Aims: Normal neurovascular coupling, mediated by the fine interplay and communication of cells within the neurovascular unit, is critical for maintaining normal brain activity and cognitive function. This study investigated whether, with advancing age there is disruption of neurovascular coupling and specific cellular components of the neurovascular unit, and whether the effects of increasing amyloid (a key feature of Alzheimer's disease) would exacerbate these changes.
Methods: Wild-type mice, in which amyloid deposition is absent, were compared to transgenic amyloid precursor protein (APP) littermates (TgSwDI) which develop age-dependent increases in amyloid. Baseline cerebral blood flow and responses to whisker stimulation were measured. Components of the neurovascular unit (astrocytes, end-feet, pericytes, microglia) were measured by immunohistochemistry.
Results: Neurovascular coupling was progressively impaired with increasing age (starting at 12 months) but was not further altered in TgSwDI mice. Aged mice showed reduced vascular pericyte coverage relative to young but this was not related to neurovascular function. Aged mice displayed significant reductions in astrocytic end-feet expression of aquaporin-4 on blood vessels compared to young mice, and a prominent increase in microglial proliferation which correlated with neurovascular function.
Conclusions: Strategies aimed to restore the loss of astrocytic end feet contact and reduce gliosis may improve neurovascular coupling.
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http://dx.doi.org/10.1111/nan.12375 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Neurovascular Unit Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea.
In ephaptic coupling, physically adjacent neurons influence one another's activity via the electric fields they generate. To date, the molecular mechanisms that mediate and modulate ephaptic coupling's effects remain poorly understood. Here, we show that the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel lateralizes the potentially mutual ephaptic inhibition between gustatory receptor neurons (GRNs).
View Article and Find Full Text PDFJ Biomed Opt
January 2025
TU Dresden, Carl Gustav Carus Faculty of Medicine, Anesthesiology and Intensive Care Medicine, Clinical Sensing and Monitoring, Dresden, Germany.
Significance: The precise identification and preservation of functional brain areas during neurosurgery are crucial for optimizing surgical outcomes and minimizing postoperative deficits. Intraoperative imaging plays a vital role in this context, offering insights that guide surgeons in protecting critical cortical regions.
Aim: We aim to evaluate and compare the efficacy of intraoperative thermal imaging (ITI) and intraoperative optical imaging (IOI) in detecting the primary somatosensory cortex, providing a detailed assessment of their potential integration into surgical practice.
J Cereb Blood Flow Metab
January 2025
Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO, USA.
Regional blood flow within the brain is tightly coupled to regional neuronal activity, a process known as neurovascular coupling (NVC). In this study, we demonstrate the striking role of SUR2- and Kir6.1-dependent ATP-sensitive potassium (K) channels in control of NVC in the sensory cortex of conscious mice, in response to mechanical stimuli.
View Article and Find Full Text PDFJ Neurophysiol
January 2025
Department of Biomedical Engineering, Georgia Institute of Technology and Emory University.
The brain is a complex neural network whose functional dynamics offer valuable insights into behavioral performance and health. Advances in fMRI have provided a unique window into studying human brain networks, providing us with a powerful tool for clinical research. Yet many questions about the underlying correlates between spontaneous fMRI and neural activity remain poorly understood, limiting the impact of this research.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Radiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
The alteration of neurovascular coupling (NVC), where acute localized blood flow increases following neural activity, plays a key role in several neurovascular processes including aging and neurodegeneration. While not equivalent to NVC, the coupling between simultaneously measured cerebral blood flow (CBF) with arterial spin labeling (ASL) and blood oxygenation dependent (BOLD) signals, can also be affected. Moreover, the acquisition of BOLD data allows the assessment of resting state (RS) fMRI metrics.
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