Biology subjects

Dreszer, J.

Publications and source records attributed to Dreszer, J..

3 recordsLinked to original sources

bioRxiv2025

Multi-Source Neural Activity Indices and Spatial Filters for EEG/MEG Inverse Problem: An Extension to MNE-Python

Accurate electroencephalography (EEG) and magnetoencephalography (MEG) source localization and reconstruction are essential for understanding brain function, yet remain challenging because the underlying EEG/MEG inverse problem is inherently ill-posed. Spatial filtering (beamforming) approaches, such as linearly constrained minimum variance (LCMV) spatial filters, are widely used and well supported by existing analysis software. In this work, we extend this framework by deriving a novel family of unbiased multi-source neural activity indices that form the localization stage of a two-stage spatial-filtering-based localization-reconstruction framework for the EEG/MEG inverse problem. In contrast to existing formulations, the proposed indices do not require knowledge of the target source covariance matrix, making them directly applicable in practical experimental settings. Their compact algebraic forms enable straightforward and numerically efficient implementation. The framework is validated on simulated EEG data and its applicability is illustrated through an example involving experimental EEG data from an oddball paradigm. To facilitate adoption, we provide a full open-source implementation extending MNE-Python, accompanied by a practical tutorial.

neuroscience↗

bioRxiv2024

Art's Hidden Topology: A window into human perception

Generations of researchers have sought a link between features of an artistic image and the audiences experience. However, a direct link between the properties of an image and the responses evoked has still not been established. Given the importance of shape to human perception and artistic creation, it can be assumed that one of the most important aspects of an artistic image is the use of different visual structures. We show that a method from the field of computational topology, persistent homology, can be used to analyse properties of image structures and composition at multiple scales. In order to determine the reliability of this method as a tool for analysing visual artworks, we analysed two different sets of abstract paintings that revealed significant discrepancies in the eye tracking and electroencephalography (EEG) activity of viewers. Our research showed that our newly developed method using persistent homology, not only clearly distinguished between two sets of images, which was not possible with common statistical image properties, but also allowed us to map topological features onto gaze fixation heat maps.

neuroscience↗

bioRxiv2024

Local variation in brain temperature explains gender-specificity of working memory performance

Exploring gender differences in cognitive abilities offers vital insights into human brain functioning. Our study utilized advanced techniques like magnetic resonance thermometry, standard working memory n-back tasks, and functional MRI to investigate if gender-based variations in brain temperature correlate with distinct neuronal responses and working memory capabilities. Interestingly, our findings revealed no gender disparity in working memory performance. However, we observed a significant decrease in average brain temperature in males during working memory tasks, a phenomenon not seen in females. Although changes in female brain temperature were not statistically significant, we found an inverse relationship between the absolute temperature change (ATC) and cognitive performance, alongside a correlation with blood oxygen level dependent (BOLD) neuronal responses. This suggests that in females, ATC is a crucial determinant for the link between cognitive performance and BOLD responses, a linkage not evident in males. Our results also suggest that females compensate for their brains heightened temperature sensitivity by activating additional neuronal networks to support working memory. This study not only underscores the complexity of gender differences in cognitive processing but also opens new avenues for understanding how temperature fluctuations influence brain functionality. SignificanceSex/gender differences in cognition are of high scientific and social interest. Yet, those differences (if any) remain elusive. Here we used magnetic resonance thermometry and functional MRI to examine, whether gender differences in working memory performance (WMP) are determined by subtle, yet detectable between-sex differences in local brain temperature fluctuations mediated by blood oxygen level-dependent (BOLD) neuronal responses. We found that WMP did not differ between genders. Yet, a females WMP was more sensitive to brain temperature variation compared to males. Furthermore, the negative impact of temperature on female cognitive functions was compensated by higher BOLD activity in other task-specific brain areas. This compensation may account for equivocal results of studies on the between-sex differences in cognitive performance.

neuroscience↗