Neural correlates of distinct cognitive phenotypes in early Parkinson's disease.

Objective: Cognitive decline is common in Parkinson's disease (PD), but changes can occur in a variety of cognitive domains. The lack of a single cognitive phenotype complicates diagnosis and tracking. In an earlier study we used a data-driven approach to identify distinct cognitive phenotypes of early PD.

Non-motor predictors of freezing of gait in Parkinson's disease.

Background: The etiology of freezing of gait in Parkinson's disease (PD) is yet to be clarified. Non-motor risk factors including cognitive impairment, sleep disturbance and mood disorders have been shown in freezing of gait.

Research Question: We aimed to determine the predictive value of non-motor features in freezing of gait development.

Dissociation of Executive and Attentional Elements of the Digit Span Task in a Population of Older Adults: A Latent Class Analysis.

The prevailing model for working memory proposes the existence of a "central executive" responsible for coordinating and prioritizing incoming information from sensory and association cortices. The Digit Span task is commonly used by clinicians to parse attentional and executive components of working memory; however, the interrelatedness of these constructs in the context of advanced age and neurodegenerative disease remains an area of active investigation. The current study details a procedure and rationale for the use of latent class analysis, a data-driven, person-centered method, in the investigation of older adults and dementia.

Affective Disruption from Social Rhythm and Behavioral Approach System (BAS) Sensitivities: A Test of the Integration of the Social Zeitgeber and BAS Theories of Bipolar Disorder.

The Behavioral Approach System (BAS)/Reward Hypersensitivity Theory and the Social Zeitgeber Theory are two biopsychosocial theories of bipolar spectrum disorders (BSD) that may work together to explain affective dysregulation. The present study examined whether BAS sensitivity is associated with affective symptoms via a) increased social rhythm disruption in response to BAS-relevant life events, or b) greater exposure to BAS events leading to social rhythm disruption and subsequent symptoms. Results indicated that high BAS individuals were more likely to experience social rhythm disruption following BAS-relevant events.

Associations between sleep disturbance, cognitive functioning and work disability in Bipolar Disorder.

Bipolar Disorder (BD) is associated with impairment in a number of areas including poor work functioning, often despite the remission of mood symptoms. The present study aimed to examine the role of sleep disturbance and cognitive functioning in occupational impairment in BD. Twenty-four euthymic BD participants and 24 healthy control participants completed a week of prospective assessment of sleep disruption via self-report and actigraphy, a battery of neuropsychological tests of executive functioning, working memory, and verbal learning, and assessments of work functioning.

Kindling of life stress in bipolar disorder: comparison of sensitization and autonomy models.

Research on life stress in bipolar disorder largely fails to account for the possibility of a dynamic relationship between psychosocial stress and episode initiation. The kindling hypothesis (Post, 1992) states that over the course of recurrent affective disorders, there is a weakening temporal relationship between major life stress and episode initiation that could reflect either a progressive sensitization or progressive autonomy to life stress. The present study involved a comprehensive and precise examination of the kindling hypothesis in 102 participants with bipolar II disorder that allowed for a direct comparison of sensitization and autonomy models.

Behavioral approach system sensitivity and risk taking interact to predict left-frontal EEG asymmetry.

The Behavioral Approach System (BAS) hypersensitivity theory of bipolar disorder (BD; Alloy & Abramson, 2010; Depue & Iacono, 1989) suggests that hyperreactivity in the BAS results in the extreme fluctuations of mood characteristic of BD. In addition to risk conferred by BAS hypersensitivity, cognitive and personality variables may play a role in determining risk. We evaluated relationships among BAS sensitivity, risk taking, and an electrophysiological correlate of approach motivation, relative left-frontal electroencephalography (EEG) asymmetry.

Life events and social rhythms in bipolar spectrum disorders: an examination of social rhythm sensitivity.

Objectives: To examine the presence of an underlying social rhythm sensitivity in individuals with bipolar spectrum disorders.

Methods: The present study examined the impact of life events on sleep loss and social rhythm disruption in 184 individuals with bipolar spectrum disorders (BSD) compared to 197 demographically similar normal controls (NC) drawn from the Longitudinal Investigation of Bipolar Spectrum Disorders (LIBS) project. Life events data were obtained at three time points, each spaced four months apart, and included information on the intensity of the event (high or low), valence (negative or positive), and levels of sleep loss and social rhythm disruption brought about the event.

Genetic and dietary effects on dendrites in the rat hypothalamic ventromedial nucleus.

Both genetic and environmental factors contribute to individual differences in body weight regulation. The present study examined a possible role for the dendritic arbor of hypothalamic ventromedial nucleus (VMH) neurons in a model of diet-induced obesity (DIO) in male rats. Rats were screened and selectively bred for being either susceptible, i.

Food restriction alters neuronal morphology in the hypothalamic ventromedial nucleus of male rats.

Several lines of evidence have implicated the hypothalamic ventromedial nucleus (VMH) in the control of caloric homeostasis. For example, the activity of VMH neurons depends on energy availability. We tested the hypothesis that energy balance may involve the remodeling of the dendritic arbor of VMH neurons.