Stimulus-induced gamma rhythms are weaker in human elderly with Mild Cognitive Impairment and Alzheimer's Disease
- Indian Institute of Science, India
- MS Ramaiah Medical College & Memorial Hospital, India
- National Institute of Mental Health and Neurosciences, India
Abstract
Alzheimer's Disease (AD) in elderly adds substantially to socio-economic burden necessitating early diagnosis. While recent studies in rodent models of AD have suggested diagnostic and therapeutic value for gamma rhythms in brain, the same has not been rigorously tested in humans. In this case-control study, we recruited a large population (N=244; 106 females) of elderly (>49 years) subjects from the community, who viewed large gratings that induced strong gamma oscillations in their electroencephalogram (EEG). These subjects were classified as healthy (N=227), mild-cognitively-impaired (MCI; N=12) or AD (N=5) based on clinical history and Clinical Dementia Rating scores. Surprisingly, stimulus-induced gamma rhythms, but not alpha or steady-state visually evoked responses, were significantly lower in MCI/AD subjects compared to their age and gender matched controls. This reduction was not due to differences in eye-movements or baseline power. Our results suggest that gamma could be used as potential screening tool for MCI/AD in humans.
Data availability
All spectral analyses were performed using Chronux toolbox (version 2.10), available at http://chronux.org. Relevant data and codes are available at the following GitHub repository: https://github.com/supratimray/TLSAEEGProjectPrograms.
Article and author information
Author details
Simran Purokayastha
Funding
Tata Trusts
- Naren Prahalada Rao
- Supratim Ray
Wellcome Trust/DBT India Alliance (Intermediate fellowship 500145/Z/09/Z)
- Supratim Ray
Wellcome Trust/DBT India Alliance (Senior fellowship IA/S/18/2/504003)
- Supratim Ray
Department of Biotechnology, Ministry of Science and Technology, India (DBT-IISc Partnership Programme)
- Supratim Ray
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: We obtained informed consent from all participants before the experiment. The Institute Human Ethics Committees of Indian Institute of Science (IHEC numbers: original: 22/2014, revised: 7-15092017), NIMHANS, and M S Ramaiah Hospital, Bangalore approved all procedures.
Copyright
© 2021, Murty et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Stimulus-induced gamma rhythms are weaker in human elderly with Mild Cognitive Impairment and Alzheimer's Disease
eLife 10:e61666.
https://doi.org/10.7554/eLife.61666
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