Biology subjects

Davidson, H.

Publications and source records attributed to Davidson, H..

5 recordsLinked to original sources

bioRxiv2025

Investigating Facial Expression Processing during Fast Periodic Visual Stimulation using Highly Variable Stimuli

Facial expression recognition is a fundamental aspect of human social interaction, enabling effective communication and emotional understanding. Fast Periodic Visual Stimulation (FPVS) paradigms have recently emerged as a powerful approach for studying facial expression processing. However, previous studies often utilized identical base stimuli, making it difficult to disentangle neural responses to low-level perceptual differences from those reflecting conceptual discrimination of emotion. By introducing variability in our stimuli, we aimed to overcome these limitations and investigate neural responses to facial expressions of anger, fear, happiness, and sadness. Using EEG, robust oddball responses were observed across participants at both individual and group levels, demonstrating the paradigms sensitivity even with brief recordings and limited post-processing. Significant neural responses were detected across key regions of interest, with the right occipito-temporal region showing the strongest activity, consistent with its role in high-level facial expression processing. This study highlights the effectiveness of the FPVS paradigm for examining emotional processing using naturalistic stimuli and provides a framework for future research into neural mechanisms underlying facial emotion recognition in diverse and pathological populations.

neuroscience↗

bioRxiv2025

Reduced Fast Periodic Visual Stimulation Oddball Responses to Threatening Faces Associated with Anxiety

Facial expression processing is crucial for social communication and survival, with anxiety disorders often linked to alterations in attentional biases toward threat-related stimuli. While previous studies using event-related potentials (ERPs) have yielded conflicting findings regarding threat sensitivity in anxiety, Fast Periodic Visual Stimulation (FPVS) offers a high signal-to-noise, implicit alternative for assessing emotion processing. This study utilized FPVS to investigate neural responses to facial expressions in individuals with elevated anxiety-related characteristics (e.g., prior diagnosis or elevated symptom scores) and those without. EEG responses were recorded while participants viewed sequences of neutral faces interspersed with emotional oddball expressions (angry, fearful, happy, and sad). Results revealed robust neural discrimination responses to all facial expressions. Participants with anxiety-related characteristics showed significantly greater summed baseline-corrected amplitudes (BCA) at occipital electrodes in response to angry and sad oddball faces compared to the low-anxiety group. This was accompanied by reduced top-down interactions. Although, dimensional anxiety scores were generally low, suggesting results may reflect residual or trait-level differences rather than acute symptomatology, these findings provide preliminary evidence that FPVS may be sensitive to enduring differences in emotion processing associated with anxiety vulnerability.

neuroscience↗

bioRxiv2025

Implicit Emotional Biases in Anxiety and Depression: A Fast Periodic Visual Stimulation Study

Anxiety and depression are among the leading global causes of disability, yet their underlying neural mechanisms remain poorly understood. Traditional event-related potential (ERP) studies have shown attentional biases in anxiety and blunted responses to positive stimuli in depression, but limitations in sensitivity and interpretability hinder their clinical application. Fast Periodic Visual Stimulation (FPVS) offers an objective, high signal-to-noise ratio (SNR) approach to measuring neural responses to emotional stimuli. In this study, we applied FPVS with affective images to assess differences in emotional processing between individuals with anxiety and healthy controls across two experimental phases, optimizing stimulus presentation parameters. The results revealed that individuals with anxiety exhibited increased neural responses to negative stimuli compared to positive stimuli, as well as reduced responses to high-arousal stimuli, particularly in occipito-temporal and central-parietal regions. Additionally, individuals with comorbid depression showed blunted responses to high-arousal stimuli across multiple brain regions, consistent with reduced emotional reactivity. These findings support the feasibility of FPVS as a rapid and reliable tool for assessing emotional processing differences in clinical populations, with potential applications in translational research and psychiatric screening

neuroscience↗

bioRxiv2023

Cancer Prevalence Across Vertebrates

Cancer is pervasive across multicellular species, but what explains differences in cancer prevalence across species? Using 16,049 necropsy records for 292 species spanning three clades (amphibians, sauropsids and mammals) we found that neoplasia and malignancy prevalence increases with adult weight (contrary to Petos Paradox) and somatic mutation rate, but decreases with gestation time. Evolution of cancer susceptibility appears to have undergone sudden shifts followed by stabilizing selection. Outliers for neoplasia prevalence include the common porpoise (<1.3%), the Rodrigues fruit bat (<1.6%) the black-footed penguin (<0.4%), ferrets (63%) and opossums (35%). Discovering why some species have particularly high or low levels of cancer may lead to a better understanding of cancer syndromes and novel strategies for the management and prevention of cancer. Statement of SignificanceEvolution has discovered mechanisms for suppressing cancer in a wide variety of species. By analyzing veterinary necropsy records we can identify species with exceptionally high or low cancer prevalence. Discovering the mechanisms of cancer susceptibility and resistance may help improve cancer prevention and explain cancer syndromes.

cancer biology↗

bioRxiv2022

AI-powered pan-species computational pathology: bridging clinic and wildlife care

Cancers occur across species. Understanding what is consistent and varies across species can provide new insights into cancer initiation and evolution, with significant implications for animal welfare and wildlife conservation. We built the pan-species cancer digital pathology atlas (PANCAD) and conducted the first pan-species study of computational comparative pathology using a supervised convolutional neural network algorithm trained on human samples. The artificial intelligence algorithm achieves high accuracy in measuring immune response through single-cell classification for two transmissible cancers (canine transmissible venereal tumour, 0.94; Tasmanian devil facial tumour disease, 0.88). Furthermore, in 18 other vertebrate species (mammalia=11, reptilia=4, aves=2, and amphibia=1), accuracy (0.57-0.94) was influenced by cell morphological similarity preserved across different taxonomic groups, tumour sites, and variations in the immune compartment. A new metric, named morphospace overlap, was developed to guide veterinary pathologists towards rational deployment of this technology on new samples. This study provides the foundation and guidelines for transferring artificial intelligence technologies to veterinary pathology based on a new understanding of morphological conservation, which could vastly accelerate new developments in veterinary medicine and comparative oncology.

cancer biology↗