Global scale-free brain activity as a potential neural signature of visual information processing in aging
Frigyes Samuel Racz1,2,3, Zalan Kaposzta3,4,5, Akos Czoch3
1Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, United States.
Introduction:
Confluent evidence suggests that aging is associated with a reduction in the spectral slope of neural recordings. This phenomenon has been hypothesized to reflect an increase in the ratio of excitatory and inhibitory (E/I) balance. As neural E/I ratio is considered essential for cognitive functioning, this study investigated whether spectral slope (β) predicts cognitive performance in the older adults and could serve as a potential neural signature of cognitive aging. Nevertheless, few studies have examined how spectral slope estimates obtained from both eyes-closed (EC) and eyes-open (EO) resting states relate to cognitive performance in the aging population.
Methods:
To address this gap, this study analyzed electroencephalography (EEG) recordings of 19 community-dwelling elderly adults (CDE, aged between 60 to 80 years) and 24 young control individuals (YC, aged between 21 to 32 years) collected during EC and EO states. Further, β was estimated from global power spectra after separating scale-free from oscillatory components in the power spectrum.
Results:
Reduced β was observed in CDE in contrast to YC in both physiological states. While the YC group indicated an increase in β when transitioning from EC to EO, this change could not be observed in CDE. Finally, a strong, anticorrelated relationship between β in EO and performance on a rapid visual information processing task, was typically seen only in the CDE group.
Discussion:
These results potentially indicate an altered E/I ratio in the CDE cohort, while the inverse relationship with task performance suggests that this pattern could reflect a compensatory brain mechanism supporting cognition during aging.
