Biology subjects

Engeser, M.

Publications and source records attributed to Engeser, M..

4 recordsLinked to original sources

bioRxiv2026

Can Individual Internal Models Predict Idiosyncratic Scene Exploration?

Each individual person looks at natural scenes in their own unique way, resulting in a distinct perceptual experience of the world. However, little is known about why such differences in gaze emerge. Here, we test the hypothesis that idiosyncrasies in gaze behavior are predicted by inter-subject variations in internal models--expectations about how scenes typically look. In two experiments, we first characterized participants personal internal models by asking them to draw typical bathroom and kitchen scenes. Individual differences in these drawings were quantified using an objective deep learning pipeline and, in turn, related to individual differences in gaze behavior. In Experiment 1, where participants freely viewed a set of kitchen and bathroom photographs, inter-subject similarities in internal models did not predict inter-subject similarities in gaze. In Experiment 2, we encouraged strategic exploration through gaze-contingent viewing and a memory task. Here, inter-subject similarities in internal models predicted similarities in fixation frequency and the sequence in which different object categories were inspected. These findings suggest that the influence of internal models on visual exploration is stronger under increased sensory uncertainty and when expectation-guided sampling of the environment is encouraged. Together, our results provide new insights into how individual expectations shape gaze behavior and help explain why people differ in how they explore the visual world.

neuroscience↗

bioRxiv2026

Temporal Dynamics of EEG Decoding for Continuously Changing Visual Stimuli

Multivariate analyses of M/EEG data are typically performed on neural responses time-locked to discrete stimulus onsets. Such designs usually reveal high decoding performance during the initial transient response (0-500 ms), which subsequently drops to a lower, sustained level. Here, we examined time-resolved EEG decoding of natural scene processing when scenes gradually enter the visual field without a clear onset. We created video sequences in which one scene category (e.g., a beach) smoothly transitioned into another category (e.g., a forest) by blending images from two categories into a single composite panorama and moving a square aperture across it. We then compared EEG decoding for the first scenes within the transitions, which appeared with a sudden onset, to the second scenes, which emerged gradually as the videos progressed. For the first scenes, we observed robust category decoding from 60 ms after onset with a clear peak structure. For the second scene, category decoding was markedly weaker and showed no discernable peak structure. Realigning the appearance of category-diagnostic content for the second scene using deep neural networks did not enhance decoding or recover a peak structure. Further, classifiers trained on the first scene generalized to the second, but with a broad, temporally diffuse pattern, indicating that the second scene did not engage the same hierarchical temporal cascade as the first. Together, these results demonstrate that sudden versus gradual onsets produce distinct temporal decoding dynamics. Insights from onset-based decoding studies, therefore, do not straightforwardly extend to continuous and free-flowing natural stimulation.

neuroscience↗

bioRxiv2025

How do visual and conceptual factors predict the composition of typical scene drawings?

Imagine you are asked to draw a typical bedroom, what would you put on paper? Your choice of objects is likely to depend on visual occurrence statistics (i.e., the objects present in previously encountered bedrooms) and semantic relations between objects and scenes (i.e., the semantic relationship between the bedroom and its constituent objects). To investigate how these two factors contribute to the composition of typical scene drawings, we analyzed 1,192 drawings of six indoor scene categories, obtained from 303 participants. For each object featured in the drawings, we estimated its visual occurrence frequency from the ADE20K dataset of annotated scene images, and its semantic relatedness to the scene concept from a word2vec language processing model. Across all scenes of a given category, generalized linear models revealed that visual and conceptual factors both predicted the likelihood of an object featuring in the scene drawings, with a combined model outperforming both single-factor models. We further computed the visual and semantic specificity of objects for a given scene, that is, how diagnostic an object is for the scene. Object specificity offered only weak predictive power when predicting the selection of objects, yet even infrequently drawn objects remained diagnostic of their scenes. Taken together, we show that visual and conceptual factors jointly shape the composition of typical scene drawings. By releasing a large dataset of typical scene drawings alongside this work, we further provide a starting point for future studies exploring other critical properties of human drawings.

neuroscience↗

bioRxiv2024

The SAVED domain of the type III CRISPR protease CalpL is a ring nuclease

Prokaryotic CRISPR-Cas immune systems detect and cleave foreign nucleic acids. In type III CRISPR-Cas systems, the Cas10 subunit of the activated recognition complex synthesizes cyclic oligoadenylates (cOAs), second messengers that activate downstream ancillary effector proteins. Once the viral attack has been weathered, elimination of extant cOA is essential to limit the antiviral response and to allow cellular recovery. Various families of ring nucleases have been identified, specializing in the degradation of cOAs either as standalone enzymes or as domains of effector proteins. Here we describe the ring nuclease activity inherent in the SAVED domain of the cA4-activated CRISPR Lon protease CalpL. We characterize the kinetics of cA4 cleavage and identify key catalytic residues. We demonstrate that cA4-incuced oligomerization of CalpL is essential not only for activation of the protease, but is also required for nuclease activity. Further, the nuclease activity of CalpL poses a limitation to the protease reaction, indicating a mechanism for regulation of the CalpL/T/S signaling cascade. This work is the first demonstration of a catalytic SAVED domain and gives new insights into the dynamics of transcriptional adaption in CRISPR defense systems which are not aimed at abortive infection but rather at a reversible adaption to phage attack.

biochemistry↗