Biology subjects

White, D. J.

Publications and source records attributed to White, D. J..

5 recordsLinked to original sources

bioRxiv2025

Examining excitation-inhibition modulation during social processing using functional Magnetic Resonance Spectroscopy

An imbalance of brain excitation-inhibition has been implicated in social communication function across neurodevelopmental and psychiatric conditions. Recent advances in functional magnetic resonance spectroscopy (fMRS) allow non-invasive measurement of dynamic changes in excitation-inhibition neurometabolites (glutamate and GABA), revealing potential links with cognitive processes. This study used functional MRS (fMRS) to investigate whether socially-laden stimuli modulate excitatory or inhibitory neurometabolites, and whether modulation relates to social function. Forty neurotypical adults (18-40 years; 20 male) underwent 3T MRI, with fMRS data acquired using a J-difference edited MRS sequence. GABA+macromolecules (GABA+) and glutamate+glutamine (Glx) were quantified in a right social brain region (superior temporal/temporoparietal junction [STG/TPJ]) and a control region (occipital cortex). Participants viewed a fixation cross (traditional resting state MRS; 5 min), silent video clips of social interaction, and a flashing checkerboard as control stimulus (5 min each; counterbalanced). The Social Responsiveness Scale (SRS-2) assessed social function. Block analysis showed no significant differences between resting and functional (social or checkerboard) GABA+ or Glx levels (ps<.05), although Bayesian analyses showed evidence for decreased STG/TPJ GABA+ and increased occipital cortex Glx for checkerboard compared to rest. Higher SRS-2 scores were associated with higher resting STG/TPJ Glx but not GABA+, and functional metabolite levels were not associated with SRS-2 scores (ps>.1). Sliding time- window analyses showed significantly reduced Glx in social brain during social stimulation. Despite sound data collection and analysis techniques, shifts in Glx and GABA+ following social stimuli were minimal. Future research could utilise more challenging social stimuli and examine alternate social brain regions.

neuroscience↗

bioRxiv2023

GABA and Glutamate response to social processing; a functional MRS study

Several studies have suggested that atypical social processing in multiple psychiatric conditions (e.g., autism) is associated with differences in excitation and inhibition, through changes in the levels of glutamate and GABA levels. While associations between baseline metabolite levels and behaviours can be insightful, assessing the neurometabolic response of GABA and Glutamate during social processing may inform altered neurochemical function in more depth. Thus far, there have been no attempts to determine whether changes in metabolite levels are detectable using functional magnetic resonance spectroscopy (fMRS) during social processing in a control population. We performed MEGA-PRESS edited fMRS to measure the dynamic response of GABA and glutamate in the superior temporal sulcus (STS) and visual cortex (V1) while viewing social stimuli, using a design that allows for analysis in both block and event-related approaches. Sliding window analyses were used to investigate GABA and glutamate dynamics at higher temporal resolution. A small decrease in GABA levels was observed during social stimulus presentation in V1, but no change was observed in STS. Conversely, non-social stimulus elicited changes in both GABA and glutamate levels in both regions. We discuss the feasibility of using fMRS analysis approaches to assess changes in metabolite response during social processing.

neuroscience↗

bioRxiv2022

Neurodesk: An accessible, flexible, and portable data analysis environment for reproducible neuroimaging

Neuroimaging data analysis often requires purpose-built software, which can be challenging to install and may produce different results across computing environments. Beyond being a roadblock to neuroscientists, these issues of accessibility and portability can hamper the reproducibility of neuroimaging data analysis pipelines. Here, we introduce the Neurodesk platform, which harnesses software containers to support a comprehensive and growing suite of neuroimaging software (https://www.neurodesk.org/). Neurodesk includes a browser-accessible virtual desktop environment and a command line interface, mediating access to containerized neuroimaging software libraries on various computing platforms, including personal and high-performance computers, cloud computing and Jupyter Notebooks. This community-oriented, open-source platform enables a paradigm shift for neuroimaging data analysis, allowing for accessible, flexible, fully reproducible, and portable data analysis pipelines.

neuroscience↗

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↗