Assessing brain-wide outcomes of dopamine system activation in the living rodent brain.

In a recent study, Haas, Bravo, and colleagues integrated optogenetic stimulation with simultaneous functional in vivo positron emission tomography (PET)/magnetic resonance imaging (MRI) measurements in rats. By activating the nigrostriatal pathway in the substantia nigra pars compacta (SNc), they observed concurrent metabolic and hemodynamic fluctuations associated with the dopaminergic pathway in living animals at the whole-brain level.

Comparison of Plasma p-tau217 and [F]FDG-PET for Identifying Alzheimer Disease in People With Early-Onset or Atypical Dementia.

Background And Objectives: To compare the diagnostic performance of an immunoassay for plasma concentrations of phosphorylated tau (p-tau) 217 with visual assessments of fluorine-18 fluorodeoxyglucose [F]FDG-PET in individuals who meet appropriate use criteria for Alzheimer dementia (AD) biomarker assessments.

Methods: We performed a retrospective analysis of individuals with early-onset (age <65 years at onset) and/or atypical dementia (features other than memory at onset), who were evaluated at a tertiary care memory clinic. All participants underwent measurements of CSF biomarkers (Aβ42, p-tau181, and total tau levels), as well as [F]FDG-PET scans, amyloid-PET scans, and plasma p-tau217 quantifications.

Progeny array analysis to estimate outcrossing rates, inbreeding coefficients, and inbreeding depression among native, naturalized, and invasive populations of (Phrymaceae).

The mating system of non-native plant populations plays a role in determining the colonizing success following introduction into locations outside of the native distribution. For plant species capable of mixed-mating, both selfing and outcrossing can be advantageous and promote the establishment, persistence, and spread of newly arrived populations. To investigate how mating systems may contribute to the invasion process we estimated mating system parameters in perennial populations of the model plant species, from its native range (West coast USA), non-native populations that are established but have not become invasive (East coast USA, >50 years), and populations in invasive regions (UK >200 years).

Plasma phosphorylated tau181 outperforms [F] fluorodeoxyglucose positron emission tomography in the identification of early Alzheimer disease.

Background And Purpose: This study was undertaken to compare the performance of plasma p-tau181 with that of [F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the identification of early biological Alzheimer disease (AD).

Methods: We included 533 cognitively impaired participants from the Alzheimer's Disease Neuroimaging Initiative. Participants underwent PET scans, biofluid collection, and cognitive tests.