Biology subjects

Frangou, P.

Publications and source records attributed to Frangou, P..

3 recordsLinked to original sources

bioRxiv2026

Effects of cholinergic potentiation on resting-state functional connectivity in healthy adults

Acetylcholine is a key attentional neuromodulator, yet its effects on large-scale organisation of resting-state networks remain poorly understood. Here, we investigated whether acute cholinergic potentiation with the acetylcholinesterase inhibitor donepezil modulates functional connectivity within and between resting-state networks involved in attention. Nineteen healthy young adults completed a double-blind, placebo-controlled crossover study using 7T resting-state functional MRI (rs-fMRI), with imaging performed before and after administration of donepezil or placebo. We tested whether donepezil altered functional connectivity within and between the dorsal attention, ventral attention, default mode, and frontoparietal networks and whether it improved attentional orienting in the same volunteers. Voxel-wise analysis revealed a significant donepezil-related increase in dorsal attention network connectivity within the left inferior parietal cortex. We did not observe donepezil-related changes within the ventral attention, default mode, or frontoparietal networks. Network-level analyses did not identify significant global changes in network strength. Exploratory analyses indicated reduced coupling between the dorsal attention and default mode networks following donepezil relative to placebo, although this result did not survive correction for multiple comparisons. Donepezil did not significantly improve attentional orienting at the group level. However, exploratory analyses suggested that greater donepezil-related enhancement of functional connectivity within the identified left inferior parietal cluster was associated with greater improvement in attentional orienting. These findings suggest that acute cholinergic potentiation does not globally enhance resting-state connectivity across attentional networks in healthy young adults. Instead, donepezil may selectively modulate localised dorsal attention network circuitry, particularly within left inferior parietal cortex, a region implicated in sensory integration and externally oriented cognition.

neuroscience↗

bioRxiv2026

Development and Validation of the Transcranial Magnetic Stimulation Reporting Assessment Tool(TMS-RAT)

HighlightsO_LIWe introduce the TMS-RAT, a reporting (assessment) tool for TMS studies C_LIO_LIDeveloped within a community-informed, iterative process rating 333 TMS studies C_LIO_LIEmpirically evaluated for usability, inter-rater, and test-retest reliability C_LIO_LIA validated subset enables reliable retrospective assessment of reporting C_LIO_LIThe modular structure enables use across a wide range of TMS study designs C_LI BackgroundA standardised tool for comprehensive reporting can improve transparency, support consistent documentation, and enable comparison across transcranial magnetic stimulation (TMS) studies. The most used reporting checklist lacks clear definitions of full reporting and was not initially evaluated for usability or inter-rater reliability. A scoping review of studies using this checklist shows that its items are reported only 50% of the time, suggesting that method descriptions are often incomplete. MethodsWe developed the TMS Reporting Assessment Tool (TMS-RAT), a comprehensive reporting framework that provides clear definitions and examples for its items, covering a wide range of TMS protocols. We tested the usability and reliability of the TMS-RAT by rating all studies published between 1991 and 2025 using afferent conditioning (n = 333), a protocol encompassing many reporting categories identified during tool development. Seventeen independent raters contributed across three development phases, a validation phase, and a retest phase, with naive raters introduced in each phase. Iterative refinements of the tool were informed by inter-rater reliability, qualitative rater feedback, and consultation with external TMS experts. ResultsWe present two versions of the tool: the 72-item TMS-RAT v1.0, designed to guide comprehensive reporting, and the TMS-RAT v1.1, a subset of 50 items with the highest inter-rater (overall AC1 = 0.78, range = [0.60-0.99]) and test-retest reliability (overall AC1 = 0.82, range = [0.65-1.0]), intended for retrospective evaluation of reporting in systematic reviews, meta-analyses. ConclusionThe TMS-RAT is a comprehensive, reliable tool that seeks to improve transparency and reproducibility in TMS research.

neuroscience↗

bioRxiv2021

Brain stimulation boosts perceptual learning by altering sensory GABAergic plasticity and functional connectivity

Interpreting cluttered scenes --a key skill for successfully interacting with our environment-- relies on our ability to select relevant sensory signals while filtering out noise. Training is known to improve our ability to make these perceptual judgements by altering local processing in sensory brain areas. Yet, the brain-wide network mechanisms that mediate our ability for perceptual learning remain largely unknown. Here, we combine transcranial direct current stimulation (tDCS) with multi-modal brain measures to modulate cortical excitability during training on a signal-in-noise task (i.e. detection of visual patterns in noise) and test directly the link between processing in visual cortex and its interactions with decision-related areas (i.e. posterior parietal cortex). We test whether brain stimulation alters inhibitory processing in visual cortex, as measured by magnetic resonance spectroscopy (MRS) of GABA and functional connectivity between visual and posterior parietal cortex, as measured by resting state functional magnetic resonance imaging (rs-fMRI). We show that anodal tDCS during training results in faster learning and decreased GABA+ during training, before these changes occur for training without stimulation (i.e. sham). Further, anodal tDCS decreases occipito-parietal interactions and time-varying connectivity across the visual cortex. Our findings demonstrate that tDCS boosts learning by accelerating visual GABAergic plasticity and altering interactions between visual and decision-related areas, suggesting that training optimises gain control mechanisms (i.e. GABAergic inhibition) and functional inter-areal interactions to support perceptual learning.

neuroscience↗