Characterization of pulsations in the brain and cerebrospinal fluid using ultra‐high field magnetic resonance imaging.

Background: Brain fluid flow plays a crucial role in maintaining brain health by eliminating potentially harmful waste products like amyloid‐beta and tau [1‐2]. This process is potentially facilitated by pulsations in the perivascular space, influenced by the neurovascular unit and autonomic nervous system, which may vary in brain diseases such as Alzheimer’s disease (AD) [3‐4]. Using a 7 Tesla MRI scanner and ultrafast echo‐planar imaging (EPI), we developed a non‐invasive neuroimaging methodology to characterize the in‐vivo frequency and amplitude responses of pulsations of cerebrospinal fluid (CSF) flow.

Characterization of pulsations in the brain and cerebrospinal fluid using ultra‐high field magnetic resonance imaging.

Background: Brain fluid flow plays a crucial role in maintaining brain health by eliminating potentially harmful waste products like amyloid‐beta and tau [1‐2]. This process is potentially facilitated by pulsations in the perivascular space, influenced by the neurovascular unit and autonomic nervous system, which may vary in brain diseases such as Alzheimer’s disease (AD) [3‐4]. Using a 7 Tesla MRI scanner and ultrafast echo‐planar imaging (EPI), we developed a non‐invasive neuroimaging methodology to characterize the in‐vivo frequency and amplitude responses of pulsations of cerebrospinal fluid (CSF) flow.

A pilot time-in-bed restriction intervention behaviorally enhances slow-wave activity in older adults.

Introduction: Identifying intervention methods that target sleep characteristics involved in memory processing is a priority for the field of cognitive aging. Older adults with greater sleep efficiency and non-rapid eye movement slow-wave activity (SWA) (0.5-4 Hz electroencephalographic activity) tend to exhibit better memory and cognitive abilities.

Characterization of pulsations in the brain and cerebrospinal fluid using ultra-high field magnetic resonance imaging.

The development of innovative non-invasive neuroimaging methods and biomarkers is critical for studying brain disease. Imaging of cerebrospinal fluid (CSF) pulsatility may inform the brain fluid dynamics involved in clearance of cerebral metabolic waste. In this work, we developed a methodology to characterize the frequency and spatial localization of whole brain CSF pulsations in humans.

Characterization of oscillations in the brain and cerebrospinal fluid using ultra-high field magnetic resonance imaging.

Development of innovative non-invasive neuroimaging methods and biomarkers are critical for studying brain disease. In this work, we have developed a methodology to characterize the frequency responses and spatial localization of oscillations and movements of cerebrospinal fluid (CSF) flow in the human brain. Using 7 Tesla human MRI and ultrafast echo-planar imaging (EPI), images were obtained to capture CSF oscillations and movements.

The Interactive Role of Sleep and Circadian Rhythms in Episodic Memory in Older Adults.

Adequate sleep is essential for healthy physical, emotional, and cognitive functioning, including memory. However, sleep ability worsens with increasing age. Older adults on average have shorter sleep durations and more disrupted sleep compared with younger adults.

Cardiometabolic function in retired night shift workers and retired day workers.

Night shift work is associated with poor cardiometabolic outcomes, even post-retirement. However, the characteristics of cardiometabolic function in retired night shift workers (RNSW) compared to retired day workers (RDW) are not well-understood. Rigorous characterization of cardiometabolic dysfunction in RNSW and RDW will inform targeted risk stratification for RNSW.

Smart Phone/Ecological Momentary Assessment of Sleep and Daytime Symptoms Among Older Adults With Insomnia.

Objectives: To employ smart phone/ecological momentary assessment (EMA) methods to evaluate the impact of insomnia on daytime symptoms among older adults.

Design: Prospective cohort study SETTING: Academic medical center PARTICIPANTS: Twenty-nine older adults with insomnia (M age = 67.5 ± 6.

Effects of continuous positive airway pressure treatment on sleep architecture in adults with obstructive sleep apnea and type 2 diabetes.

Obstructive sleep apnea (OSA) severely impacts sleep and has long-term health consequences. Treating sleep apnea with continuous positive airway pressure (CPAP) not only relieves obstructed breathing, but also improves sleep. CPAP improves sleep by reducing apnea-induced awakenings.

Physical Exertion Partially Mitigates Task-Switching Deficits From Sleep Loss: Implications for Firefighters.

Objective: The aim of the study is to investigate effects of physical exertion on cognitive deficits from sleep loss under conditions that mimic a firefighting scenario.

Methods: Twenty-four male participants completed a crossover study design with 3 conditions: total sleep deprivation, sleep disruption (three 60-minute awakenings), and rested control. Participants then completed 50 minutes of a physical exertion task involving treadmill exercise in a heated room while wearing firefighter protective clothing.

Slow-oscillation activity is reduced and high frequency activity is elevated in older adults with insomnia.

Study Objectives: High-frequency electroencephalographic activity (> 16 Hz activity) is often elevated during nonrapid eye movement sleep among individuals with insomnia, in line with the hyperarousal theory of insomnia. Evidence regarding sleep depth marked by slow-wave activity (< 4 Hz) is more mixed. Distinguishing subcomponents of slow-wave activity (slow-oscillation [< 1 Hz] or delta activity [1-4 Hz)]) may be critical in understanding these discrepancies, given that these oscillations have different neural generators and are functionally distinct.

Does objectively-assessed sleep moderate the association between history of major depressive disorder and task-switching?

Background: Executive function and psychomotor speed are consistently impaired in patients with major depressive disorder (MDD). Persistent cognitive impairments after depression remission are thought to reflect "scarring" from the neurotoxic effects of hypothalamic-pituitary-adrenal axis activity during a depressive episode. As sleep also deteriorates with depression and restores daytime executive functions, we examined whether adequate sleep could be protective against task-switching and psychomotor impairments associated with a history of MDD.

Infection with Herpes Simplex virus type 1 (HSV-1) and sleep: The dog that did not bark.

Persistent infection with Herpes Simplex viruses (HSV) and other brain infections is consistently associated with cognitive impairment. These infections can also affect sleep. Thus, sleep abnormalities could explain the cognitive dysfunction.

Sleep moderates the relationship between amyloid beta and memory recall.

Amyloid-β (Aβ) accumulation is a hallmark of Alzheimer's disease, although Aβ alone may be insufficient to cause impairments. Modifiable health factors, including sleep, may mitigate functional symptoms of neurodegeneration. We assessed whether sleep moderated the relationship between Aβ and cognitive performance in 41 older adults, mean age 83 years.

Slow-Wave Activity Enhancement to Improve Cognition.

Slow-wave activity (SWA), and its coupling with other sleep features, reorganizes cortical circuitry, supporting cognition. This raises the question: can cognition be improved through SWA enhancement? SWA enhancement techniques range from behavioral interventions (such as exercise), which have high feasibility but low specificity, to laboratory-based techniques (such as transcranial stimulation), which have high specificity but are less feasible for widespread use. In this review we describe the pathways through which SWA is enhanced.

Task switching in older adults with and without insomnia.

Background: Task-switching deficits are common in older adults and in those with insomnia. Such deficits may be driven by difficulties with sleep continuity and dampened homeostatic sleep drive.

Objective: To identify the aspects of task switching affected by insomnia and its treatment, and to determine whether such effects are associated with sleep continuity and homeostatic sleep drive.

Physical Activity and Cognition: A Mediating Role of Efficient Sleep.

Objective: Physical activity benefits executive control, but the mechanism through which this benefit occurs is unclear. Sleep is a candidate mechanism given that it improves with exercise and has restorative effects on the prefrontal cortex. The present cross-sectional study examined the mediating role of sleep in the relationship between physical activity and executive control in young and older adults.

Sleep-Wake Differences in Relative Regional Cerebral Metabolic Rate for Glucose among Patients with Insomnia Compared with Good Sleepers.

Study Objectives: The neurobiological mechanisms of insomnia may involve altered patterns of activation across sleep-wake states in brain regions associated with cognition, self-referential processes, affect, and sleep-wake promotion. The objective of this study was to compare relative regional cerebral metabolic rate for glucose (rCMR) in these brain regions across wake and nonrapid eye movement (NREM) sleep states in patients with primary insomnia (PI) and good sleeper controls (GS).

Methods: Participants included 44 PI and 40 GS matched for age (mean = 37 y old, range 21-60), sex, and race.

The role of non-rapid eye movement slow-wave activity in prefrontal metabolism across young and middle-aged adults.

Electroencephalographic slow-wave activity (0.5-4 Hz) during non-rapid eye movement (NREM) sleep is a marker for cortical reorganization, particularly within the prefrontal cortex. Greater slow wave activity during sleep may promote greater waking prefrontal metabolic rate and, in turn, executive function.

Changes in Cognitive Performance Are Associated with Changes in Sleep in Older Adults With Insomnia.

The present study examined sleep features associated with cognition in older adults and examined whether sleep changes following insomnia treatment were associated with cognitive improvements. Polysomnography and cognition (recall, working memory, and reasoning) were assessed before and after an insomnia intervention (Brief Behavioral Treatment of Insomnia [BBTI] or information control [IC]) in 77 older adults with insomnia. Baseline wake-after-sleep-onset (WASO) was associated with recall.

Role of sleep continuity and total sleep time in executive function across the adult lifespan.

The importance of sleep for cognition in young adults is well established, but the role of habitual sleep behavior in cognition across the adult life span remains unknown. We examined the relationship between sleep continuity and total sleep time as assessed with a sleep-detection device, and cognitive performance using a battery of tasks in young (n = 59, mean age = 23.05) and older (n = 53, mean age = 62.