Concurrent Changes of Brain Functional Connectivity and Motor Variability When Adapting to Task Constraints

Abstract

In behavioral neuroscience, the adaptability of humans facing different constraints has been addressed on one side at the brain level, where a variety of functional networks dynamically support the same performance, and on the other side at the behavioral level, where fractal properties in sensorimotor variables have been considered as a hallmark of adaptability. To bridge the gap between the two levels of observation, we have jointly investigated the changes of network connectivity in the sensorimotor cortex assessed by modularity analysis and the properties of motor variability assessed by multifractal analysis during a prolonged tapping task. Four groups of participants had to produce the same tapping performance while being deprived from 0, 1, 2, or 3 sensory feedbacks simultaneously (auditory and/or visual and/or tactile). Whereas tapping performance was not statistically different across groups, the number of brain networks involved and the degree of multifractality of the inter-tap interval series were significantly correlated, increasing as a function of feedback deprivation. Our findings provide first evidence that concomitant changes in brain modularity and multifractal properties characterize adaptations underlying unchanged performance. We discuss implications of our findings with respect to the degeneracy properties of complex systems, and the entanglement of adaptability and effective adaptation.

A network information theoretic framework to characterise muscle synergies in space and time

“…In the context of the synergies extracted here and their reorganisation, fluctuations in these network properties from trial-to-trial may provide interesting insight into the neural control of movement. This is supported by experimental findings where increased integration in the muscle space and the reorganisation of modular structure from trial-to-trial were observed with additional motor noise and adaptations to task constraints respectively [46,47].…”

Fractal properties in sensorimotor variability unveil internal adaptations of the organism before symptomatic functional decline

“…In this line, multifractal fluctuations in movement variables were also shown to predict the integration and use of perceptual information to adapt motor behaviour to external perturbations 25 . More specifically, recent studies bridging behavioural and brain observation levels showed that the degree of multifractality in tapping relates to (re)organizations in functional brain connectivity underlying the tapping performance: an increase in the width of multifractal spectra of ITI series was shown to correlate with increased number of different brain networks involved in the task 54 . Shifts in brain connectivity were indeed evidenced as an adaptive response to feedback deprivation in the cases of chronic/pathological conditions as well as transient experimental manipulations, with notably an increased connectivity and diversification of neural circuits across sensory and non-sensory areas 49,50,55,56 .…”

Neurovascular Coupling by Functional Near Infra-Red Spectroscopy and Sport-Related Concussion in Retired Rugby Players: The UK Rugby Health Project

“…The fNIRS cranial headpiece was placed 1 cm above the eyebrow on the supraorbital ridge to avoid the sinuses. The 8-channel system (OctaMon, Artinis Medical, Netherlands) monitored changes in O 2 Hb and HHb in the pre-frontal cortex, specifically covering the dorsolateral (DLPFC) and orbitofrontal (OFC) cortices in both hemispheres (Vergotte et al, 2018). Our study performed a modified Neary Protocol (Neary et al, 2019) to assess NVC using the ''Where's Wally (Waldo)'' paradigm.…”