Biology subjects

Scholey, A.

Publications and source records attributed to Scholey, A..

2 recordsLinked to original sources

bioRxiv2019

Resting state fMRI reveals differential effects of glucose administration on central appetite signalling in young and old adults

BackgroundHealthy aging has been associated with reduced appetite and energy intake, which can lead to loss of bodyweight and undernutrition and related health problems. The causes for the decline in caloric intake are multifactorial involving physiological and non-physiological processes. AimsHere we examined age-related, physiological changes in brain responses associated with macronutrient intake. MethodsUsing a randomized, double blind, balanced cross-over design, younger (n=16, aged 21-30) and older adults (n=16, aged 55-78) received a drink containing glucose and a taste-matched placebo after an overnight fast. Blood glucose and hunger were assessed at baseline and 20 minutes post-ingestion, after which participants underwent resting state functional magnetic resonance imaging (rsfMRI). ResultsFrequency dependent changes in slow-5 (0.01-0.027Hz) and slow-4 (0.027-0.073Hz) amplitude of low frequency fluctuations (ALFF) and fractional ALFF (fALFF) of the blood oxygen level-dependent (BOLD) signal were contrasted between sessions and age groups. We observed a significant treatment x age-group interaction in slow-5 ALFF and fALFF in the left insula. Younger participants showed a decrease in BOLD amplitude, whereas older participants showed an increase. We further observed a treatment x age-group interaction in slow-4 ALFF in the occipital and lingual gyrus and precuneus with older participants showing an increase in magnitude of slow-4 ALFF and younger participants showing a decrease in the same measure. ConclusionThese age-related, frequency-dependent changes in the magnitude of the BOLD signal in a key region related to energy homeostasis following feeding may contribute to behavioral changes in energy intake during senescence.

neuroscience↗

bioRxiv2018

Functional connectivity of the anterior and posterior hippocampus: differential effects of glucose in younger and older adults

AbstractThe hippocampus features structurally and functionally distinct anterior and posterior segments. Relatively few studies have examined how these change during aging or in response to pharmacological interventions. Alterations in hippocampal connectivity and changes in glucose regulation have each been associated with cognitive decline in aging. A distinct line of research suggests that administration of glucose can lead to a transient improvement in hippocampus-dependent memory.\n\nHere we probe age, glucose and human cognition with a special emphasis on resting state functional connectivity (rsFC) of the hippocampus along its longitudinal axis to the rest of the brain. Using a randomized, placebo-controlled, double-blind, crossover design thirty-two healthy adults (16 young and 16 older) ingested a drink containing 25g glucose or placebo across two counterbalanced sessions. They then underwent resting state functional magnetic resonance imaging and cognitive testing. There was a clear dissociation in the effects of glucose by age. In older participants rsFC between posterior hippocampus (pHPC) and medial prefrontal cortex (mPFC) increased after glucose ingestion, whereas in younger participants connectivity decreased. Magnitude change in rsFC from pHPC to mPFC was correlated with individual glucose regulation and gains in performance on a spatial navigation task. Our results demonstrate that glucose administration can attenuate cognitive performance deficits in older adults with impaired glucose regulation and suggest that increases in pHPC-mPFC rsFC are beneficial for navigation task performance in older participants. This study is the first to demonstrate the selective modulation of pHPC connectivity in the acute setting.

neuroscience↗