Diffusion Tensor Imaging-Along the Perivascular-Space Index Is Associated with Disease Progression in Parkinson's Disease.

Background: The glymphatic clearance pathway is a waste clearance system that allows for removal of soluble proteins such as amyloid β (Aβ) from the brain. Higher Aβ levels are associated with cognitive dysfunction in Parkinson's disease (PD). Diffusion tensor imaging-along the perivascular space (DTI-ALPS) is an imaging measure proposed to indirectly measure glymphatic function.

Quantitative sleep electroencephalogram and cognitive performance in Parkinson's disease with and without rapid eye movement sleep behavior disorder.

Introduction: Parkinson's disease (PD) patients with REM sleep behavior disorder (RBD) are at greater risk for cognitive decline and RBD has been associated with alterations in sleep-related EEG oscillations. This study evaluates differences in sleep quantitative EEG (qEEG) and cognition in PD participants with (PD-RBD) and without RBD (PD-no-RBD).

Methods: In this cross-sectional study, polysomnography (PSG)-derived qEEG and a comprehensive level II neuropsychological assessment were compared between PD-RBD ( = 21) and PD-no-RBD ( = 31).

Quantitative Sleep Electroencephalogram in Parkinson's Disease: A Case-Control Study.

Background: Sleep disorders are common in Parkinson's disease (PD) and include alterations in sleep-related EEG oscillations.

Objective: This case-control study tested the hypothesis that patients with PD would have a lower density of Scalp-Slow Wave (SW) oscillations and higher slow-to-fast frequencies ratio in rapid eye movement (REM) sleep than non-PD controls. Other sleep-related quantitative EEG (qEEG) features were also examined, including SW morphology, sleep spindles, and Scalp-SW spindle phase-amplitude coupling.

Effects of exercise on sleep spindles in Parkinson's disease.

Background: In a randomized, controlled trial, we showed that high-intensity rehabilitation, combining resistance training and body-weight interval training, improves sleep efficiency in Parkinson's disease (PD). Quantitative sleep EEG (sleep qEEG) features, including sleep spindles, are altered in aging and in neurodegenerative disease.

Objective: The objective of this post-hoc analysis was to determine the effects of exercise, in comparison to a sleep hygiene, no-exercise control group, on the quantitative characteristics of sleep spindle morphology in PD.

Sex-related differences in violence exposure, neural reactivity to threat, and mental health.

The prefrontal cortex (PFC), hippocampus, and amygdala play an important role in emotional health. However, adverse life events (e.g.

Taking the Time to Assess Cognition in Parkinson's Disease: The Clock Drawing Test.

Background: Cognitive impairment is common and disabling in Parkinson's disease (PD). Cognitive testing can be time consuming in the clinical setting. One rapid test to detect cognitive impairment in non-PD populations is the Clock Drawing Test (CDT), which calls upon the brain's executive and visuospatial abilities to draw a clock designating a certain time.

Slow Wave Sleep and EEG Delta Spectral Power are Associated with Cognitive Function in Parkinson's Disease.

Background: Cognitive and sleep dysfunction are common non-motor symptoms in Parkinson's disease (PD).

Objective: Determine the relationship between slow wave sleep (SWS) and cognitive performance in PD.

Methods: Thirty-two PD participants were evaluated with polysomnography and a comprehensive level II neurocognitive battery, as defined by the Movement Disorders Society Task Force for diagnosis of PD-mild cognitive impairment.

Randomized, Controlled Trial of Exercise on Objective and Subjective Sleep in Parkinson's Disease.

Background: Sleep dysfunction is common and disabling in persons with Parkinson's Disease (PD). Exercise improves motor symptoms and subjective sleep quality in PD, but there are no published studies evaluating the impact of exercise on objective sleep outcomes. The goal of this study was to to determine if high-intensity exercise rehabilitation combining resistance training and body-weight interval training, compared with a sleep hygiene control improved objective sleep outcomes in PD.

Negative life experiences contribute to racial differences in the neural response to threat.

Threat-related emotional function is supported by a neural circuit that includes the prefrontal cortex (PFC), hippocampus, and amygdala. The function of this neural circuit is altered by negative life experiences, which can potentially affect threat-related emotional processes. Notably, Black-American individuals disproportionately endure negative life experiences compared to White-American individuals.

Amygdala and prefrontal cortex activity varies with individual differences in the emotional response to psychosocial stress.

Stress elicits a variety of psychophysiological responses that show large interindividual variability. Determining the neural mechanisms that mediate individual differences in the emotional response to stress would provide new insight that would have important implications for understanding stress-related disorders. Therefore, the present study examined individual differences in the relationship between brain activity and the emotional response to stress.

Psychosocial stress reactivity is associated with decreased whole-brain network efficiency and increased amygdala centrality.

Cognitive and emotional functions are supported by the coordinated activity of a distributed network of brain regions. This coordinated activity may be disrupted by psychosocial stress, resulting in the dysfunction of cognitive and emotional processes. Graph theory is a mathematical approach to assess coordinated brain activity that can estimate the efficiency of information flow and determine the centrality of brain regions within a larger distributed neural network.

Trauma exposure acutely alters neural function during Pavlovian fear conditioning.

Posttraumatic stress disorder (PTSD) is associated with dysfunction of the neural circuitry that supports fear learning and memory processes. However, much of what is known about neural dysfunction in PTSD is based on research in chronic PTSD populations. Less is known about neural function that supports fear learning acutely following trauma exposure.

Anticipatory stress associated with functional magnetic resonance imaging: Implications for psychosocial stress research.

Stress tasks performed during functional magnetic resonance imaging (fMRI) elicit a relatively small cortisol response compared to stress tasks completed in a traditional behavioral laboratory, which may be due to apprehension of fMRI that elicits an anticipatory stress response. The present study investigated whether anticipatory stress is greater prior to research completed in an MRI environment than in a traditional behavioral laboratory. Anticipatory stress (indexed by cortisol) was greater prior to testing in the MRI environment than traditional behavioral laboratory.

High-Intensity Exercise Acutely Increases Substantia Nigra and Prefrontal Brain Activity in Parkinson's Disease.

BACKGROUND Pathologic alterations in resting-state brain activity patterns exist among individuals with Parkinson's disease (PD). Since physical exercise alters resting-state brain activity in non-PD populations and improves PD symptoms, we assessed the acute effect of exercise on resting-state brain activity in exercise-trained individuals with PD. MATERIAL AND METHODS Resting-state functional magnetic resonance imaging (fMRI) was collected twice for 17 PD participants at the conclusion of an exercise intervention.

Pedestrian safety in patients with Parkinson's disease: A case-control study.

Background: Patients with Parkinson's disease experience debilitating motor symptoms as well as nonmotor symptoms, such as cognitive dysfunction and sleep disorders. This constellation of symptoms has the potential to negatively influence pedestrian safety. The objective of this study was to investigate the association of motor symptoms, daytime sleepiness, impaired vigilance, and cognitive dysfunction with pedestrian behavior in patients with Parkinson's disease and healthy older adults.

Glutamate/glutamine concentrations in the dorsal anterior cingulate vary with Post-Traumatic Stress Disorder symptoms.

Trauma and stress-related disorders (e.g., Acute Stress Disorder; ASD and Post-Traumatic Stress Disorder; PTSD) that develop following a traumatic event are characterized by cognitive-affective dysfunction.

Prefrontal Cortex Activity Is Associated with Biobehavioral Components of the Stress Response.

Contemporary theory suggests that prefrontal cortex (PFC) function is associated with individual variability in the psychobiology of the stress response. Advancing our understanding of this complex biobehavioral pathway has potential to provide insight into processes that determine individual differences in stress susceptibility. The present study used functional magnetic resonance imaging to examine brain activity during a variation of the Montreal Imaging Stress Task (MIST) in 53 young adults.

Exploring the Neurocircuitry Underpinning Predictability of Threat in Soldiers with PTSD Compared to Deployment Exposed Controls.

Background: Prior work examining emotional dysregulation observed in posttraumatic stress disorder (PTSD) has primarily been limited to fear-learning processes specific to anticipation, habituation, and extinction of threat. In contrast, the response to threat itself has not been systematically evaluated.

Objective: To explore potential disruption in fear conditioning neurocircuitry in service members with PTSD, specifically in response to predictable unpredictable threats.

Neural mechanisms of human temporal fear conditioning.

Learning the temporal relationship between a warning cue (conditioned stimulus; CS) and aversive threat (unconditioned stimulus; UCS) is an important aspect of Pavlovian conditioning. Although prior functional magnetic resonance imaging (fMRI) research has identified brain regions that support Pavlovian conditioning, it remains unclear whether these regions support time-related processes important for this type of associative learning. Elucidating the neural substrates of temporal conditioning is important for a complete understanding of the Pavlovian conditioning process.

Affective state and locus of control modulate the neural response to threat.

The ability to regulate the emotional response to threat is critical to healthy emotional function. However, the response to threat varies considerably from person-to-person. This variability may be partially explained by differences in emotional processes, such as locus of control and affective state, which vary across individuals.

Controllability modulates the neural response to predictable but not unpredictable threat in humans.

Stress resilience is mediated, in part, by our ability to predict and control threats within our environment. Therefore, determining the neural mechanisms that regulate the emotional response to predictable and controllable threats may provide important new insight into the processes that mediate resilience to emotional dysfunction and guide the future development of interventions for anxiety disorders. To better understand the effect of predictability and controllability on threat-related brain activity in humans, two groups of healthy volunteers participated in a yoked Pavlovian fear conditioning study during functional magnetic resonance imaging (fMRI).

The amygdala mediates the emotional modulation of threat-elicited skin conductance response.

The ability to respond adaptively to threats in a changing environment is an important emotional function. The amygdala is a critical component of the neural circuit that mediates many emotion-related processes, and thus likely plays an important role in modulating the peripheral emotional response to threat. However, prior research has largely focused on the amygdala's response to stimuli that signal impending threat, giving less attention to the amygdala's response to the threat itself.

Neural substrates underlying learning-related changes of the unconditioned fear response.

The ability to predict an impending threat during Pavlovian conditioning diminishes the emotional response that is produced once the threat is encountered. Diminution of the threat response appears to be mediated by somewhat independent associative learning and expectancy-related processes. Therefore, the present study was designed to better understand the neural mechanisms that support associative learning processes, independent of expectancy, that influence the emotional response to a threat.

Human trace fear conditioning: right-lateralized cortical activity supports trace-interval processes.

Pavlovian conditioning requires the convergence and simultaneous activation of neural circuitry that supports conditioned stimulus (CS) and unconditioned stimulus (US) processes. However, in trace conditioning, the CS and US are separated by a period of time called the trace interval, and thus do not overlap. Therefore, determining brain regions that support associative learning by maintaining a CS representation during the trace interval is an important issue for conditioning research.