COVID-19 Exacerbates Neurovascular Uncoupling and Contributes to Endothelial Dysfunction in Patients with Mild Cognitive Impairment.

Mild cognitive impairment (MCI) affects nearly 20% of older adults worldwide, with no targetable interventions for prevention. COVID-19 adversely affects cognition, with >70% of older adults with Long COVID presenting with cognitive complaints. Neurovascular coupling (NVC), an essential mechanism of cognitive function, declines with aging and is further attenuated in neurocognitive disorders.

Time-restricted eating for prevention of age-related vascular cognitive decline in older adults: A protocol for a single-arm open-label interventional trial.

Age-related cerebromicrovascular endothelial dysfunction underlies the initiation and progression of cognitive dysfunction and dementia, thus increasing the susceptibility of older adults to such conditions. Normal brain function requires dynamic adjustment of cerebral blood flow to meet the energetic demands of active neurons, which is achieved the homeostatic mechanism neurovascular coupling (NVC). In this context, therapeutical strategies aimed at rescuing or preserving NVC responses can delay the incidence or mitigate the severity of age-related cognitive dysfunction, and time-restricted eating (TRE) is a potential candidate for such a strategy.

Energy metabolism dysregulation, cerebrovascular aging, and time-restricted eating: Current evidence and proof-of-concept findings.

Dysregulated energy metabolism is a hallmark of aging, including brain aging; thus, strategies to restore normal metabolic regulation are at the forefront of aging research. Intermittent fasting, particularly time-restricted eating (TRE), is one of these strategies. Despite its well-established effectiveness in improving metabolic outcomes in older adults, the effect of TRE on preserving or improving cerebrovascular health during aging remains underexplored.

Neurovascular coupling, functional connectivity, and cerebrovascular endothelial extracellular vesicles as biomarkers of mild cognitive impairment.

Introduction: Mild cognitive impairment (MCI) is a prodromal stage of dementia. Understanding the mechanistic changes from healthy aging to MCI is critical for comprehending disease progression and enabling preventative intervention.

Methods: Patients with MCI and age-matched controls (CN) were administered cognitive tasks during functional near-infrared spectroscopy (fNIRS) recording, and changes in plasma levels of extracellular vesicles (EVs) were assessed using small-particle flow cytometry.

Combining detrended cross-correlation analysis with Riemannian geometry-based classification for improved brain-computer interface performance.

Riemannian geometry-based classification (RGBC) gained popularity in the field of brain-computer interfaces (BCIs) lately, due to its ability to deal with non-stationarities arising in electroencephalography (EEG) data. Domain adaptation, however, is most often performed on sample covariance matrices (SCMs) obtained from EEG data, and thus might not fully account for components affecting covariance estimation itself, such as regional trends. Detrended cross-correlation analysis (DCCA) can be utilized to estimate the covariance structure of such signals, yet it is computationally expensive in its original form.

Fingerprints of decreased cognitive performance on fractal connectivity dynamics in healthy aging.

Analysis of brain functional connectivity (FC) could provide insight in how and why cognitive functions decline even in healthy aging (HA). Despite FC being established as fluctuating over time even in the resting state (RS), dynamic functional connectivity (DFC) studies involving healthy elderly individuals and assessing how these patterns relate to cognitive performance are yet scarce. In our recent study we showed that fractal temporal scaling of functional connections in RS is not only reduced in HA, but also predicts increased response latency and reduced task solving accuracy.

Scale-Free Functional Brain Networks Exhibit Increased Connectivity, Are More Integrated and Less Segregated in Patients with Parkinson's Disease following Dopaminergic Treatment.

Dopaminergic treatment (DT), the standard therapy for Parkinson's disease (PD), alters the dynamics of functional brain networks at specific time scales. Here, we explore the scale-free functional connectivity (FC) in the PD population and how it is affected by DT. We analyzed the electroencephalogram of: (i) 15 PD patients during DT (ON) and after DT washout (OFF) and (ii) 16 healthy control individuals (HC).

Resting-state fractal brain connectivity is associated with impaired cognitive performance in healthy aging.

Aging affects cognitive functions even in the absence of ongoing pathologies. The neurophysiological basis of age-related cognitive decline (CD), however, is not completely understood. Alterations in both functional brain connectivity and in the fractal scaling of neuronal dynamics have been linked to aging and cognitive performance.

Real-Time Algorithm for Detrended Cross-Correlation Analysis of Long-Range Coupled Processes.

Assessing power-law cross-correlations between a pair - or among a set - of processes is of great significance in diverse fields of analyses ranging from neuroscience to financial markets. In most cases such analyses are computationally expensive and thus carried out offline once the entire signal is obtained. However, many applications - such as mental state monitoring or financial forecasting - call for fast algorithms capable of estimating scale-free coupling in real time.

Multiple-Resampling Cross-Spectral Analysis: An Unbiased Tool for Estimating Fractal Connectivity With an Application to Neurophysiological Signals.

Investigating scale-free (i.e., fractal) functional connectivity in the brain has recently attracted increasing attention.

Multifractal Functional Connectivity Analysis of Electroencephalogram Reveals Reorganization of Brain Networks in a Visual Pattern Recognition Paradigm.

The human brain consists of anatomically distant neuronal assemblies that are interconnected via a myriad of synapses. This anatomical network provides the neurophysiological wiring framework for functional connectivity (FC), which is essential for higher-order brain functions. While several studies have explored the scale-specific FC, the scale-free (i.

Separating scale-free and oscillatory components of neural activity in schizophrenia.

Introduction: Alterations in narrow-band spectral power of electroencephalography (EEG) recordings are commonly reported in patients with schizophrenia (SZ). It is well established however that electrophysiological signals comprise a broadband scale-free (or fractal) component generated by mechanisms different from those producing oscillatory neural activity. Despite this known feature, it has not yet been investigated if spectral abnormalities found in SZ could be attributed to scale-free or oscillatory brain function.

Decreased connection density and modularity of functional brain networks during n-back working memory paradigm.

Introduction: Investigating how the brain adapts to increased mental workload through large-scale functional reorganization appears as an important research question. Functional connectivity (FC) aims at capturing how disparate regions of the brain dynamically interact, while graph theory provides tools for the topological characterization of the reconstructed functional networks. Although numerous studies investigated how FC is altered in response to increased working memory (WM) demand, current results are still contradictory as few studies confirmed the robustness of these findings in a low-density setting.