Center for Visual Communication (United States)

Oscillatory activity is a hallmark of neural function across spatial and temporal scales, but its origins and computational roles remain only partially understood. Since our earlier caution against treating alpha-band activity as a unitary phenomenon, converging work has highlighted the need to interpret brain rhythms within their anatomical and functional context. Here we provide both a comprehensive review of this progress and a perspective-style framework, the resonant hierarchy, which situates oscillations within a nested scaffold spanning from dendritic microstructure to macroscale inter-areal coordination. At the cellular level, dendritic branches act as spatially organized filters with frequency-selective resonance properties. At larger scales, conduction delays and anatomical layout constrain dominant communication frequencies, aligning structural hierarchy with temporal coordination regimes. We argue that canonical rhythms (alpha, beta, gamma, etc.) should be understood not as fixed cognitive modules, but as emergent descriptors of these coordination regimes. In contrast to previous multiscale accounts that focus primarily on laminar microcircuits or network-level eigenmodes, we explicitly link dendritic resonance, laminar organization, and long-range conduction delays into a single cross-scale framework and articulate how they jointly shape latent population dynamics. This perspective unifies diverse findings and generates testable predictions: manipulations of dendritic resonance should systematically shift network oscillations; disruptions of conduction pathways should alter inter-areal alignment; and targeted neuromodulation may work best by nudging latent dynamics along resonant dimensions. In integrating review with framework, we aim to reposition oscillations as fundamental scaffolds of computation, offering a principled basis for future modeling, measurement, and intervention.

Visual search has traditionally been conceptualized as the process by which the visual system identifies relevant objects in the extrafoveal field for subsequent foveation. Standard models implicitly assume there is no need for a finer-level search within the 1-degree foveola, as stimuli falling in this region are already viewed at high resolution. Using state-of-the-art high-precision eye tracking with arcminute level accuracy to localize the line of sight, we show that the visuomotor system is capable of implementing effective visual search strategies with striking precision within the foveated region. This active behavior, mediated by microsaccades, tiny saccades just a few arcminutes in size, allows for an efficient examination of the details falling in the central fovea. Our findings challenge the traditional visual search view and reveal that at each fixation a finer priority map of the foveal input is established, underscoring the dynamic nature of these representations.

Front Cover: The cover image is based on the Article Interaction of Phosphorylated C5aR1 With β‐Arrestin1: A Comparative Structural Modeling Study by Soumendra Rana et al., https://doi.org/10.1002/prot.70007. image

Humans explore visual scenes through frequent, rapid gaze shifts known as saccades. These movements redirect the high-acuity region of the retina toward objects of interest, thus selecting information based on location. Here, we show that saccade amplitude provides a separate and complementary form of selection, effectively filtering visual information by spatial frequency rather than location. Specifically, a reduction in saccade amplitude attenuates post-saccadic visual sensitivity in an amplitude-dependent range of low spatial frequencies. This effect is highly robust, so that even minute changes in saccade size considerably affect visibility. We show that this phenomenon arises from the way the magnitude-dependent kinematic characteristics of saccades transform the visual world into a spatiotemporal flow: post-saccadic visibility closely follows theoretical predictions based on the spatial information that saccade transients convey within the temporal bandwidth of retinal sensitivity. Thus, saccades not only guide selection based on location, but also filter visual information based on content, actively shaping perception.

Why do some cortically blind (CB) drivers who are missing a quadrant or more of their visual field have trouble maintaining a central lane position (Bowers et al. IOVS 2014), while others do not? A recent driving study in virtual reality showed that most right-sided CBs perform similarly to controls, while most left-sided CBs steer differently (Giguere et al. JoV 2024). Here, we asked whether these steering differences arise from the occlusion of visual information or from noise and/or biases in visual motion processing introduced by CB (Cavanaugh et al. JoV 2015). The steering and gaze behavior of 30 subjects with normal vision (mean age: 19.9 years, SD: 1.35) was recorded in a virtual steering task where artificial occluding “scotomas” were imposed on a quadrant of their visual field. The central five degrees of vision were spared to mimic the sparing present in most CB patients. Turn direction (left/right), turn radius (two non-constant radii), and occlusion quadrant (one of four quadrants or no occlusion) were randomized between trials. Participants were biased in lane position away from the side of the simulated blind field with one exception: lane position was unchanged when turning away from occlusions in the upper quadrants. With respect to eye movements, the occlusion quadrant did not affect average gaze azimuth/elevation, percent fixations on road, or look-ahead distance on road. However, participants made fewer saccades when turning towards an upper quadrant occlusion. This study shows that spontaneous occlusion of visual information in the upper vs lower visual field biases steering, but left vs. right occlusions do not fully account for the differences that arise from left and right-sided CB. Future work should examine the influence of CB adaptation to their visual impairments and the effect of internal processing noise on steering.

The cover image is based on the article Identification of Sinigrin as Active Compound of Rape Pollen for Treating Benign Prostatic Hyperplasia Through PI3K/AKT/mTOR Axis by Bingliang Chen et al., https://doi.org/10.1002/ptr.8447. image

The cover image is based on the article Effect of berberine on the hippocampal structure, biochemical factors, memory, and blood‐brain barrier in rat model of transient global cerebral ischemia by Dariush Mehboodi et al., https://doi.org/10.1002/ptr.8234.image

The purpose of this study was to evaluate the biomechanical and hydration differences in scleral tissue after two modalities of collagen cross-linking. Scleral tissue from 40 adult white rabbit eyes was crosslinked by application of 0.1% Rose Bengal solution followed by 80 J/cm2 green light irradiation (RGX) or by application of 0.1% riboflavin solution followed by 5.4 J/cm2 ultraviolet A irradiation (UVX). Posterior scleral strips were excised from treated and untreated sclera for tensile and hydration-tensile tests. For tensile tests, the strips were subjected to uniaxial extension after excision. For hydration-tensile tests, the strips were dehydrated, rehydrated, and then tested. Young's modulus at 8% strain and swelling rate were estimated. ANOVAs were used to test treated-induced differences in scleral biomechanical and hydration properties. Photo-crosslinked sclera tissue was stiffer (Young's modulus at 8% strain: 10.7 ± 4.5 MPa, on average across treatments) than untreated scleral tissue (7.1 ± 4.0 MPa). Scleral stiffness increased 132% after RGX and 90% after UVX compared to untreated sclera. Scleral swelling rate was reduced by 11% after RGX and by 13% after UVX. The stiffness of the treated sclera was also associated with the tissue hydration level. The lower the swelling, the higher the Young's modulus of RGX (-3.8% swelling/MPa) and UVX (-3.5% swelling/MPa) treated sclera. Cross-linking with RGX and UVX impacted the stiffness and hydration of rabbit posterior sclera. The Rose Bengal with green light irradiation may be an alternative method to determine the efficacy and suitability of inducing scleral tissue stiffening in the treatment of myopia.