Biology subjects

Major, G.

Publications and source records attributed to Major, G..

4 recordsLinked to original sources

bioRxiv2026

Advanced meditation stabilizes cortical dynamics through inhibitory gain control linked to absorptive depth

Advanced meditation can shift conscious experience from ordinary body- and world-centered awareness toward absorption, detachment and dissociation-like states, yet the neural mechanisms that stabilize these immersive states remain unclear. We studied 18 long-term meditators during eyes-open rest and Rajyoga meditation, a practice in which practitioners reduce bodily identification while enhancing inner self-awareness. We combined multidimensional neural approach including frontal EEG spectral power, temporal non-stationarity and corticothalamic neural-field modeling, because these measures probe underlying complementary levels of the brain state transition: the strength of neural activity, its temporal stability, and the circuit level inhibition-excitation gain mechanisms. This framework is especially relevant to meditation because oscillatory, temporal organization may distinguish stable meditative states, and corticothalamic dynamics are closely linked to arousal and conscious state regulation. We correlated meditation induced neural changes with subjective ratings of absorption and dissociation. Compared with rest, meditation was associated with higher beta1, beta2 and gamma power, with no change in the slower bands (delta, theta and alpha), and with lower beta-band temporal non-stationarity, indicating a more stable expression of fast cortical dynamics. Fitting the corticothalamic model to the EEG spectra showed stronger cortical inhibitory gain and lower effective intracortical gain, placing meditation in an inhibition-dominant regime, with lower gain in the loop between excitatory and inhibitory neurons within the cortex. During meditation, these model estimates were related to subjective absorption and showed trend level links with dissociation. Together, these findings suggest that Rajyoga meditation stabilizes cortical dynamics through inhibitory gain control, linking absorption (deep and steady attention on the meditation) to dissociation-like self-detachment.

neuroscience↗

bioRxiv2026

ADSS1 is a suppressed metabolic control node in dystrophic skeletal muscle

Duchenne muscular dystrophy is initiated by dystrophin loss but is accompanied by profound metabolic remodelling. Here, we identify suppression of the muscle-enriched adenylosuccinate synthase, ADSS1, and the purine nucleotide cycle in mdx muscle. Integrated multi-omic profiling revealed a compensated purine-stress state in which nucleotide salvage and quality control were increased to preserve adenine nucleotide abundance and buffer consequential toxic/disruptive deoxy-/nucleotide production. Purine metabolism was the highest-impact joint pathway with metabolite and transcript hits in mdx muscle, and its maintenance program was directionally conserved in human ADSS1 myopathy. Interventions positioned around ADSS1 separated the outputs of this node. Ribose and dimethyl fumarate remodelled upstream or downstream stress programs, whereas only adenylosuccinic acid bypassed ADSS1 to expand the adenine nucleotide pool and remodel CoA/acetyl-CoA metabolism. All three interventions suppressed pro-adipogenic transcription without broadly correcting the lipidome. These findings identify ADSS1 as a regulated metabolic control node that couples purine retention to inflammatory and adipogenic remodelling in dystrophic muscle.

molecular biology↗

bioRxiv2024

Novel quantal analysis method reveals conservation of injected charge by excitatory synapses across cortical cells of different sizes

In chemical synapses of the central nervous system (CNS), information is transmitted via the presynaptic release of a vesicle (or quantum) of neurotransmitter, which elicits a postsynaptic electrical response with an amplitude termed the quantal size. Measuring amplitudes of miniature postsynaptic currents (mPSCs) or potentials (mPSPs) at the cell soma is generally thought to offer a technically straightforward way to estimate quantal sizes, as each of these miniature responses (or minis) is generally thought to be elicited by the spontaneous release of a single neurotransmitter vesicle. However, in large highly-branched neurons, a somatically recorded mini is typically massively attenuated compared with at its input site, and a significant fraction are indistinguishable from (or cancelled out by) background noise fluctuations. Here, using a new software package (also) called minis, we describe a novel quantal analysis method that estimates the electrical size of the synapse by comparing events detected in somatic recordings from the same neuron of (a) real minis and (b) background noise (with minis blocked pharmacologically) with simulated minis added by a genetic algorithm. The estimated minis distributions reveal a striking inverse dependence of mean excitatory mPSP amplitude on total cell membrane capacitance (proportional to cell size, or more exactly, extracellular membrane surface area) suggesting that, in rats at least, the average charge injected by single excitatory synapses (ca. 30 fC) is conserved across neocortical pyramidal neurons of very different sizes (across a more than three-fold range).

neuroscience↗

bioRxiv2022

Novel method for reliably measuring spontaneous postsynaptic potentials/currents in whole-cell patch clamp recordings in the central nervous system

Measurements of miniature postsynaptic currents (mPSCs) or potentials (mPSPs) in the soma of neurons of the central nervous system (CNS) provide a way of quantifying the synaptic function at the network level and, therefore, are routine in the neurophysiology literature. These miniature responses (or minis) are thought to be elicited by the spontaneous release of a single neurotransmitter vesicle, also called quantum. As such their measurement at the soma can potentially offer a technically straightforward way of estimating quantal sizes of central synapses. However, popular methods for detecting minis in whole-cell recordings fall short of being able to reliably distinguish them from background physiological noise. This issue has received very limited attention in the literature and its scope as well as the relative performance of existing algorithms have not been quantified. As a result, solutions for reliably measuring the quantal size in somatic recordings also do not exist. As the first step in proposing and testing a potential solution, we developed and described a novel mPSP/mPSC detection algorithm as part of our quantal analysis software called minis. We tested its performance in detecting real and simulated minis in whole-cell recordings from pyramidal neurons in rat neocortical slices and compared it to two of the most-used mini detection algorithms. This benchmarking revealed superior detection by our algorithm. The release version of the algorithm also offers great flexibility via graphical and programming interfaces.

neuroscience↗