Visual Research Articles

Volumetric alterations in auditory and visual subcortical nuclei following perinatal deafness in felines.

In response to sensory deprivation, the brain adapts to efficiently navigate a modified perceptual environment through a process referred to as compensatory crossmodal plasticity, allowing the remaining senses to repurpose deprived regions and networks. A mechanism that has been proposed to contribute to this plasticity involves adaptations within subcortical nuclei that trigger cascading effects throughout the brain. The current study uses 7T MRI to investigate the effect of perinatal deafness on the volumes of subcortical structures in felines, focusing on key sensory nuclei within the brainstem and thalamus. Using both ROI-based and morphometric approaches, the regional macrostructure of four auditory and two visual nuclei were studied, as well as the corresponding volumetric asymmetries within and across groups. In the auditory pathway, significant bilateral volumetric reductions were revealed within the lower-level structures (cochlear nucleus, superior olivary complex, and inferior colliculus), alongside a shrinkage of solely the left medial geniculate body (MGB). Within the visual pathway, a significant bilateral volumetric reduction was found in the lateral geniculate nucleus, with the superior colliculus largely unaffected. These regional alterations, along with an extensive loss of volume throughout the brainstem of deprived cats, were attributed to disuse-driven atrophy corresponding to evolved functional demands reflective of a modified perceptual environment. Furthermore, the left-right volumetric symmetries of the control subcortex were preserved following deafness. Overall, the current study reinforces the notion that subcortical structures likely contribute to compensatory crossmodal plasticity prior to cortical processing, and that these deafness-induced adaptations appear to be influenced by both the level of the affected structure within its respective sensory processing hierarchy and the specifics of its afferent profile.

The perceptual primacy of feeling: Affectless visual machines explain a majority of variance in human visually evoked affect

Looking at the world often involves not just seeing things, but feeling things. Modern feedforward machine vision systems that learn to perceive the world in the absence of active physiology, deliberative thought, or any form of feedback that resembles human affective experience offer tools to demystify the relationship between seeing and feeling, and to assess how much of visually evoked affective experiences may be a straightforward function of representation learning over natural image statistics. In this work, we deploy a diverse sample of 180 state-of-the-art deep neural network models trained only on canonical computer vision tasks to predict human ratings of arousal, valence, and beauty for images from multiple categories (objects, faces, landscapes, art) across two datasets. Importantly, we use the features of these models without additional learning, linearly decoding human affective responses from network activity in much the same way neuroscientists decode information from neural recordings. Aggregate analysis across our survey, demonstrates that predictions from purely perceptual models explain a majority of the explainable variance in average ratings of arousal, valence, and beauty alike. Finer-grained analysis within our survey (e.g. comparisons between shallower and deeper layers, or between randomly initialized, category-supervised, and self-supervised models) point to rich, preconceptual abstraction (learned from diversity of visual experience) as a key driver of these predictions. Taken together, these results provide further computational evidence for an information-processing account of visually evoked affect linked directly to efficient representation learning over natural image statistics, and hint at a computational locus of affective and aesthetic valuation immediately proximate to perception.

Diagnostic Value of Gastrin-Releasing Peptide Receptor-Targeted PET Imaging in Oncology: A Systematic Review.

Gastrin-releasing peptide receptor (GRPR), overexpressed in various cancers, is a promising target for positron emission tomography (PET). This systematic review investigated the diagnostic value of GRPR-targeted PET imaging in oncology. A systematic search was conducted on major medical databases until May 23, 2024. Keywords were modified to include clinical original studies on GRPR-targeted PET in cancer patients. Out of 1624 searched studies initially, 107 were eligible for the full-text review. Overall, data from 38 studies met inclusion criteria, investigating GRPR-targeting radiotracers in breast cancer, prostate cancer, gastrointestinal stromal tumours (GIST) and gliomas (including optic pathway glioma and glioblastoma multiforme). In breast cancer, GRPR-targeted PET effectively detected primary tumours and metastases, particularly in estrogen receptor (ER)-positive patients, and predicted treatment response. In prostate cancer, high sensitivity (up to 88%) and specificity (up to 90%) for detecting primary tumours were observed, providing added value when combined with magnetic resonance imaging (MRI). In biochemical recurrence, sites of prostate cancer were identified even at PSA levels below 0.5ng/dL. Compared with PSMA PET, GRPR-targeted PET showed comparable or superior detection rates. Considering GIST, GRPR-targeted PET imaging proved to be a valuable diagnostic tool, particularly when [18F] FDG PET results were inconclusive. Regarding gliomas, GRPR-targeted PET achieved a 100% detection rate (MRI reference), aiding localization, preoperative planning, and differentiation between recurrence and malignant transformation. GRPR-targeted PET shows promise in improving cancer diagnostics, particularly in ER-positive breast cancer, prostate cancer, and gliomas, and may enhance clinical decision-making.

Retina-Inspired Flexible Visual Synaptic Device for Dynamic Image Processing.

Exploiting biomimetic perception of invisible spectra in flexible artificial human vision systems (HVSs) is crucial for real-time dynamic information processing. Nevertheless, the fast processing of motion objects in natural environments poses a challenge, necessitating that these artificial HVSs simultaneously have swift photoresponse and nonvolatile memory. Here, inspired by the human retina, we propose a flexible UV neuromorphic visual synaptic device (NeuVSD) based on GaOx@GaN-composited nanowires for dynamic visual perception. Benefiting from the combined action of oxygen adsorption kinetics on the GaOx shell and photoelectronic excitation in the GaN core, the NeuVSD can achieve rapid photoresponse and long-term plasticity simultaneously, a feature that surpasses traditional devices based on persistent photoconductivity mechanisms. Beyond the optoelectronic synaptic plasticity, the flexible NeuVSD on the PET/PI substrate exhibits good performance stability after 1000 bending cycles, profiting from the high adaptability of nanowires. Furthermore, target recognition and motion detection with weak light intensities are achieved through the establishment of neuromorphic visual neural networks, relying on dynamic exposures and edge information processing, respectively. Real-time edge detection can still be realized under a 40% noise factor and effectively remove the noise background. The flexible NeuVSD array-based artificial visual system can enhance the capability of dynamic visual information processing in low-light and high-noise conditions, thereby fostering the evolution of in-sensor computing and artificial intelligence.

Efficient Carbon-Based Optoelectronic Synapses for Dynamic Visual Recognition.

The human visual nervous system excels at recognizing and processing external stimuli, essential for various physiological functions. Biomimetic visual systems leverage biological synapse properties to improve memory encoding and perception. Optoelectronic devices mimicking these synapses can enhance wearable electronics, with layered heterojunction materials being ideal materials for optoelectronic synapses due to their tunable properties and biocompatibility. However, conventional synthesis methods are complex and environmentally harmful, leading to issues such as poor stability and low charge transfer efficiency. Therefore, it is imperative to develop a more efficient, convenient, and eco-friendly method for preparing layered heterojunction materials. Here, a one-step ultrasonic method is employed to mix fullerene (C60) with graphene oxide (GO), yielding a homogeneous layered heterojunction composite film via self-assembly. The biomimetic optoelectronic synapse based on this film achieves 97.3% accuracy in dynamic visual recognition tasks and exhibits capabilities such as synaptic plasticity. Experiments utilizing X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirms stable π-π interactions between GO and C60, facilitating electron transfer and prolonging carrier recombination times. The novel approach leveraging high-density π electron materials advances artificial intelligence and neuromorphic systems.

Dual-Mode ZnO/SnSe Heterojunction Devices with Integrated Bipolar Response Photodetectors and Artificial Optoelectronic Synapses for in-Sensor Computing.

Optoelectronic synapse devices (OESDs) inspired by human visual systems enable to integration of light sensing, memory, and computing functions, greatly promoting the development of in-sensor computing techniques. Herein, dual-mode integration of bipolar response photodetectors (PDs) and artificial optoelectronic synapses based on ZnO/SnSe heterojunctions are presented. The function of the fabricated device can be converted between the PDs and OESDs by modulating the light intensity. As a PD, the polarity of the output current can be switched by tuning the laser wavelength and intensity, which is attributed to the competition between the photovoltaic and photothermoelectric effects in the ZnO/SnSe heterojunction. As an OESD, the device exhibits versatile photonic synaptic characteristics at low light intensity based on the defect-dominant carrier trapping/de-trapping processes, including short/long-term plasticity and learning experience behaviors. More importantly, benefitting from the outstanding synaptic responses, logic functions including "AND" and "OR" are implemented through the in-sensor computing architecture. This work supplies a novel route to realize complex functionality in one device and offers effective strategies for developing in-sensor computing.

Gaze Stability Test Asymmetry Before and After Individualized Rehabilitation in Youth Athletes With Concussion.

Concussion causes physiological disruptions, including disruptions to the vestibular and visual systems, which can cause dizziness, imbalance, and blurry vision. The vestibular ocular reflex functions to maintain a stable visual field, which can be measured using the gaze stability test (GST). This preliminary study used retrospective chart review to examine changes in GST performance and asymmetry in a sample of 117 youth athletes with concussion (mean age = 14.51, SD = 2.08) before (T1) and after (T2) they completed a vestibular therapy program that included in-office treatment by a vestibular physical therapist and a customized home exercise program. Examples of exercises that may be assigned in the home exercise program during vestibular therapy are provided. After examining descriptive information, changes in GST scores and asymmetry percentage between time points were compared via Wilcoxon signed-rank tests. Results were also compared descriptively with previously published findings. Results revealed significant improvements in median GST in leftward and rightward direction head movements from T1 to T2 and a significant reduction in GST asymmetry (P < .001). Both GST in leftward and rightward direction head movements improved from 145.00 to 210.00°/s, which is above the 50th percentile in previously published literature with uninjured athletes. Asymmetry decreased from an average of 10.07% (SD = 7.89) to 4.11% (SD = 3.88), which is lower than in previously published literature. Concussion produces symptoms that vary among individuals and between injuries. GST velocity and asymmetry values provide objective data about an athlete's impairment and progress in recovery within the vestibular domain. This can aid in making clinical decisions on return to play progression and promote a successful and safe return to sport.

Cloud/VPN-Based Remote Control of a Modular Production System Assisted by a Mobile Cyber-Physical Robotic System-Digital Twin Approach.

This paper deals with a "digital twin" (DT) approach for processing, reprocessing, and scrapping (P/R/S) technology running on a modular production system (MPS) assisted by a mobile cyber-physical robotic system (MCPRS). The main hardware architecture consists of four line-shaped workstations (WSs), a wheeled mobile robot (WMR) equipped with a robotic manipulator (RM) and a mobile visual servoing system (MVSS) mounted on the end effector. The system architecture integrates a hierarchical control system where each of the four WSs, in the MPS, is controlled by a Programable Logic Controller (PLC), all connected via Profibus DP to a central PLC. In addition to the connection via Profibus of the four PLCs, related to the WSs, to the main PLC, there are also the connections of other devices to the local networks, LAN Profinet and LAN Ethernet. There are the connections to the Internet, Cloud and Virtual Private Network (VPN) via WAN Ethernet by open platform communication unified architecture (OPC-UA). The overall system follows a DT approach that enables task planning through augmented reality (AR) and uses virtual reality (VR) for visualization through Synchronized Hybrid Petri Net (SHPN) simulation. Timed Petri Nets (TPNs) are used to control the processes within the MPS's workstations. Continuous Petri Nets (CPNs) handle the movement of the MCPRS. Task planning in AR enables users to interact with the system in real time using AR technology to visualize and plan tasks. SHPN in VR is a combination of TPNs and CPNs used in the virtual representation of the system to synchronize tasks between the MPS and MCPRS. The workpiece (WP) visits stations successively as it is moved along the line for processing. If the processed WP does not pass the quality test, it is taken from the last WS and is transported, by MCPRS, to the first WS where it will be considered for reprocessing or scrapping.

Study on the quality of drug vial recognition and grasping and opening for pharmacy intravenous admixture robot based on nanophotonic sensing.

With the continuous progress of medical technology, traditional medicine bottle identification and management methods have problems such as low efficiency and large errors, and innovative solutions are urgently needed. Due to its high sensitivity and rapid response characteristics, this study aims to develop a robot system for intravenous infusion based on nanophotonics sensing to realize accurate identification, grasping and opening of medicine bottles in a dynamic environment, so as to improve the safety and efficiency of intravenous infusion. In this paper, an intelligent robot system with nanophotonics sensor is designed, which uses nanomaterials to produce high sensitivity sensor, so as to realize the information recognition of medicine bottle labels. The robot arm is set up to grasp and open the medicine bottle automatically through visual recognition system and feedback control algorithm. We conducted several rounds of experiments in a simulated environment to evaluate the recognition rate, grab success rate, and opening speed of the system. The experimental results show that the recognition system based on nano photonic sensor in bottle of accuracy and grab the success rate is higher, open time is greatly shortened, compared with traditional methods, the new system in recognition and operation were showed a significant advantage. The study demonstrates the potential of nanophotonics sensing technology in intravenous infusion robots. By optimizing the process of bottle recognition, grasping and opening, the system not only improves the safety and efficiency of medical operations, but is also expected to play a role in future medical automation. Future work will focus on further perfecting the system integration and optimization algorithm, so as to adapt to more complex clinical environment.

Metamorphopsia after surgery for rhegmatogenous retinal detachment.

Improvements in surgical techniques have led to 90% success in the surgical repair of rhegmatogenous retinal detachment (RRD). However, anatomical reattachment of the retina does not ensure complete recovery of visual function. The incidence of metamorphopsia remains the most common postoperative complaint, from 24% to 88.6%. Currently, the risk factors of metamorphopsia are categorized into macular involvement, retinal shift, outer retinal folds, subretinal fluid, secondary epiretinal membrane, outer retinal layer damage, and surgical approach. The associations of metamorphopsia with postoperative best-corrected visual acuity and postoperative vision-related quality of life were still controversial. The most popular methods for assessment of metamorphopsia remain the Amsler grid and M-Charts. Most treatments cannot progress beyond the management of negative visual sensations, through methods such as occlusion therapy and aniseikonia-correcting spectacles. The main treatment approach involves RRD prevention and the management of risk factors that can lead to postoperative metamorphopsia after RRD repair. Additional research concerning metamorphopsia treatment, further upgrades of auxiliary inspection methods, and more accurate microstructural assessments are needed to address this common complication.

A computer vision system for recognition and defect detection for reusable containers

Small load carriers (SLCs) are standardized reusable containers used to transport and protect customer goods in many manufacturers. Throughout the life cycle of the SLCs, they will be collected, manually checked for defects (wear, cracks, and residue on the surface), and cleaned by specialized logistic companies. Human operators in small to medium-sized companies manually evaluate the defects due to the variety and degree of possible defects and varying customer needs. This manual evaluation is not scalable and prone to errors. This work aims to fill this gap by proposing a computer vision system that can recognize the SLC type for inventory management and perform defect detection automatically. First, we develop a camera portal, consisting of standard components, that capture the relevant surfaces of the SLC. A labeled dataset of 17,530 images of 34 different SLCs with their defect status was recorded using this camera portal. We trained a classification model (ConvNeXt) using our dataset to predict the different types of SLCs achieving 100% class prediction accuracy. For defect detection, we explore eight state-of-the-art (SOTA) anomaly detection models that achieved high rankings in the MVTec industrial anomaly detection benchmark. These models are trained using default hyperparameters and the two highest-scoring models were chosen and fine-tuned. The best-fine-tuned models based on “Area under the Receiver Operating Characteristic Curve (AUROC)” are PatchCore (0.811) and DRAEM (0.748). These results indicate that there is still potential for improvement in the automation of defect detection of SLCs.

Comparison of biomechanical indices measured by ocular response analyzer between children and elderly: a systematic review.

Biomechanical study of the visual system by ocular response analyzer investigates the inter-structural biological relationships, mechanics, and function of the visual system. This review aimed to investigate the changes in corneal biomechanical parameters with age and sex. The articles published in PubMed between 2000 and 2021 were investigated and critiqued, and valid scientific evidence was collected, reviewed and concluded according to the inclusion and exclusion criteria. Most studies showed that corneal biomechanical changes occur infrequently in children up to the age of 20y, and with increasing age and wider age range, there was a significant decrease in corneal biomechanical indices, especially corneal hysteresis. In children and adults, most studies have shown that these biomechanical indicators, especially corneal resistance factor, were higher in females. Although hormonal changes may contribute to this finding, the role of axial length and other biometric indicators should not be ignored. The axial length, the intraocular pressure, and the corneal thickness are other factors associated with biomechanical parameters that should be taken into account in clinical diagnosis and management especially for patients undergoing refractive surgery as well as keratoconus patients.

Longitudinal assessment of retinal and visual pathway electrophysiology and structure after high altitude exposure.

High altitude (HA) exposure induces impairments in visual function. This study was designed to dynamically observe visual function after returning to lowland and elucidate the underlying mechanism by examining the structure and function of retina and visual pathway. Twenty-three subjects were recruited before (Test 1), and one week (Test 2) and three months (Test 3) after their return from HA (4300m) where they resided for 30 days. The clock task was used to assess visual cognition; and pattern-reversal visual evoked potential (p-VEP) and full-field electroretinogram (ff-ERG) were employed to record electrophysiological responses of retinal cells; optical coherence tomography (OCT), color doppler imaging (CDI) and magnetic resonance imaging(MRI) were used to measure structures of retina and visual pathway. In Test 2 vs. Test 1, there was increased reaction time during angle task; the amplitudes of scotopic 3.0cd·s/m2 and scotopic 10.0cd·s/m2 ERG a-wave and scotopic 3.0cd·s/m2 oscillatory potential in the right eye were significantly decreased, all of which were negatively correlated with the increased reaction time during the angle task. In Test 3 vs. Test 1, there were decreased amplitude of scotopic 10.0cd·s/m2 a-wave in the right eye and increased velocity of ophthalmic artery and ocular perfusion pressure in bilateral eyes. The VEP and visual pathway structures remained normal throughout the entire test. HA exposure caused damage to rod and cone responses in both outer and inner retina. After returning to sea level, the damaged visual cell functions gradually recovered over time, coinciding with an increase in the ocular perfusion.

Clinical predictors in acute optic neuritis: Analysis based on clinical trial data.

To identify baseline clinical predictors of visual outcomes six months after acute optic neuritis using data from our completed clinical neuroprotection trial (TONE study). Secondary analysis of data from the TONE study cohort (NCT01962571). Total of 103 patients presenting within 10 days of a first episode of acute unilateral optic neuritis as a clinically isolated syndrome with baseline high contrast visual acuity (HCVA) < 20/40 Snellen (logMAR 0.3). Patients were recruited from 12 German university hospitals between November 25th, 2014, and October 9th, 2017. We selected potential predictors based on literature research and experience, then computed initial linear regression models that each included one predictor together with the baseline value of the outcome of interest. We used a forward-selection approach to build a multiple regression model for each outcome. Since the trial medication of the TONE study (erythropoietin) had no effect on the visual system, we used pooled (treatment-agnostic) data for all analyses. Independent predictors of HCVA, low contrast letter acuity, visual-evoked potentials (VEP) P100 peak times, macular ganglion cell and inner plexiform layer thickness, and peripapillary retinal nerve fiber layer thickness at six months. On multiple regression, the most consistent predictors were higher baseline HCVA, which was associated with better outcomes across all measures except VEP conduction time; male sex, which predicted worse outcomes for all measures except HCVA; and older age, which was linked to poorer functional outcomes. Patients who are older, male, and present with worse initial visual function may be at risk for worse clinical outcomes in acute optic neuritis. This knowledge may inform individual patient counselling, facilitate patient selection for time-sensitive and invasive immunomodulatory treatments, and can be used to ensure balanced risk characteristics in clinical neuroprotection trials.

Differential impacts of strabismic and anisometropic amblyopia on the mesoscale functional organization of the human visual cortex.

We employed high-resolution fMRI to distinguish the impacts of anisometropia and strabismus amblyopia on the evoked ocular dominance (OD) response. Sixteen amblyopic participants (8 females) plus 8 individuals with normal vision (1 female), participated in this study for whom, we measured the difference between the response to stimulation of the two eyes, across areas V1-V4.In controls, the evoked OD response formed the expected striped pattern within V1. Compared to controls, the OD response in amblyopic participants formed larger fused patches that extended into downstream visual areas. Moreover, both anisometropic and strabismic participants showed elevated OD responses across V1-V4.Beyond these common effects, and despite similar densities of amblyopia between the two groups, strabismus and anisometropia had differential impacts on the OD bias, binocular response and correlation between V1 depth levels. Specifically, we found a greater increase in the size of V1 portion that responded preferentially to fellow eye stimulation in anisometropic compared to strabismic individuals. We also found a greater difference between the amplitudes of the response to binocular stimulation, in those regions that responded preferentially to the fellow vs. amblyopic eye, in anisometropic compared to strabismic participants. In contrast, strabismic participants demonstrated increased correlation between the OD responses evoked within V1 superficial and deep depths, whereas anisometropic individuals did not.These results provide the primary direct functional evidence for distinct impacts of strabismus and anisometropia on the mesoscale functional organization of the human visual system, thus extending what was inferred previously about amblyopia from animal models.Significance Statement Amblyopia is a developmental disorder caused by perturbations to normal binocular visual experience during the critical period impact. Despite its high prevalence, our current understanding of amblyopia impacts on the mesoscale functional organization of primary visual area (V1) is mostly based on invasive techniques in animals. In this study we showed the primary direct evidence for the distinct impacts of anisometropia versus strabismus (two major causes of amblyopia) on the fMRI activity evoked within the human visual cortex. Our findings also confirmed the hypothesized link between the evoked OD response and the interocular visual acuity difference in amblyopia.

1950s-1990s: The pioneering era of insect neuroscience in Uruguay.

Insect research has significantly advanced neuroscience by addressing fundamental questions, with groundbreaking discoveries emerging from research carried out in Uruguay. Powered by technological advances, the field has seen milestones in ultrastructure, neuronal and synaptic structure, and complex behavioral findings. Key contributions include the first formal description of chemical synapses, the identification of synaptic vesicle origins in the endoplasmic reticulum, and pioneering work on eye induction and development. Uruguay's research has also provided critical insights into neural degeneration and repair mechanisms, the functional microanatomy of the visual pathway, and mechanoreception. This review highlights four decades of Uruguayan legacy in insect neuroscience, underscoring how a small, yet vibrant, community of researchers has embraced interdisciplinary collaborations and innovative methodologies. Additionally, this review addresses the evolving role of women in the field and the collaborative spirit that has propelled scientific discovery, marking a critical juncture in the development of insect neuroscience. Despite limited resources, Uruguay has played a pivotal role in advancing our understanding of brain organization, neuronal-glial interactions, and connectomics, making lasting contributions to both local and global neuroscience.

Virtual Human Retina: Simulating Neural Signalling, Degeneration, and Responses to Electrical Stimulation.

Current brain-based visual prostheses pose significant challenges impeding adoption such as the necessarily complex surgeries and occurrence of more substantial side effects due to the sensitivity of the brain. This has led to much effort toward vision restoration being focused on the more approachable part of the brain - the retina. Here we introduce a novel, parameterized simulation platform that enables study of human retinal degeneration and optimization of stimulation strategies. The platform bears immense potential for patient-specific tailoring and serves to enhance artificial vision solutions for individuals with visual impairments. Our virtual retina is developed using the software package, NEURON. This virtual retina platform supports large-scale simulations of over 10,000 neurons whilst upholding strong biological plausibility with multiple important visual pathways and detailed network properties. The comprehensive three-dimensional model includes photoreceptors, horizontal cells, bipolar cells, amacrine cells, and midget and parasol retinal ganglion cells, with comprehensive network connectivity across various eccentricities (1 mm to 5 mm from the fovea) in the human retina. The model is constructed using electrophysiology, immunohistology, and optical coherence tomography imaging data from healthy and degenerate human retinas. We validated our model by replicating numerous experimental observations from human and primate retina, with a particular focus on retinal degeneration. We simulated interactions between diseased retinas and state-of-the-art retinal implants, shedding light on the limitations of commercial retinal prostheses. Our results suggested that appropriate stimulation settings with intraretinal prototype devices could leverage network-mediated activation to achieve activation mosaics more alike that of the retina's response to natural light, promoting the prospect of more naturalistic vision. Our study additionally highlights the importance of controlling inhibitory circuits in the retinal network to induce functionally relevant retinal activity. This study demonstrates the potential of this software package and highlights its utility as a valuable tool for engineers, scientists, and clinicians in the design and optimisation of retinal stimulation devices for both research and educational applications.

Adaptation optimizes sensory encoding for future stimuli.

Sensory neurons continually adapt their response characteristics according to recent stimulus history. However, it is unclear how such a reactive process can benefit the organism. Here, we test the hypothesis that adaptation actually acts proactively in the sense that it optimally adjusts sensory encoding for future stimuli. We first quantified human subjects' ability to discriminate visual orientation under different adaptation conditions. Using an information theoretic analysis, we found that adaptation leads to a reallocation of coding resources such that encoding accuracy peaks at the mean orientation of the adaptor while total coding capacity remains constant. We then asked whether this characteristic change in encoding accuracy is predicted by the temporal statistics of natural visual input. Analyzing the retinal input of freely behaving human subjects showed that the distribution of local visual orientations in the retinal input stream indeed peaks at the mean orientation of the preceding input history (i.e., the adaptor). We further tested our hypothesis by analyzing the internal sensory representations of a recurrent neural network trained to predict the next frame of natural scene videos (PredNet). Simulating our human adaptation experiment with PredNet, we found that the network exhibited the same change in encoding accuracy as observed in human subjects. Taken together, our results suggest that adaptation-induced changes in encoding accuracy prepare the visual system for future stimuli.

GravelSens: A Smart Gravel Sensor for High-Resolution, Non-Destructive Monitoring of Clogging Dynamics.

Engineers, geomorphologists, and ecologists acknowledge the need for temporally and spatially resolved measurements of sediment clogging (also known as colmation) in permeable gravel-bed rivers due to its adverse impacts on water and habitat quality. In this paper, we present a novel method for non-destructive, real-time measurements of pore-scale sediment deposition and monitoring of clogging by using wire-mesh sensors (WMSs) embedded in spheres, forming a smart gravel bed (GravelSens). The measuring principle is based on one-by-one voltage excitation of transmitter electrodes, followed by simultaneous measurements of the resulting current by receiver electrodes at each crossing measuring pores. The currents are then linked to the conductive component of fluid impedance. The measurement performance of the developed sensor is validated by applying the Maxwell Garnett and parallel models to sensor data and comparing the results to data obtained by gamma ray computed tomography (CT). GravelSens is tested and validated under varying filling conditions of different particle sizes ranging from sand to fine gravel. The close agreement between GravelSens and CT measurements indicates the technology's applicability in sediment-water research while also suggesting its potential for other solid-liquid two-phase flows. This pore-scale measurement and visualization system offers the capability to monitor clogging and de-clogging dynamics within pore spaces up to 10,000 Hz, making it the first laboratory equipment capable of performing such in situ measurements without radiation. Thus, GravelSens is a major improvement over existing methods and holds promise for advancing the understanding of flow-sediment-ecology interactions.

Complementary Organization of Mouse Driver and Modulator Cortico-Thalamo-Cortical Circuits.

Corticocortical (CC) projections in the visual system facilitate hierarchical processing of sensory information. In addition to direct CC connections, indirect cortico-thalamo-cortical (CTC) pathways through the pulvinar nucleus of the thalamus can relay sensory signals and mediate cortical interactions according to behavioral demands. While the pulvinar connects extensively to the entire visual cortex, it is unknown whether transthalamic pathways link all cortical areas or whether they follow systematic organizational rules. Because mouse pulvinar neurons projecting to different areas are spatially intermingled, their input/output relationships have been difficult to characterize using traditional anatomical methods. To determine the organization of CTC circuits, we mapped the higher visual areas (HVAs) of male and female mice with intrinsic signal imaging and targeted five pulvinar→HVA pathways for projection-specific rabies tracing. We aligned post-mortem cortical tissue to in vivo maps for precise quantification of the areas and cell types projecting to each pulvinar→HVA population. Layer 5 corticothalamic (L5CT) "driver" inputs to the pulvinar originate predominantly from primary visual cortex (V1), consistent with the CC hierarchy. L5CT inputs from lateral HVAs specifically avoid driving reciprocal connections, consistent with the "no-strong-loops" hypothesis. Conversely, layer 6 corticothalamic (L6CT) "modulator" inputs are distributed across areas and are biased toward reciprocal connections. Unlike previous studies in primates, we find that every HVA receives disynaptic input from the superior colliculus. CTC circuits in the pulvinar thus depend on both target HVA and input cell type, such that driving and modulating higher-order pathways follow complementary connection rules similar to those governing first-order CT circuits.Significance statement Understanding the function of the pulvinar will require knowledge of its anatomical connections. Using state-of-the-art rabies tracing, we establish a map of brain-wide and CTC pulvinar connections. While the primate tectopulvinar pathway selectively targets dorsal visual areas, we find ubiquitous SC input in the mouse. This extrageniculate projection supports unconscious visually-guided behavior, suggesting that all visual cortical areas contribute to such functions in mice. Our results also unify longstanding anatomical hypotheses. Namely, "driver" CTC inputs are feedforward relays and adhere to the "no-strong-loops" hypothesis. "Modulator" L6CT inputs are overrepresented in the target HVA, reflecting the reciprocal connectivity described in previous bulk tracing studies. Together, these findings constitute a comprehensive map to guide future experimental and theoretical studies of pulvinar function.