Reichelt, A. | Search bioRxiv

bioRxiv2025

Intrinsic electrophysiological activity maps a latent dimension of poor sleep quality and reduced cognitive performance: a magnetoencephalography study using Cam-CAN data.

Sleep quality and cognition vary as functions of lifestyle, genetics, and health. However, poor sleep quality is prevalent, reportedly affecting approximately 38% of the adult population. Poor sleep quality is a significant risk factor for mood disorders, a predictive factor in cognitive decline in later life, and sleep disturbance is a putative precursor to severe cognitive impairment and is predictive of dementia onset. The direct relationship between these factors and intrinsic neural function is poorly understood. Integrating neurophysiology, cognition, and sleep quality to reveal latent factors would help understand the neurophysiology of sleep disturbances and their relation to cognitive performance. Here, we used data from the Cam-CAN dataset with a partial least squares (PLS) approach, producing a multivariate cross-decomposition model to map resting-state magnetoencephalography (MEG) data and cognitive/sleep scores of healthy controls (n = 490, age 18-86). Normative modelling was applied to MEG data, correcting for effects of age, sex, and handedness. We identify a significant relationship between poorer self-reported sleep quality and lower cognitive performance across multiple domains, characterised by excess low-frequency neural activity and reduced high-frequency activity, particularly in the alpha band. Moreover, globally increased low frequency and decreased alpha-beta functional connectivity - the dominant frequency channel in neural connectivity at rest across the brain - contribute significantly to this relationship. Our multivariate mapping approach enabled us to parse the electrophysiological signatures directly related to sleep quality and cognitive performance, independent of the confounding effects of age, and show that neural slowing and dysconnectivity are intrinsically linked to self-reported sleep quality and cognitive performance.

neuroscience↗

bioRxiv2019

Distinct ROPGEFs successively drive polarization and outgrowth of root hairs

Root hairs are tubular protrusions of the root epidermis that significantly enlarge the exploitable soil volume in the rhizosphere. Trichoblasts, the cell type responsible for root hair formation, switch from cell elongation to tip growth through polarization of the growth machinery to a pre-defined root hair initiation domain (RHID) at the plasma membrane. The emergence of this polar domain resembles the establishment of cell polarity in other eukaryotic systems [1-3]. Rho-type GTPases of plants (ROPs) are among the first molecular determinants of the RHID [4, 5] and later play a central role in polar growth [6]. Numerous studies have elucidated mechanisms that position the RHID in the cell [7-9] or regulate ROP activity [10-18]. The molecular players that target ROPs to the RHID and initiate outgrowth, however, have not been identified. We dissected the timing of the growth machinery assembly in polarizing hair cells and found that positioning of molecular players and outgrowth are temporally separate processes that are each controlled by specific ROP guanine nucleotide exchange factor (GEFs). A functional analysis of trichoblast-specific GEFs revealed GEF3 to be required for normal ROP polarization and thus efficient root hair emergence, while GEF4 predominantly regulates subsequent tip growth. Ectopic expression of GEF3 induced the formation of spatially confined, ROP-recruiting domains in other cell types, demonstrating the role of GEF3 to serve as a membrane landmark during cell polarization. Our findings suggest that morphogenetic programs in plants employ distinct regulatory modules for the alignment and activation of the cellular growth machinery.

cell biology↗