Cognition following bilateral deep brain stimulation surgery of the subthalamic nucleus for Parkinson's disease.

Objective: Parkinson's disease (PD) is a neurodegenerative disorder characterized by significant motor dysfunction and various non-motor disturbances, including cognitive alterations. Deep brain stimulation (DBS) is an increasingly utilized therapeutic option for patients with PD that yields remarkable success in alleviating disabling motor symptoms. DBS has additionally been associated with changes in cognition, yet the evidence is not consistent across studies.

Decision-making capacity and competency in the elderly: a clinical and neuropsychological perspective.

With our ageing population, the number of older adults with cognitive impairment has also increased. There is both an acute and growing need for evidence-based assessments to identify their decision making capacity and competence. In the present article we (1) present definitions of decision-making capacity and competence, (2) review cognitive functions that are central to decision-making capacity as well as the methods and procedures commonly used to assess these domains, and (3) address the communication of assessment findings to patients and their loved ones.

Phenylthiocarbamide (PTC) perception in Parkinson disease.

Objective: To examine phenylthiocarbamide (PTC) sensitivity in Parkinson disease (PD) patients and healthy volunteers to determine whether taster status represented a simple vulnerability marker for PD.

Background: The inability to taste PTC has been associated with a number of medical illnesses not typically associated with taste impairment. Abnormalities in the function/expression of G protein-signaling pathways have been implicated in PTC perception and also in dopamine expression and regulation in PD.

Dopamine receptor blockade and extinction differentially affect behavioral variability.

Dopamine (DA) neurons respond to unexpected food delivery and are inhibited during the omission of expected reward. DA receptor blockade mimics some, but not all, aspects of non-reward (extinction) conditions. It was therefore of interest to ask whether DA receptor blockade produces extinction-like increases in behavioral variability in addition to its well-known operant response-suppressing effects.