Biology subjects

Lau, H.

Publications and source records attributed to Lau, H..

At least 19 recordsLinked to original sources

bioRxiv2026

Perceptual similarity representations beyond the sensory cortex

It is commonly thought that information supporting conscious perception is primarily represented in sensory cortices, whereas association cortex encodes more abstract, task-dependent information. However, this impression may partly stem from difficulties in experimentally assessing the functions of association areas characterized by mixed selectivity and complex spatial topography. Here, we combined repetition-suppression (RS) and multi-voxel pattern analysis (MVPA) to extract richer information from human fMRI. With this approach, we asked whether association regions represent the perceptual similarity structure among color stimuli, although this perceptual similarity information was task-irrelevant in the experiment. Our analysis revealed such representations beyond the visual cortex, in lateral prefrontal, and parietal regions. We further demonstrated an electrophysiological complement to the fMRI findings by applying the same approach to local field potentials recorded in the macaque dorsomedial parietal cortex. Our findings suggest that higher-order areas beyond the visual cortex may play a key role in subjective color perception.

neuroscience↗

bioRxiv2026

Bidirectional modulation of pain by neurofeedback: Preliminary findings with fMRI at 7T

Previous brain decoding studies indicate that an individuals pain experience can be robustly predicted from distributed patterns of brain activity. Two brain decoders have notably been associated respectively with the nociceptive and cognitive aspects of pain experience, the Neurologic Pain Signature (NPS) and the Stimulus-Intensity Independent Pain Signature (SIIPS). Yet, we still do not know if these brain patterns are also causally related to pain experience. To evaluate this possibility, we used high-field (7-Tesla) fMRI to test whether humans can alter their pain experience by bidirectionally modulating their pain-related brain activity in decoded neurofeedback paradigm. In a double-blind design, participants were trained to up- and down-regulate the NPS or the SIIPS. Our results indicate that participants can achieve bidirectional control of both signatures. NPS expression reliably increased during pain stimulation and covaried with both stimulus intensity and subjective ratings. In contrast, SIIPS expression did not show consistent stimulus-locked effects in the primary analyses. Importantly, reduction in pain rating was specific for SIIPS-training, whereas NPS has failed to show any consistent behavioral effect. Based on these preliminary findings, we hereby preregister a follow-up study, with specified rationale, hypotheses, experimental design, and analysis protocols.

neuroscience↗

bioRxiv2025

Working Memory Selectively Modulates Subjective Perception: A Pilot Study

The present study demonstrates a blindsight-like dissociation between subjective perception and general perceptual capacity in nonclinical observers. Participants performed either a two-interval forced-choice (2-IFC) or a Yes/No face detection task during working memory delay. To match general perceptual processing capacity across conditions, we titrated stimulus luminance contrast in the 2-IFC task and applied the same contrast in the Yes/No task. In Experiment 1, categorically incongruent (i.e., scene) information held in working memory impaired the sensitivity of the Yes/No detection of stimulus presence (face) vs. absence (blank background). In contrast, this effect was absent in Experiment 2, in which the Yes/No task required a discrimination of a face (target) vs. a scrambled face (non-target). These findings indicate that stimulus incongruency in working memory selectively influences subjective perception, dissociating it from general perceptual capacity.

neuroscience↗

bioRxiv2025

Surveillance of migratory shorebirds and seabirds in 2024 in Australia reveals incursions of a diversity of low pathogenicity avian influenza viruses, but not high pathogenicity avian influenza H5N1

The current panzootic of high pathogenicity avian influenza (HPAI) H5N1 has been catastrophic for wildlife, and following a significant sweep, clade 2.3.4.4b is found in every region aside from Oceania. Herein, we report the results of our third year of targeted surveillance of incoming migratory seabirds and shorebirds into Australia. We did not find evidence of HPAI H5N1 in any of the birds tested, and there were no reports of HPAI H5N1 in wildlife tested through other surveillance schemes in 2024. Unlike previous years, we detected a diversity of low pathogenicity avian influenza (LPAI) viruses in shorebirds. Through phylogenetic analysis we revealed that the H3N7 and H4N7 viruses recovered from Red-necked Stints were complex mosaic viruses, comprising segments of Eurasian, Australian shorebird, and Australian waterfowl segments. A H1N7 virus detected comprised a wholly Eurasian introduction, confirming this route for avian influenza viruses into Australian ecosystems. These results provide further evidence for the key role of long-distance migratory shorebirds in introducing novel LPAI viruses into Oceania. While our focus on northern migration routes remained appropriate for HPAI H5N1 surveillance in 2024, the continued spread of HPAI H5N1 to sub-Antarctic Islands demands consideration of a potential southern incursion route for Oceania in future.

microbiology↗

bioRxiv2025

Trait motivation is associated with Fusiform face area Morphometry Evidence from a Chinese Youth Sample

Trait motivation is fundamental in shaping human behaviors. Previous studies have primarily focused on their impact on affective and motivational processing, with their role in perceptual processes less investigated. The present study takes face perception, a crucial and well-studied perceptual process, as a representative specimen to examine the perceptual effect of trait motivation. We investigated whether the behavioral activation system (BAS) and the behavioral inhibition system (BIS) were associated with structural characteristics of the inferior temporal face-selective regions as well as face recognition performance. With a sample of Chinese young adults (N = 264), voxel-based morphometry revealed that BIS scores correlated with greater gray matter volume in the fusiform face area. Further, a higher BIS score was associated with slightly better performance in face recognition. These findings provide novel evidence that trait motivation, particularly behavioral inhibition, is linked to both the structure and function of the face processing system. This underlines the intrinsic coupling between motivational and perceptual systems, blurring the presumed divide between affective and perceptual processes.

neuroscience↗

bioRxiv2025

Representational Geometries of Perception and Working Memory: A Pilot Study

This study examined the representational geometry of visual working memory using human 7T fMRI. Observers viewed a facescene blended sample, attended to either the face or scene, and judged whether the attended aspect matched a subsequent test image. We found that the coding dimension distinguishing faces and scenes rotated between encoding and maintenance phases, in both visual and association areas. In these regions, exclusive combinations (i.e., encoded face and maintained scene vs. encoded scene and maintained face) were linearly decodable, indicating encoding and maintenance phases represent visual information using distinct subspaces. Such high-dimensional, flexible geometry can, in principle, protect maintained visual information from incoming input. At the same time, robust crossdecoding was observed across phases, reflecting the stability and generalizability of the represented contents. The balance between representational flexibility and stability varied along the cortical hierarchy: early sensory regions emphasized flexibility, whereas transmodal regions showed greater stability.

neuroscience↗

bioRxiv2025

Attention robustly dissociates objective performance and subjective visibility reports

Visual experience can sometimes depart from visual performance, providing a powerful lens into the mechanisms generating conscious perception. In one proposed dissociation--subjective inflation--unattended locations in the periphery appear stronger than attended ones despite equated performance. Subjective inflation has played a central role in motivating theories of consciousness that reject the sufficiency of sensory signals for conscious perception. Yet the empirical basis for subjective inflation is limited. Here, in a large-scale adversarial collaboration, we conducted four simultaneously-replicated experiments testing the strength, character, and extent of subjective inflation under inattention. We used a new analytic approach to quantify inattentional inflation over full psychometric functions, beyond single matched-performance levels. We found robust inattentional inflation for contrast-dependent and texture-based perception, at and above the visual threshold. However at suprathreshold, we found inattentional inflation for the overall stimulus but not the specific feature relevant for performance. Finally, we establish the unifying principle that inattentional inflation occurs if and only if attention reduces performance thresholds more than visibility thresholds. Thus what we think we see may regularly exceed what we can visually discriminate, placing constraints on theories of conscious perception.

neuroscience↗

bioRxiv2025

Assessing the Effectiveness of 3D-Printed Ceramic Structures for Coral Restoration: Growth, Survivorship, and Biodiversity Using Visual Surveys and eDNA

Coral reef degradation has spurred the development of artificial structures to mitigate losses in coral cover. These structures serve as substrates for coral transplantation, with the expectation that growing corals will attract reef-associated taxa -- while the substrates ability to directly support biodiversity is often neglected. We evaluated a novel 3D-printed modular tile made of porous terra cotta, designed with complex surface structures to enhance micro- and cryptic biodiversity, through a restoration project in Hong Kong. Over four years, we monitored 378 outplanted coral fragments using diver assessments and photography, while biodiversity changes were assessed through visual surveys and eDNA metabarcoding. Coral survivorship was high, with 88% of transplants surviving by the studys end. The restoration site exhibited greater fish and macroinvertebrate abundance compared to a nearby unrestored area. eDNA analyses revealed 23.5% higher eukaryote ASV richness at the restoration site than the unrestored site and a 13.3% increase relative to a natural reference coral community. This study highlights the tiles dual functionality: (1) supporting coral growth and (2) enhancing cryptic biodiversity, an aspect often neglected in traditional reef restoration efforts. Our findings underscore the potential of 3D-printed ceramic structures to improve both coral restoration outcomes and broader reef ecosystem recovery.

ecology↗

bioRxiv2024

Rapid Sterilization of Clinical Apheresis Blood Products using Ultra-High Dose Rate Radiation

BACKGROUND AND OBJECTIVESApheresis platelets products and plasma are essential for medical interventions, but both still have inherent risks associated with contamination and viral transmission. Platelet products are vulnerable to bacterial contamination due to storage conditions, while plasma requires extensive screening to minimize virus transmission risks. Here we investigate rapid irradiation to sterilizing doses for bacteria and viruses as an innovative pathogen reduction technology. MATERIALS AND METHODSWe configured a clinical linear accelerator to deliver ultra-high dose rate (6 kGy/min) irradiation to platelet and plasma blood components. Platelet aliquots spiked with 105 CFU of E.coli were irradiated with 0.1-20 kGy, followed by E.coli growth and platelet count assays. COVID Convalescent Plasma (CCP) aliquots were irradiated at a virus-sterilizing dose of 25 kGy and subsequently, RBD- specific antibody binding was assessed. RESULTS1 kGy irradiation of bacteria-spiked platelets reduced E.coli growth by 2.7- log without significant change of platelet count, and 5 kGy or higher produced complete growth suppression. The estimated sterilization (6-log bacterial reduction) dose was 2.3 kGy, corresponding to 31% platelet count reduction. A 25 kGy virus sterilizing dose to CCP produced a 9.2% average drop of RBD-specific IgG binding. CONCLUSIONThis study shows proof-of-concept of a novel rapid blood sterilization technique using a clinical linear accelerator. Promising platelet counts and CCP antibody binding were maintained at bacteria and virus sterilizing doses, respectively. This represents a potential point-of-care blood product sterilization solution. If additional studies corroborate these findings, this may be a practical method for ensuring blood products safety. HIGHLIGHTSO_LI1 kGy irradiation of bacteria-spiked platelets reduced E.coli growth by 2.7-log without significant change of platelet count, and 5 kGy or higher produced complete growth suppression. C_LIO_LIThe estimated sterilization (6-log bacterial reduction) dose was 2.3 kGy, corresponding to 31% platelet count reduction. C_LIO_LIA 25 kGy virus sterilizing dose to CCP produced a 9.2% average drop of RBD- specific IgG binding. C_LI

microbiology↗

bioRxiv2024

Representation of visual uniformity in the lateral prefrontal cortex

Visual illusions tend to have early visual cortical correlates. However, this general trend may not apply to our subjective impression of a detailed and uniform visual world, which may be considered illusory given the paucity of peripheral processing. Using a psychophysically calibrated visual illusion, we assessed the patterns of hemodynamic activity in the human brain that distinguished between the illusory percept of uniformity in the periphery (i.e., Gabor patches having identical orientations) from the accurate perception of incoherence. We identified voxel patterns in the lateral prefrontal cortex that predicted perceived uniformity, which could also generalize to scene uniformity in naturalistic movies. Because similar representations of visual uniformity can also be found in the intermediate and late layers of a feedforward convolutional neural network, the perception of uniformity may involve high-level coding of abstract properties of the entire scene as a whole, that is distinct from the filling-in of specific details in early visual areas.

neuroscience↗

bioRxiv2024

Is subjective perceptual similarity metacognitive?

Perceptual similarity is a cornerstone for human learning and generalization. However, in assessing perceptual similarity between two stimuli, it is not well-defined which features or combinations of features one should focus on. The problem has accordingly been considered ill-posed, implying a lack of a clear ground-truth basis for similarity judgments. We hypothesized that the stimuli rated as subjectively similar are those that are, in fact, more challenging for oneself to discern in practice, in near-threshold settings (e.g., psychophysics experiments). Therefore, an individuals perceptual discrimination capacities can serve as a quasi-objective ground truth for determining whether two stimuli should be judged as similar. To test this idea, we asked participants to rank the similarity of face pairs and also separately measured their discrimination capacity for those pairs. We found a positive association between perceptual discrimination capacity and subjective perceptual dissimilarity, with this association being specific to each individual. The results indicate that perceptual similarity judgments reflect and predict ones own perceptual discrimination capacities. Overall, although subjective, similarity judgments are normative in that they are grounded in ones perceptual capacities, which can be measured through a psychophysical task with objective responses.

neuroscience↗

bioRxiv2024

Individual differences in prefrontal coding of visual features

Each of us perceives the world differently. What may underlie such individual differences in perception? Here, we characterize the lateral prefrontal cortexs role in vision using computational models, with a specific focus on individual differences. Using a 7T fMRI dataset, we found that encoding models relating visual features extracted from a deep neural network to brain responses to natural images robustly predict responses in patches of LPFC. We then explored the representational structures and screened for images with high predicted responses in LPFC. We observed more substantial individual differences in the coding schemes of LPFC compared to visual regions. Computational modeling suggests that the amplified individual differences could result from the random projection between sensory and high-level regions underlying flexible working memory. Our study demonstrates the under-appreciated role of LPFC in visual processing and suggests that LPFC may underlie the idiosyncrasies in how different individuals experience the visual world.

neuroscience↗

bioRxiv2023

Modulating Subjective Pain Perception with Decoded MNI-space Neurofeedback

Pain is a complex emotional experience that still remains challenging to manage. Previous functional magnetic resonance imaging (fMRI) studies have associated pain with distributed patterns of brain activity (i.e., brain decoders), but it is still unclear whether these observations reflect causal mechanisms. To address this question, we devised a new neurofeedback approach leveraging real-time decoding of fMRI data to test if modulating pain-related multivoxel fMRI patterns could lead to changes in subjective pain experience. We first showed that subjective pain ratings can indeed be accurately predicted using a real-time decoding approach based on the stimulus intensity independent pain signature (SIIPS) and the neurologic pain signature (NPS). Next, we trained participants in a double-blinded decoded fMRI neurofeedback experiment to up- or down-regulate the SIIPS. Our results indicate that participants can learn to down-regulate the expression of SIIPS independently from NPS expression. Importantly, the success of this neurofeedback training was associated with the perceived intensity of painful stimulation following the intervention. Taken together, these results indicate that closed-loop brain imaging can be efficiently conducted using a priori fMRI decoders of pain, potentially opening up a new range of applications for decoded neurofeedback, both for clinical and basic science purposes.

neuroscience↗

bioRxiv2023

Multi-modal skin atlas associates a multicellular immune-stromal community with altered cornification and T cell expansion in atopic dermatitis

In healthy skin, a cutaneous immune system maintains the balance between tolerance towards innocuous environmental antigens and immune responses against pathological agents. In atopic dermatitis (AD), barrier and immune dysfunction result in chronic tissue inflammation. Our understanding of the skin tissue ecosystem in AD remains incomplete with regard to the hallmarks of pathological barrier formation, and cellular state and clonal composition of disease-promoting cells. Here, we generated a multi-modal cell census of 310,691 cells spanning 86 cell subsets from whole skin tissue of 19 adult individuals, including non-lesional and lesional skin from 11 AD patients, and integrated it with 396,321 cells from four studies into a comprehensive human skin cell atlas in health and disease. Reconstruction of human keratinocyte differentiation from basal to cornified layers revealed a disrupted cornification trajectory in AD. This disrupted epithelial differentiation was associated with signals from a unique immune and stromal multicellular community comprised of MMP12+ dendritic cells (DCs), mature migratory DCs, cycling ILCs, NK cells, inflammatory CCL19+ IL4I1+ fibroblasts, and clonally expanded IL13+IL22+IL26+ T cells with overlapping type 2 and type 17 characteristics. Cell subsets within this immune and stromal multicellular community were connected by multiple inter-cellular positive feedback loops predicted to impact community assembly and maintenance. AD GWAS gene expression was enriched both in disrupted cornified keratinocytes and in cell subsets from the lesional immune and stromal multicellular community including IL13+IL22+IL26+ T cells and ILCs, suggesting that epithelial or immune dysfunction in the context of the observed cellular communication network can initiate and then converge towards AD. Our work highlights specific, disease-associated cell subsets and interactions as potential targets in progression and resolution of chronic inflammation.

molecular biology↗

bioRxiv2023

Interaction Between the Prefrontal and Visual Cortices Supports Subjective Fear

It has been reported that threatening and non-threatening visual stimuli can be distinguished based on the multi-voxel patterns of hemodynamic activity in the human ventral visual stream. Do these findings mean that there may be evolutionarily hardwired mechanisms within early perception, for the fast and automatic detection of threat, and maybe even for the generation of the subjective experience of fear? In this human neuroimaging study, we presented participants (Fear group: N=30; No Fear group: N = 30) with 2700 images of animals that could trigger subjective fear or not as a function of individuals idiosyncratic "fear profiles" (i.e., fear ratings of animals reported by a given participant). We provide evidence that the ventral visual stream may represent affectively neutral visual features that are statistically associated with fear ratings of participants, without representing the subjective experience of fear itself. More specifically, we show that patterns of hemodynamic activity predictive of a specific "fear profile" can be observed in the ventral visual stream whether a participant reports being afraid of the stimuli or not. Further, we found that the multivariate information synchronization between ventral visual areas and prefrontal regions distinguished participants who reported being subjectively afraid of the stimuli from those who did not. Together, these findings support the view that the subjective experience of fear may depend on the relevant visual information triggering implicit metacognitive mechanisms in the prefrontal cortex.

neuroscience↗

bioRxiv2021

Performance-optimized neural networks as an explanatory framework for decision confidence

Previous work has sought to understand decision confidence as a prediction of the probability that a decision will be correct, leading to debate over whether these predictions are optimal, and whether they rely on the same decision variable as decisions themselves. This work has generally relied on idealized, low-dimensional models, necessitating strong assumptions about the representations over which confidence is computed. To address this, we used deep neural networks to develop a model of decision confidence that operates directly over high-dimensional, naturalistic stimuli. The model accounts for a number of puzzling dissociations between decisions and confidence, reveals a rational explanation of these dissociations in terms of optimization for the statistics of sensory inputs, and makes the surprising prediction that, despite these dissociations, decisions and confidence depend on a common decision variable.

neuroscience↗

bioRxiv2021

Single-shot rAAV5-based Vaccine Provides Long-term Protective Immunity against SARS-CoV-2 and Its Variants

The COVID-19 pandemic and the SARS-CoV-2 with its variants have posed unprecedented challenges worldwide. Existing vaccines have limited effectiveness against the SARS-CoV-2 variants. Therefore, novel vaccines to match current mutated viral lineages with long-term protective immunity are urgently in demand. In the current study, we for the first time designed a recombinant Adeno-Associated Virus 5 (rAAV5)-based vaccine named as rAAV-COVID-19 vaccine (Covacinplus) by using RBD-plus of spike protein with both the single-stranded and the self-complementary AAV5 delivering vectors (ssAAV5 and scAAAV5), which provides excellent protection from SARS-CoV-2 infection. A single dose vaccination induced the strong immune response against SARS-CoV-2. The induced neutralizing antibodies (NAs) titers were maintained at a high peak level of over 1:1024 even after more than one year of injection and accompanied with functional T-cells responses in mice. Importantly, both ssAAV- and scAAV-based RBD-plus vaccines exhibited high levels of serum NAs against current circulating variants including variants Alpha, Beta, Gamma and Delta. SARS-CoV-2 virus challenge test showed that ssAAV5-RBD-plus vaccine protected both young and old age mice from SARS-CoV-2 infection in the upper and the lower respiratory tracts. Moreover, whole genome sequencing demonstrated that AAV vector DNA sequences were not found in the genome of the vaccinated mice after one year vaccination, demonstrating excellent safety of the vaccine. Taken together, this study suggests that rAAV5-based vaccine is powerful against SARS-CoV-2 and its variants with long-term protective immunity and excellent safety, which has great potential for development into prophylactic vaccination in human to end this global pandemic.

immunology↗

bioRxiv2020

Between-subject correlation of heart rate variability predicts movie preferences

We introduce a novel and simple method for assessing audiences emotional responses to audiovisuals (e.g. films). Viewers (N=21) watched movies and TV commercials from different genres while wearing photoplethysmography (PPG) optic sensors on their wrists. Heart rate variability (HRV) synchrony was observed among the audience. Based on this between-subject synchrony measure, we identified emotionally arousing segments from the materials. New participants (N=24; N=16) were then invited to watch these identified segments along with some randomly selected segments as control; they reported that the former was more engaging (effect size w=.67; w=.5). This finding was confirmed in an online study with a larger cohort (N=300). While some specific effects varied depending on movie genre or gender, HRV-based editing generally performed better than the control. These findings suggest that HRV synchrony can be used as a new tool for audience psychology, and potentially also for automatically creating short trailers out of movies in a principled manner while taking into account the human perspective.

neuroscience↗