Biology subjects

Wilding, M.

Publications and source records attributed to Wilding, M..

4 recordsLinked to original sources

bioRxiv2024

Live imaging human embryos reveals mitotic errors and lineage specification prior to implantation

Meiotic and mitotic chromosome segregation errors in human development have been studied mostly prior to and at the time of fertilisation. Despite chromosomal errors being a leading cause of miscarriage and infertility, chromosome missegregation has not been extensively studied at later stages of human development. Here we optimised labelling, light-sheet live imaging and semi-quantitative analysis of human embryos and reveal chromosome segregation errors just prior to implantation. We found that human embryos exhibited a number of chromosome missegregation events including multipolar spindle formation, lagging chromosomes, misalignment and chromosome slippage. We found that the majority of lagging chromosomes were passively inherited by one of the daughter cells, instead of reincorporating into the nuclei, suggesting a distinct pattern of micronuclei inheritance. By semi-automated segmentation, we tracked the position of labelled cells in human embryos and observed that while most labelled cells remained segregated to the outside, and therefore restricted to a placental-progenitor fate, there was evidence of a rare cell migration to cells positioned on the inside, which suggests that there may be plasticity. Altogether, we found that mitotic chromosome segregation errors arise just prior to implantation, which has implications for our understanding of biological events that contribute to aneuploidy mosaicism.

developmental biology↗

bioRxiv2022

Resting-state functional connectivity predictors of subjective visual Gestalt experience

Subjective perceptual experience is influenced not only by bottom-up sensory information and experience-based top-down processes, but also by an individuals current brain state. Specifically, a previous study found increased prestimulus insula and intraparietal sulcus (IPS) activity before participants perceived an illusory Gestalt (global) compared to the non-illusory (local) interpretation in a bistable stimulus. This study provided only a snapshot of the prestimulus brain state that favors an illusory interpretation. In the current study, we tested the hypothesis that the neural machinery that biases perception towards the illusory interpretation immediately before the stimulus onset, is also predictive of an individuals general tendency to perceive it, which remains stable over time. We examined individual differences in task-free functional connectivity of insula and IPS and related it to differences in the individuals duration of the two interpretations. We found stronger connectivity of the IPS with areas of the default mode and visual networks to predict shorter local perceptual phases, i.e., a faster switch to an illusory percept, but no equivalent results for the insula. Our findings suggest a crucial role of an IPS interaction with nodes of key intrinsic networks in forming a perceptual tendency towards illusory Gestalt perception.

neuroscience↗

bioRxiv2022

Increased insula activity precedes the formation of subjective Gestalt

The constructive nature of human perception sometimes leads us to perceiving rather complex impressions from simple sensory input. Bistable stimuli give us a rare opportunity to study the neural mechanisms behind this process. Such stimuli can be visually interpreted as simple or as more complex on the basis of the same sensory input. Previous studies demonstrated increased activity in the superior parietal cortex when participants perceived an illusory Gestalt impression compared to a simpler interpretation of individual elements. Here we tested whether activity related to the illusory Gestalt can be detected not only during, but also prior to it, by examining the slow fluctuations of resting-state-fMRI activity before the stimulus onset. We presented 31 participants with a bistable motion stimulus, which can be perceived either as four moving dot pairs (local) or two moving illusory squares (global). This allowed us to isolate the specific neural mechanisms that accompany the experience of an illusion under matched sensory input. fMRI was used to measure brain activity in a sparse event-related design. We observed stronger IPS and putamen responses to the stimulus when participants perceived the global interpretation compared to local, confirming the previously reported role of these areas in perceptual grouping. Most importantly, we also observed that the global stimulus interpretation was preceded by an increased activity of the bilateral dorsal insula, which is known to process saliency and gate information for conscious access. Our data suggest an important role of the dorsal insula in shaping an internally generated illusory Gestalt percept.

neuroscience↗

bioRxiv2020

Methane emission of humans is explained by dietary habits, host genetics, local formate availability and a uniform archaeome

Archaea are responsible for methane production in the human gastrointestinal tract. Twenty percent of the Western populations exhale substantial amounts of this gas. The underlying principle determining high or low methane emission and its effect on human health was still not sufficiently understood. In this study, we analysed the gastrointestinal microbiome, archaeome, metagenome, metabolome, and eating behaviour of 100 healthy young adults. We correlated high levels of human methane emission (5-75 ppm) with a 1000-fold increase in Methanobrevibacter smithii. This archaeon co-occurred with a bacterial community specialised on dietary fibre degradation, which included members of the Ruminococcaceae and Christensenellaceae. Methane production was negatively affected by high vitamin B12 and fat intake of the subjects, and was positively associated with increased formate concentrations in the gut. Overall, methane emission is explained by dietary habits, host genetics, local metabolite availability and microbiome/archaeome composition, emphasizing the unique biology of high methane-emitters which has potentially positive impact on human health. O_FIG O_LINKSMALLFIG WIDTH=171 HEIGHT=200 SRC="FIGDIR/small/423794v1_ufig1.gif" ALT="Figure 1"> View larger version (79K): org.highwire.dtl.DTLVardef@16eb91org.highwire.dtl.DTLVardef@c3b928org.highwire.dtl.DTLVardef@1b11fa5org.highwire.dtl.DTLVardef@194bed2_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract:C_FLOATNO C_FIG

microbiology↗