Biology subjects

Simola, J.

Publications and source records attributed to Simola, J..

3 recordsLinked to original sources

bioRxiv2025

Neuronal oscillations predict un-cued task switching in the Wisconsin card sorting test

Cognitive flexibility is the ability to keep or update contextual cognitive representations. The underlying neural mechanisms and how it is influenced by individual sensitivity to feedback are not known. We measured cognitive flexibility under uncertainty with the Wisconsin Card Sorting Task and brain activity with magnetoencephalography (MEG). Using a behavioral sequential learning model, we show that variability in cognitive flexibility is predicted by individual reward and punishment sensitivity to feedback and anticipation and exploration tendencies. Uncovering their brain oscillatory signatures showed that individual learning speed is predicted by suppressed alpha-beta (7-32 Hz) and increased broad-band gamma (52-96 Hz) amplitudes along with concurrent large-scale alpha (7-13 Hz) desynchronization. Importantly, these oscillatory sub-processes were explained by individual levels of distinct feedback sensitivities. These results provide a novel account on neural sub-computations underlying flexible contextual switching between stable and unstable cognitive representations that predict the individual speed of rule learning.

neuroscience↗

bioRxiv2022

Is mild ADHD beneficial: Brain criticality is maximal with moderate ADHD symptom scores

Attention-deficit/hyperactivity disorder (ADHD) is characterized by a continuum of symptoms including inattentiveness, hyperfocus, and hyperactivity, that are manifested, e.g., in increased reaction-time variability in continuous performance tasks (CPTs). Framework of brain criticality posits that brains operate in an extended regime of critical-like dynamics where neuronal and behavioral processes exhibit scale-free long-range temporal correlations (LRTCs) across hundreds of seconds. Whether shifts across critical-like brain states and parallel changes in LRTCs underlie ADHD symptoms has remained unexplored. We investigated whether brain-state shifts towards excitation-dominated dynamics and associated changes in LRTCs could explain ADHD symptoms and their continuum across individuals. We measured brain activity with magnetoencephalography (MEG) during resting and two CPTs from adult participants diagnosed with ADHD (N = 34) and neurotypical controls (NC) (N = 36) and characterized criticality with LRTCs of neuronal oscillations. ADHD patients exhibited stronger LRTCs than NC in low (5-20 Hz) and high (30-100 Hz) frequencies and dichotomous task effects. High-frequency LRTCs were positively correlated with ADHD symptoms, while beta-band (20-30 Hz) activity exhibited a quadratic correlation, peaking at moderate scores across the ADHD and NC cohorts being smaller for low and high scores. We demonstrate that ADHD is associated with shifts in brain criticality in resting-and task-state brain dynamics. Individuals with intermediate symptom scores across the NC and ADHD cohorts operated at peak criticality that is associated with a several functional benefits The progressive shift towards the supercritical side of the critical regime becomes detrimental only at moderate and severe symptoms.

neuroscience↗

bioRxiv2021

Genetic polymorphisms in COMT and BDNF influence synchronization dynamics of human neuronal oscillations

Neuronal oscillations, their inter-areal synchronization, and scale-free dynamics constitute fundamental mechanisms for cognition by regulating communication in neuronal networks. These oscillatory dynamics have large inter-individual variability that is partly heritable. However, the genetic underpinnings of oscillatory dynamics have remained poorly understood. We recorded resting-state magnetoencephalography (MEG) from 82 healthy participants and investigated whether oscillation dynamics were influenced by genetic polymorphisms in Catechol-O-methyltransferase (COMT) Val158Met and brain-derived neurotrophic factor (BDNF) Val66Met. Both COMT and BDNF polymorphisms influenced local oscillation amplitudes and their long-range temporal correlations (LRTCs), while only BDNF polymorphism affected the strength of large-scale synchronization. Our findings demonstrate that COMT and BDNF genetic polymorphisms contribute to inter-individual variability in local and large-scale synchronization dynamics of neuronal oscillations. Comparison of these results to computational modelling of near-critical synchronization dynamics further suggested that COMT and BDNF polymorphisms influenced local oscillations by modulating the excitation-inhibition balance according to the brain criticality framework.

neuroscience↗