Age-Related Changes in Functional Connectivity during the Sensorimotor Integration Detected by Artificial Neural Network

Abstract

Large-scale functional connectivity is an important indicator of the brain’s normal functioning. The abnormalities in the connectivity pattern can be used as a diagnostic tool to detect various neurological disorders. The present paper describes the functional connectivity assessment based on artificial intelligence to reveal age-related changes in neural response in a simple motor execution task. Twenty subjects of two age groups performed repetitive motor tasks on command, while the whole-scalp EEG was recorded. We applied the model based on the feed-forward multilayer perceptron to detect functional relationships between five groups of sensors located over the frontal, parietal, left, right, and middle motor cortex. Functional dependence was evaluated with the predicted and original time series coefficient of determination. Then, we applied statistical analysis to highlight the significant features of the functional connectivity network assessed by our model. Our findings revealed the connectivity pattern is consistent with modern ideas of the healthy aging effect on neural activation. Elderly adults demonstrate a pronounced activation of the whole-brain theta-band network and decreased activation of frontal–parietal and motor areas of the mu-band. Between-subject analysis revealed a strengthening of inter-areal task-relevant links in elderly adults. These findings can be interpreted as an increased cognitive demand in elderly adults to perform simple motor tasks with the dominant hand, induced by age-related working memory decline.

Aging alters the functional connectivity of motor theta networks during sensorimotor reactions

“…Moreover, although task complexity effect was more robust for the auditory than visual modality in the two age groups, the altered connectivity of the movement-generating M1 in aged subjects was not affected by this interaction. Together, these observations support and extend previous studies (Frolov et al 2020;Rosjat et al, 2021;Pitsik et al, 2022) by revealing that the detected effects of aging on contra-lateral M1 connections are stable, not being modulated by functional variables and task processing demands.…”

“…On the other hand, when processes of external sensory guidance or motor planning, initiation, and sensorimotor integration are considered, networks from slower frequency bands appear to be functionally reactive. Rosjat et al (2018Rosjat et al ( , 2021 have identified age differences for a lowfrequency (delta/theta) network characterized by reduced variability of the subnetworks, emergence of additional enhanced inter-hemispheric connections, and different activations of prefrontal and premotor areas (see Frolov et al, 2020, Pitsik et al, 2022 for similar results). These low-frequency networks appear of special interest also because response-related potentials (RRPs) generated after external sensory stimulation are composed of slower frequency components from delta/theta frequency bands in both young and old individuals (Popovych et al, 2016;Liu et al, 2017;Yordanova et al, 2004Yordanova et al, , 2020.…”

Perceptual Integration Compensates for Attention Deficit in Elderly during Repetitive Auditory-Based Sensorimotor Task

“…In this context, Dushanova and Christov [ 15 ] found the age-related distinctions in low-frequency EEG activity, which more likely indicate a decrease in memory operations during sensory processing in elderly adults. Our recent study identified an age-related deficit of working memory as a potential factor in the slowing of auditory-stimulated motor execution [ 16 , 18 ].…”