Biology subjects

Collin, S.

Publications and source records attributed to Collin, S..

9 recordsLinked to original sources

bioRxiv2026

Naturalistic narrative listening reveals a core brain network for detecting moral information

Moral cognition is a complex process, which recruits a wide range of mechanisms. It is not clear whether any of them reliably reflects moral content in the stimulus. We set out to test whether a specific mechanism of moral content representation and/or detection exists, and where it is, if it exists. To that end we used uni- and multi-variate analyses, including inter-subject pattern correlation, on functional MRI recordings of people listening to naturalistic narratives with moral content. We discovered a core brain network for detecting moral content, which prominently involves the TPJ, MTG/STG, among other regions. Moral content is reliably detected across narratives and participants, independent of instructions to do so, prominently involving the TPJ that functions as a detector. We identify specific regions for moral features, such as vices/virtues. Our methods and results open a path to further understand how the brain processes specific features of moral content.

neuroscience↗

bioRxiv2025

Distinct functional roles across hippocampal subfields in anticipation to event boundaries during schema learning

Continuous experiences are constantly segmented into separate events in memory, which is accompanied by increased hippocampal activity at the boundaries between these events. Extracting knowledge across all these experiences about what type of events to expect in a certain environment leads to event schemas being represented in the brain. These event schemas help to predict future events. What are the differences across the various distinct hippocampal subfields in peaks of activity around event boundaries? And what is the influence of event schema learning on these hippocampal subfield peaks? Here, this was investigated using data from an fMRI experiment in which participants learned two (related) event schemas by exposure to many similar animated videos of wedding ceremonies in a novel fictional culture. Results revealed that the hippocampus (CA1, CA2/3, dentate gyrus and subiculum) showed peaks in activity before event boundaries. Interestingly, the CA1, CA2/3 and dentate gyrus pre-boundary peaks attenuated due to event schema learning. This provides evidence for these subfields signaling uncertainty about upcoming events in the seconds prior to event boundaries. These results give a more precise understanding about the temporal dynamics around event boundaries in the distinct hippocampal subfields, and how these hippocampal subfields responses interact with schema learning.

neuroscience↗

bioRxiv2025

Subsequent memory effect in the inferior frontal gyrus revealed by fNIRS

A central finding in memory research is the subsequent memory effect, which describes consistent neural differences during encoding between events that are later remembered versus those that are forgotten, which has been reliably replicated with both EEG and fMRI for the past decades. Replicating the subsequent memory effect using fNIRS could enable research opportunities that are difficult to pursue with other methods, including studies with children, patient populations, or experiments in highly naturalistic settings. Therefore, our study investigated whether the prefrontal cortex is differentially involved in subsequently remembered versus subsequently forgotten stimuli using fNIRS. Our results showed that in particular channels mapping onto the inferior frontal gyrus showed more activation during encoding of subsequently remembered events compared to subsequently forgotten events. These results demonstrate that fNIRS can reliably capture the subsequent memory effect, providing new opportunities to study memory mechanisms across diverse populations and real-world contexts.

neuroscience↗

bioRxiv2025

From one schema to another: How the prefrontal cortex responds to conflicting information

Over time, we develop event schemas or scripts that shape our expectations about what typically happens in certain contexts. However, even after forming a memory about a certain event, we are often exposed to related information about that same event at later points in time. This additional information sometimes causes one to have to re-evaluate the interpretation of the original event. Over a two-day fNIRS experiment, participants were exposed to events that were subsequently updated with schema-congruent or schemaincongruent additional details. These schema-incongruent additional details make those events more fitting to another schema than originally was the case, meaning that participants would need to dissociate that event from the original schema and re-integrate it with another schema. The fNIRS results showed stronger PFC activity for events updated with schema-congruent compared to schema-incongruent details. When specifically looking at those events that were updated with schema-incongruent details, our results suggest that dissociating an event from the original schema and re-integrating it with another schema was accompanied by an initial PFC decrease early in the trial followed by a PFC increase later in the trial. This was a distinctly different pattern compared to trials in which participants failed to re-integrate the event with another schema, which showed delayed PFC increase with lower amplitude and no initial PFC decrease. Our results refine our understanding of mechanisms of adaptive memory updating in the face of conflicting information.

neuroscience↗

bioRxiv2024

Cross-task implications: How hippocampal event boundary responses predict unrelated memory performance

Hippocampal responses at event boundaries have been shown to predict memory performance for these events. However, are these hippocampal event boundary responses specific to memory for those particular events, or can they also have predictive power across various memory tasks? We used data from the Cam-CAN project (fMRI data from continuous movie viewing and memory results from an unrelated Famous Faces Task, N = 630) to determine whether hippocampal responses at event boundaries during the continuous movie viewing were indicative of memory performance in the unrelated Famous Faces task using various machine learning algorithms. The results showed that memory performance in the Famous Faces Task could be predicted based on participants hippocampal event boundary responses in another task, which suggests that the hippocampal event boundary responses are indicative for general memory performance. This might indicate importance of these hippocampal event boundary responses in terms of general information processing of the human brain.

neuroscience↗

bioRxiv2023

Deciphering lipid mutant phenotypes with a new genome-scale metabolic model of Microchloropsis gaditana encompassing detailed lipid metabolism

The oleaginous microalga Microchloropsis gaditana (formerly Nannochloropsis gaditana) has gained large interest due to its potential to produce lipids for a wide range of biotechnological applications. To optimize M. gaditana growth conditions and develop new strains to enhance lipid synthesis and accumulation, a broad understanding of the organism metabolism is essential. Computational models such as genome-scale metabolic models constitute powerful tools for unravelling microorganism metabolism. In this work we present iMgadit23, a new genome-scale metabolic model for M. gaditana. Model covers 2330 reactions involving 1977 metabolites and associated with 889 genes. Pathways involved in membrane and storage glycerolipid biosynthesis and degradation have undergone thorough manual curation and have been comprehensively described based on current knowledge of M. gaditana lipid metabolism. Additionally, we developed a detailed 2D-pathway map of model content to provide a systems-level visualization of M. gaditana metabolism. We demonstrated the predictive capabilities of iMgadit23, validating its ability to qualitatively and quantitatively capture in vivo growth phenotypes under diverse environmental and genetic conditions. Model was also able to capture the role of the Bubblegum acyl-CoA synthetase in remodeling M. gaditana lipid metabolism. iMgadit23 and its 2D map constitute valuable tools to increase understanding of M. gaditana metabolism and deciphering mutant phenotypes, specifically in the context of lipid metabolism. The model holds significant promise in predicting M. gaditana metabolic capabilities, facilitating strain engineering, and optimizing cultivation processes for a broad range of industrial applications.

plant biology↗

bioRxiv2023

A latent cardiomyocyte regeneration potential in the human heart

Cardiomyocytes in the adult human heart show a regenerative capacity, with an annual renewal rate around 0.5%. Whether this regenerative capacity of human cardiomyocytes is employed in heart failure has been controversial. Using retrospective 14C birth dating we analyzed cardiomyocyte renewal in patients with end-stage heart failure. We show that cardiomyocyte generation is minimal in end-stage heart failure patients at rates 18-50 times lower compared to the healthy heart. However, patients receiving left ventricle support device therapy, who showed significant functional and structural cardiac improvement, had a >6-fold increase in cardiomyocyte renewal relative to the healthy heart. Our findings reveal a substantial cardiomyocyte regeneration potential in human heart disease, which could be exploited therapeutically.

cell biology↗

bioRxiv2022

Membrane lipid adaptation of soil Gram-negative bacteria isolates to temperature and pH

3-hydroxy fatty acids (3-OH FAs) are characteristic components of the Gram-negative bacterial membrane, recently proposed as promising temperature and pH (paleo) proxies in soil. Nevertheless, to date, the relationships between the 3-OH FA distribution and temperature/pH are only based on empirical studies, with no work at the microbial level. This work investigated the influence of growth temperature and pH on the lipid profile in three strains of soil Gram-negative bacteria belonging to the Bacteroidetes phylum. Even though the non-hydroxy FAs were more abundant than the 3-OH FAs in the investigated strains, we showed the important role of the 3-OH FAs in the membrane adaptation of Gram-negative bacteria to temperature. The strains shared a common adaptation mechanism to temperature, with a significant increase in the ratio of anteiso vs. iso or normal 3-OH FAs at lower temperature. In contrast with temperature, no common adaptation mechanism to pH was noticed, the variations in the FA lipid profiles differing from one strain to another. The models envisioning the reconstruction of environmental changes in soils should include the whole suite of 3-OH FAs present in the membrane of Gram-negative bacteria, as all of them can be influenced by temperature or pH at the microbial level.

microbiology↗

bioRxiv2021

Hippocampal reconfiguration of events in mnemonic networks

It is widely assumed that episodic memories are not stored in isolation but rather in dynamic event networks. However, the mechanisms of the underlying dynamic of these representations, in particular how such networks are updated, remain elusive. In this study, we investigated the reconfiguration of events into event networks in the hippocampus by presenting new events that could update either one of two competing narratives. During the first session, participants viewed four animated movies, each representing a distinct narrative; two distinct narratives from the Jones family and two distinct narratives from the Smith family. During the second session, we re-exposed participants to snapshots of these narratives along with snapshots of new events from one of the two families, allowing updating of the acquired event networks of that family. Our findings show that the hippocampus integrated new events that relate to the old family, and then integrated these new events with the corresponding old events. Furthermore, hippocampal representations of the events within a narrative became better integrated after updating. Our results shed new light on the neural mechanisms underlying flexible mnemonic updating with realistic events and further advance our understanding of the structured reconfiguration of event networks in memory.

neuroscience↗