marrow involvement. Immunohistochemistry showed CD4+, CD57+, programmed death-1+, forkhead box protein 3+ and CD21+ cells accumulated inside the lymphoma infiltrates, whereas CD8+, CD56+ and CD68+ cells were outside the infiltrates. This study provides evidence in vivo that the microenvironment changes upon follicular lymphoma involvement