Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort

Cocoa flavanols (CF) positively influence physiological processes in ways that suggest their consumption may improve aspects of cognitive function. This study investigated the acute cognitive and subjective effects of CF consumption during sustained mental demand. In this randomized, controlled, double-blinded, balanced, three period crossover trial 30 healthy adults consumed drinks containing 520 mg, 994 mg CF and a matched control, with a three-day washout between drinks. Assessments included the state anxiety inventory and repeated 10-min cycles of a Cognitive Demand Battery comprising of two serial subtraction tasks (Serial Threes and Serial Sevens), a Rapid Visual Information Processing (RVIP) task and a mental fatigue scale, over the course of 1 h. Consumption of both 520 mg and 994 mg CF significantly improved Serial Threes performance. The 994 mg CF beverage significantly speeded RVIP responses but also resulted in more errors during Serial Sevens. Increases in self-reported mental fatigue were significantly attenuated by the consumption of the 520 mg CF beverage only. This is the first report of acute cognitive improvements following CF consumption in healthy adults. While the mechanisms underlying the effects are unknown they may be related to known effects of CF on endothelial function and blood flow

Dynamic cerebral autoregulation after intracerebral hemorrhage: A case-control study

<p>Abstract</p> <p>Background</p> <p>Dynamic cerebral autoregulation after intracerebral hemorrhage (ICH) remains poorly understood. We performed a case-control study to compare dynamic autoregulation between ICH patients and healthy controls.</p> <p>Methods</p> <p>Twenty-one patients (66 ± 15 years) with early (< 72 hours) lobar or basal ganglia ICH were prospectively studied and compared to twenty-three age-matched controls (65 ± 9 years). Continuous measures of mean flow velocity (MFV) in the middle cerebral artery and mean arterial blood pressure (MAP) were obtained over 5 min. Cerebrovascular resistance index (CVR_i) was calculated as the ratio of MAP to MFV. Dynamic cerebral autoregulation was assessed using transfer function analysis of spontaneous MAP and MFV oscillations in the low (0.03-0.15 Hz) and high (0.15-0.5 Hz) frequency ranges.</p> <p>Results</p> <p>The ICH group demonstrated higher CVR_icompared to controls (ipsilateral: 1.91 ± 1.01 mmHg·s·cm^-1, <it>p </it>= 0.04; contralateral: 2.01 ± 1.24 mmHg·s·cm^-1, <it>p </it>= 0.04; vs. control: 1.42 ± 0.45 mmHg·s·cm^-1). The ICH group had higher gains than controls in the low (ipsilateral: 1.33 ± 0.58%/mmHg, <it>p </it>= 0.0005; contralateral: 1.47 ± 0.98%/mmHg, <it>p </it>= 0.004; vs. control: 0.82 ± 0.30%/mmHg) and high (ipsilateral: 2.11 ± 1.31%/mmHg, <it>p </it>< 0.0001; contralateral: 2.14 ± 1.49%/mmHg, <it>p </it>< 0.0001; vs. control: 0.66 ± 0.26%/mmHg) frequency ranges. The ICH group also had higher coherence in the contralateral hemisphere than the control (ICH contralateral: 0.53 ± 0.38, <it>p </it>= 0.02; vs. control: 0.38 ± 0.15) in the high frequency range.</p> <p>Conclusions</p> <p>Patients with ICH had higher gains in a wide range of frequency ranges compared to controls. These findings suggest that dynamic cerebral autoregulation may be less effective in the early days after ICH. Further study is needed to determine the relationship between hematoma size and severity of autoregulation impairment.</p

Age-related changes in global motion coherence: conflicting haemodynamic and perceptual responses

Our aim was to use both behavioural and neuroimaging data to identify indicators of perceptual decline in motion processing. We employed a global motion coherence task and functional Near Infrared Spectroscopy (fNIRS). Healthy adults (n = 72, 18-85) were recruited into the following groups: young (n = 28, mean age = 28), middle-aged (n = 22, mean age = 50), and older adults (n = 23, mean age = 70). Participants were assessed on their motion coherence thresholds at 3 different speeds using a psychophysical design. As expected, we report age group differences in motion processing as demonstrated by higher motion coherence thresholds in older adults. Crucially, we add correlational data showing that global motion perception declines linearly as a function of age. The associated fNIRS recordings provide a clear physiological correlate of global motion perception. The crux of this study lies in the robust linear correlation between age and haemodynamic response for both measures of oxygenation. We hypothesise that there is an increase in neural recruitment, necessitating an increase in metabolic need and blood flow, which presents as a higher oxygenated haemoglobin response. We report age-related changes in motion perception with poorer behavioural performance (high motion coherence thresholds) associated with an increased haemodynamic response

Impact of Flavonoids on Cellular and Molecular Mechanisms Underlying Age-Related Cognitive Decline and Neurodegeneration

Purpose of Review This review summarises the most recent evidence regarding the effects of dietary flavonoids on age-related cognitive decline and neurodegenerative diseases. Recent Findings Recent evidence indicates that plant-derived flavonoids may exert powerful actions on mammalian cognition and protect against the development of age-related cognitive decline and pathological neurodegeneration. The neuroprotective effects of flavonoids have been suggested to be due to interactions with the cellular and molecular architecture of brain regions responsible for memory. Summary Mechanisms for the beneficial effects of flavonoids on age-related cognitive decline and dementia are discussed, including modulating signalling pathways critical in controlling synaptic plasticity, reducing neuroinflammation, promoting vascular effects capable of stimulating new nerve cell growth in the hippocampus, bidirectional interactions with gut microbiota and attenuating the extracellular accumulation of pathological proteins. These processes are known to be important in maintaining optimal neuronal function and preventing age-related cognitive decline and neurodegeneration

Hepcidin Is Involved in Iron Regulation in the Ischemic Brain

Oxidative stress plays an important role in neuronal injuries caused by cerebral ischemia. It is well established that free iron increases significantly during ischemia and is responsible for oxidative damage in the brain. However, the mechanism of this ischemia-induced increase in iron is not completely understood. In this report, the middle cerebral artery occlusion (MCAO) rat model was performed and the mechanism of iron accumulation in cerebral ischemia-reperfusion was studied. The expression of L-ferritin was significantly increased in the cerebral cortex, hippocampus, and striatum on the ischemic side, whereas H-ferritin was reduced in the striatum and increased in the cerebral cortex and hippocampus. The expression level of the iron-export protein ferroportin1 (FPN1) significantly decreased, while the expression of transferrin receptor 1 (TfR1) was increased. In order to elucidate the mechanisms of FPN1 regulation, we studied the expression of the key regulator of FPN1, hepcidin. We observed that the hepcidin level was significantly elevated in the ischemic side of the brain. Knockdown hepcidin repressed the increasing of L-ferritin and decreasing of FPN1 invoked by ischemia-reperfusion. The results indicate that hepcidin is an important contributor to iron overload in cerebral ischemia. Furthermore, our results demonstrated that the levels of hypoxia-inducible factor-1α (HIF-1α) were significantly higher in the cerebral cortex, hippocampus and striatum on the ischemic side; therefore, the HIF-1α-mediated TfR1 expression may be another contributor to the iron overload in the ischemia-reperfusion brain

The MOBILIZE Boston Study: Design and methods of a prospective cohort study of novel risk factors for falls in an older population

<p>Abstract</p> <p>Background</p> <p>Falls are the sixth leading cause of death in elderly people in the U.S. Despite progress in understanding risk factors for falls, many suspected risk factors have not been adequately studied. Putative risk factors for falls such as pain, reductions in cerebral blood flow, somatosensory deficits, and foot disorders are poorly understood, in part because they pose measurement challenges, particularly for large observational studies.</p> <p>Methods</p> <p>The MOBILIZE Boston Study (MBS), an NIA-funded Program Project, is a prospective cohort study of a unique set of risk factors for falls in seniors in the Boston area. Using a door-to-door population-based recruitment, we have enrolled 765 persons aged 70 and older. The baseline assessment was conducted in 2 segments: a 3-hour home interview followed within 4 weeks by a 3-hour clinic examination. Measures included pain, cerebral hemodynamics, and foot disorders as well as established fall risk factors. For the falls follow-up, participants return fall calendar postcards to the research center at the end of each month. Reports of falls are followed-up with a telephone interview to assess circumstances and consequences of each fall. A second assessment is performed 18 months following baseline.</p> <p>Results</p> <p>Of the 2382 who met all eligibility criteria at the door, 1616 (67.8%) agreed to participate and were referred to the research center for further screening. The primary reason for ineligibility was inability to communicate in English. Results from the first 600 participants showed that participants are largely representative of seniors in the Boston area in terms of age, sex, race and Hispanic ethnicity. The average age of study participants was 77.9 years (s.d. 5.5) and nearly two-thirds were women. The study cohort was 78% white and 17% black. Many participants (39%) reported having fallen at least once in the year before baseline.</p> <p>Conclusion</p> <p>Our results demonstrate the feasibility of conducting comprehensive assessments, including rigorous physiologic measurements, in a diverse population of older adults to study non-traditional risk factors for falls and disability. The MBS will provide an important new data resource for examining novel risk factors for falls and mobility problems in the older population.</p

Harnessing hypoxic adaptation to prevent, treat, and repair stroke

The brain demands oxygen and glucose to fulfill its roles as the master regulator of body functions as diverse as bladder control and creative thinking. Chemical and electrical transmission in the nervous system is rapidly disrupted in stroke as a result of hypoxia and hypoglycemia. Despite being highly evolved in its architecture, the human brain appears to utilize phylogenetically conserved homeostatic strategies to combat hypoxia and ischemia. Specifically, several converging lines of inquiry have demonstrated that the transcription factor hypoxia-inducible factor-1 (HIF1-1) mediates the activation of a large cassette of genes involved in adaptation to hypoxia in surviving neurons after stroke. Accordingly, pharmacological or molecular approaches that engage hypoxic adaptation at the point of one of its sensors (e.g., inhibition of HIF prolyl 4 hydroxylases) leads to profound sparing of brain tissue and enhanced recovery of function. In this review, we discuss the potential mechanisms that could subserve protective and restorative effects of augmenting hypoxic adaptation in the brain. The strategy appears to involve HIF-dependent and HIF-independent pathways and more than 70 genes and proteins activated transcriptionally and post-transcriptionally that can act at cellular, local, and system levels to compensate for oxygen insufficiency. The breadth and depth of this homeostatic program offers a hopeful alternative to the current pessimism towards stroke therapeutics