Parallel Advantage: Further Evidence for Bottom-up Saliency Computation by Human Primary Visual Cortex

Finding a target among uniformly oriented non-targets is typically faster when this target is perpendicular, rather than parallel, to the non-targets. The V1 Saliency Hypothesis (V1SH), that neurons in the primary visual cortex (V1) signal saliency for exogenous attentional attraction, predicts exactly the opposite in a special case: each target or non-target comprises two equally sized disks displaced from each other by 1.2 disk diameters center-to-center along a line defining its orientation. A target has two white or two black disks. Each non-target has one white disk and one black disk, and thus, unlike the target, activates V1 neurons less when its orientation is parallel rather than perpendicular to the neurons’ preferred orientations. When the target is parallel, rather than perpendicular, to the uniformly oriented non-targets, the target’s evoked V1 response escapes V1’s iso-orientation surround suppression, making the target more salient. I present behavioral observations confirming this prediction.

Saturation effects in SIDIS at very forward rapidities

Using the dipole picture for electron-nucleus deep inelastic scattering at small Bjorken x, we study the effects of gluon saturation in the nuclear target on the cross-section for SIDIS (single inclusive hadron, or jet, production). We argue that the sensitivity of this process to gluon saturation can be enhanced by tagging on a hadron (or jet) which carries a large fraction z ≃ 1 of the longitudinal momentum of the virtual photon. This opens the possibility to study gluon saturation in relatively hard processes, where the virtuality Q2 is (much) larger than the target saturation momentum $$ {Q}_s^2 $$ Q s 2 , but such that z(1 − z)Q2 ≲ $$ {Q}_s^2 $$ Q s 2 . Working in the limit z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we predict new phenomena which would signal saturation in the SIDIS cross-section. For sufficiently low transverse momenta k⊥ ≪ Qs of the produced particle, the dominant contribution comes from elastic scattering in the black disk limit, which exposes the unintegrated quark distribution in the virtual photon. For larger momenta k⊥ ≳ Qs, inelastic collisions take the leading role. They explore gluon saturation via multiple scattering, leading to a Gaussian distribution in k⊥ centred around Qs. When z(1 − z)Q2 ≪ Q2, this results in a Cronin peak in the nuclear modification factor (the RpA ratio) at moderate values of x. With decreasing x, this peak is washed out by the high-energy evolution and replaced by nuclear suppression (RpA< 1) up to large momenta k⊥ ≫ Qs. Still for z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we also compute SIDIS cross-sections integrated over k⊥. We find that both elastic and inelastic scattering are controlled by the black disk limit, so they yield similar contributions, of zeroth order in the QCD coupling.

Attention cueing in rivalry: insights from pupillometry

We used pupillometry to evaluate the effects of attention cueing on perceptual bi-stability, as reported by adult human observers. Perceptual alternations and pupil diameter were measured during two forms of rivalry, generated by presenting a white and a black disk to the two eyes (binocular rivalry) or splitting the disks between eyes (interocular grouping rivalry). In line with previous studies, we found that subtle pupil size oscillations (about 0.05 mm) tracked alternations between exclusive dominance phases of the black or white disk. These oscillations were larger for perceptually stronger stimuli: presented to the dominant eye or with physically higher luminance contrast. However, cueing of endogenous attention to one of the rivaling percepts did not affect pupil oscillations during exclusive dominance phases. This was in spite of the reliable effects of endogenous attention on perceptual dominance, which shifted in favor of the cued percept by about 10%. The results were comparable for binocular and interocular grouping rivalry. Cueing only had a marginal modulatory effect on pupil size during mixed percepts in binocular rivalry. This may suggest that, rather than acting by modulating perceptual strength, endogenous attention primarily acts during periods of unresolved competition, which is compatible with attention being automatically directed to the rivaling stimuli during periods of exclusive dominance and thereby sustaining perceptual alternations.

Visible and invisible displacement with dynamic visual occlusion in bottlenose dolphins (Tursiops spp)

Anticipating the location of a temporarily obscured target—what Piaget (the construction of reality in the child. Basic Books, New York, 1954) called ‘‘objectpermanence’’—is a critical skill, especially in hunters of mobile prey. Previous research with bottlenose dolphins found they could predict the location of a target that had been visibly displaced into an opaque container, but not one that was first placed in an opaque container and then invisibly displaced to another container. We tested whether, by altering the task to involve occlusion rather than containment, these animals could show more advanced object permanence skills. We projected dynamic visual displays at an underwater-viewing window and videotaped the animals’ head moves while observing these displays. In Experiment 1, the animals observed a small black disk moving behind occluders that shifted in size, ultimately forming one large occluder. Nine out of ten subjects ‘‘tracked’’ the presumed movement of the disk behind this occluder on their first trial—and in a statistically significant number of subsequent trials—confirming their visible displacement abilities. In Experiment 2, we tested their invisible displacement abilities. The disk first disappeared behind a pair of moving occluders, which then moved behind a stationary occluder. The moving occluders then reappeared and separated, revealing that the disk was no longer behind them. The subjects subsequently looked to the correct stationary occluder on eight of their ten first trials, and in a statistically significant number of subsequent trials. Thus, by altering the stimuli to be more ecologically valid, we were able to show that the dolphins could indeed succeed at an invisible displacement task.

Black Culture, Music, and “Hep Phrasing” Permeated Radio

In 1947, WJBW took a bold move. It began live remotes from a black nightclub, the Dew Drop Inn. In 1949 Vernon Winslow—who would become the city's first full-time black disk jockey at WWEZ—was unsuccessful convincing WJMR's management to hire him as a DJ. The station refused to hire a black man but made Winslow a consultant who created the black trickster character Poppa Stoppa and taught white men to speak in a hip black vernacular. After firing Winslow because he went on air as Poppa Stoppa, the Jax brewery picked him up to expand its black beer drinking market. It contracted with WWEZ for which Winslow created his DJ nickname, Dr. Daddy-O, and operated his new show “Jivin’ with Jax.”

Preliminary Experience with a Novel System of Facet Fixation to Treat Patients with Lumbar Degenerative Disease. A New Perspective in Minimally Invasive Spine Surgery?

Purpose We report our experience with a novel surgical device for the treatment of lumbar degenerative microinstability. Facet Wedge (DePuy Synthes, Raynham, Massachusetts, United States) is a novel technique of intra-articular lumbar facet fixation that provides a minimally invasive alternative to standard posterior fixation. Materials and Methods From November 2014 to July 2015, 38 patients underwent single-level Facet Wedge implantation. The main surgical indications included herniated disk (18 patients), spinal canal and foraminal stenosis (14 patients), and Meyerding grade I degenerative spondylolisthesis (6 patients). All the patients showed radiologic signs of microinstability: hyperintensity in both facet joints (facet fluid signal) in T2-weighted magnetic resonance imaging and a black disk as a sign of degenerative disease. No slippage was evident at dynamic radiograph. After a period of conservative treatment (minimum of 6 months), surgery was performed. All patients' follow-up lasted over at least 12 months. Results The low back visual analog scale score decreased significantly after surgery (from an average of 8.2 to 3.1 at final follow-up). Postoperatively, the Oswestry Disability Index showed a significant reduction (14.7 on average). No slippage or signs of adjacent segment degeneration was detected in neuroimaging follow-up. Conclusion Facet Wedge allows facet fixation in lumbar degenerative microinstability. To the best of our knowledge, this is the first clinical series reported in the literature on this novel device.

Turn Your Radio On

This chapter focuses on the pioneers of sacred music radio broadcasting in Chicago. During the 1920s, several Chicago Pentecostal and Holiness church leaders discovered the potential of radio as a medium for transmitting their ministries to households throughout Chicago and beyond. It was through radio that Chicago's white community was introduced to the sounds of sanctified singing and preaching. As a cultural and economic phenomenon, black-oriented radio in Chicago traces its roots to 1929 and the entrepreneurial efforts of Jack L. Cooper, the first black disk jockey not only in Chicago but in all of the United States. In Bronzeville, Elder Lucy Smith's All Nations Pentecostal Church and Rev. Clarence H. Cobbs's First Church of Deliverance were early adopters of radio for transmitting church services. This chapter examines the radio broadcasts of the All Nations Pentecostal Church and the First Church of Deliverance that allowed gospel music to be heard throughout Chicago, the Midwest, and, ultimately, the nation.