Low soluble amyloid-β 42 is associated with smaller brain volume in Parkinson's disease.

Introduction: We sought to examine whether levels of soluble alpha-synuclein (α-syn), amyloid-beta (Aβ42), phosphorylated tau (p-tau), and total tau (t-tau), as measured in cerebrospinal fluid (CSF), are associated with changes in brain volume in Parkinson's disease.

Methods: We assessed the 4-year change in total brain volume (n = 99) and baseline CSF α-syn, Aβ42, p-tau, and t-tau of Parkinson Progression Markers Initiative participants. We used linear mixed models to assess the longitudinal effect of baseline CSF biomarkers on total and regional brain volume and thickness as well as linear regression for cross-sectional analyses at baseline and year 2.

Mnemonic Similarity Task to study episodic memory in Parkinson's disease.

Introduction: Parkinson's disease (PD) patients commonly experience episodic memory impairments, which are associated with an increased risk of dementia. The Mnemonic Similarity Task (MST) is a well-validated test to investigate episodic memory changes in healthy aging and in neurodegenerative diseases but has not been studied in PD patients.

Methods: In the MST task, participants respond during a testing phase whether visualized images are "repeat", "similar", or "new", compared to images previously shown during an encoding phase.

White Matter Hyperintensities Related to Parkinson's Disease Executive Function.

Background: People with Parkinson's disease (PD) can develop multidomain cognitive impairments; however, it is unclear whether different pathologies underlie domain-specific cognitive dysfunction.

Objectives: We investigated the contribution of vascular copathology severity and location, as measured by MRI white matter hyperintensities (WMHs), to domain-specific cognitive impairment in PD.

Methods: We studied 85 PD (66.

Dopamine D2 Receptors in Dopaminergic Neurons Modulate Performance in a Reversal Learning Task in Mice.

Neuroimaging studies in animal models and human subjects have each revealed that relatively low striatal dopamine D2-like receptor binding potential is associated with poor impulse control and with vulnerability for addiction-related behaviors. These studies cannot, however, disambiguate the roles for various pools of D2 receptors found in the striatum (e.g.