bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/864496

Regional glia-related metabolite levels are higher at older age and scale negatively with visuo-spatial working memory: A cross-sectional proton MR spectroscopy study at 7 tesla on normal cognitive ageing

Lind, A.·Boraxbekk, C.-J.·Petersen, E. T.·Paulson, O. B.·Siebner, H.·Marsman, A.
View original source ↗Export metadata ↓

Abstract

Proton MR spectroscopy (1H-MRS) has been used to assess regional neurochemical brain changes during normal ageing, but results have varied. Exploiting the increased sensitivity at ultra-high field strength, we performed 1H-MRS in 60 healthy volunteers to asses age-related differences in neuron- and glia-related metabolite levels and their relation to cognitive ageing. Gender was balanced and participants were assigned to a younger, middle and older group according to their age, ranging from 18 to 79 years. They underwent 1H-MRS of anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), hippocampus and thalamus and performed a visuo-spatial working memory task outside the scanner. Multivariate ANCOVA revealed a significant overall effect of age group on metabolite levels in all brain regions of interest. Considering specific metabolites, elevated levels of glia-related metabolites in older age groups were observed in all brain regions. For the neuron-related metabolites, differences among age groups were only observed in two regions. We found higher levels of total N-acetyl aspartate in hippocampus for the older than the middle group, and lower levels of glutamate in DLPFC in the older than the younger group. Working memory performance correlated negatively with levels of glia-related metabolites for total creatine and total choline in ACC and myo-inositol in hippocampus and thalamus, but not with neuron-related metabolites. Together, the results show that age effects on glia-related metabolites scale with cognitive ageing in multiple brain regions. We conclude that 1H-MRS-derived glia-related markers may be of value in longitudinal studies of brain ageing. Significance statementNeurochemical ageing is an integral component of age-related cognitive decline. Proton MR spectroscopy (1H-MRS) studies of in vivo neurochemical changes across the lifespan have, however, yielded inconclusive results. Due to the higher spectral resolution and sensitivity, 7 tesla 1H-MRS has potential to improve consistency of the results. Here we apply this technique to demonstrate that glia-related metabolites are elevated in older age in anterior cingulate cortex, hippocampus and thalamus with a novel link to cognitive ageing of visuo-spatial working memory. This study is the first to investigate normal ageing in these brain regions using 7 tesla 1H-MRS and the results indicate that glia-related metabolites could be of value in longitudinal studies of cognitive ageing.

Source connections

Explore related subjects

neurosciencePreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lind, A., Boraxbekk, C.-J., Petersen, E. T., Paulson, O. B., Siebner, H., Marsman, A.. 2019-12-11. Regional glia-related metabolite levels are higher at older age and scale negatively with visuo-spatial working memory: A cross-sectional proton MR spectroscopy study at 7 tesla on normal cognitive ageing. https://doi.org/10.1101/864496

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Novel Tau Interaction Partners as Potential Biomarkers and Therapeutic Targets in Neurodegenerative Diseases

Alzheimers disease is a progressive neurodegenerative disorder leading to cognitive decline and ultimately death. One of the main hallmarks of this disease is the accumulation of pathological tau protein into neurofibrillary tangles. To better understand these pathological mechanisms, it is essential to characterize the tau protein interactome in health and disease. In this study, we performed a yeast two-hybrid screening using a human brain cDNA library, from which we identified 15 novel tau-interacting proteins that bind to full-length human tau, or its fragments: the N-terminus, microtubule-binding domain, or C-terminus. We subsequently validated these novel interactions using in vitro co-immunoprecipitation and colocalization assays with both physiological and pathological tau isoforms. Furthermore, their interactions with the human tau protein were analyzed using surface plasmon resonance. Finally, an in silico interactome analysis of these newly discovered tau-binding partners revealed several additional interactors that can link them to downstream processes critical to neurodegenerative pathways Our findings offer fresh insights into tau biology and highlight novel targets for therapeutic intervention and biomarker development.

neuroscience↗
bioRxiv2026

Early visual cortex is not functionally necessary for temporal attention: A TMS study

Temporal attention enhances the selective processing of information at a specific point in time and improves perception. Previous neuroimaging studies investigating its neural mechanisms have either conflated temporal attention with temporal expectation or provided correlational evidence. Thus, whether early visual cortex is functionally necessary for temporal attention remains unknown. Here, we combined psychophysics with transcranial magnetic stimulation (TMS) to examine whether V1/V2 are functionally necessary and play a causal role in temporal attention. Observers performed an orientation-discrimination task in which two consecutive stimuli, T1 and T2, were presented in the periphery, preceded by a precue providing either valid or neutral temporal information. Double-pulse TMS was delivered under four conditions: at T1 (T1-TMS), at T2 (T2-TMS), at both T1 and T2 (both-TMS), or not at all (none-TMS), to assess its effects on temporal attention and the efficacy of the stimulation was verified by pupil size analysis. Behavioral results revealed robust temporal attention benefits on d', reaction time, and the Balanced Integration Score (BIS) across all four TMS conditions, indicating that the benefits of temporal attention were unaffected by occipital TMS. Furthermore, pupil dilation was largest in the both-TMS condition, followed by the T1-TMS and T2-TMS conditions, and smallest in the none-TMS condition, providing physiological verification of the stimulation protocol. Together, these findings reveal the first causal evidence that the early visual cortex is not functionally necessary for endogenous temporal attention.

neuroscience↗
bioRxiv2026

Disentanglement of persistent and dynamic neural substrates of working memory

Competing theories of working memory have alternatively emphasized the importance of persistent and dynamic substrates of this cognitive function. Here, we directly tested these theories by computationally isolating the contributions of persistent and dynamic activity to working memory. We analyzed neuronal population activity recordings in macaques doing match/non-match working memory tasks. We first extracted signatures of persistent and dynamic activity through cue-specific temporal means, temporal principal components, and correlations of activity patterns across task epochs. We then generated synthetic data constrained by these signatures, and decoded cue stimuli from these data, separately from persistent and non-persistent neurons. We found that high decoding performance arose from a nuanced interplay of persistent and dynamic activity. Specifically, we could decode stimuli at empirical or above-chance levels across all tasks only from persistent neurons, but only after constraining correlations of activity patterns across epochs. In this way, we showed distinct roles for persistent and dynamic neuronal activity that help to unify two competing theories of working memory. More broadly, we also advanced computational controlled experiments as a principled framework for adjudicating between competing models of neuronal population activity.

neuroscience↗