On June 25-29, 2024, the forum organized by the Federation of European Neuroscience Societies (FENS) 2024 was held in Vienna (Austria).

FENS Forum is the largest international congress on neuroscience in Europe, covering all areas of neuroscience from fundamental to translational research.

On behalf of Skoltech, postgraduate students of the Center for Molecular and Cellular Biology Dmitry Kryukov and Ekaterina Kuzmina took part in the conference with the following works:

Nuclear expansion drives chromatin structure remodeling in aging neurons

Dmitrii Kriukov, Ekaterina Eremenko, Dmitrii Smirnov, Daniel Stein, Alexandra Tsitrina, Anastasia Golova, Monica Einav, Ekaterina Khrameeva, Debra Toiber

Aging, particularly in the brain, involves impairments in multiple cellular and molecular functions, many of which are regulated at the nucleus. Chromatin structure plays a critical role in the regulation of gene expression and the maintenance of genomic stability. During differentiation, chromosomes acquire their unique topology depending on the cell type that should be kept for a lifetime, but this may deteriorate as we age. However, the effects of aging on the chromatin 3D structure of neurons remain largely unknown and much has been inferred from senescent cells. By combining chromosome conformation capture and microscopy techniques, we investigated cortical neurons of young and aged mice and discovered neuronal nuclear expansion during neuronal aging, leading to increased distances between chromosomes. This expansion alters the topology of compartments, topologically associating domains (TADs) and chromatin loops. While larger TADs tend to dissociate, smaller TADs and loops exhibit strengthened interactions to maintain the cohesiveness of chromatin in aged neurons. These topological changes impact the borders of TADs, resulting in their overall weakening. Interestingly, we attribute these alterations to changes in the physical forces of an expanding nucleus, filling a growing nuclear area, affecting downstream gene expression and chromatin topology, further contributing to the functional declines observed during aging. 

Neuronal travelling waves explain rotational dynamics in experimental datasets and modelling

Ekaterina Kuzmina, Dmitrii Kriukov, Mikhail Lebedev

Spatiotemporal properties of neuronal population activity in cortical motor areas have been subjects of experimental and theoretical investigations, generating numerous interpretations regarding mechanisms for preparing and executing limb movements. Two competing models, representational and dynamical, strive to explain the relationship between movement parameters and neuronal activity. A dynamical model uses the jPCA method that holistically characterizes oscillatory activity in neuron populations by maximizing the data rotational dynamics. Different rotational dynamics interpretations revealed by the jPCA approach have been proposed. Yet, the nature of such dynamics remains poorly understood. We comprehensively analyzed several neuronal-population datasets and found rotational dynamics consistently accounted for by a traveling wave pattern. For quantifying rotation strength, we developed a complex-valued measure, the gyration number. Additionally, we identified parameters influencing rotation extent in the data. Our findings suggest that rotational dynamics and traveling waves are typically the same phenomena, so reevaluation of the previous interpretations where they were considered separate entities is needed.