Leonora Wilkinson

Learn More
Normal actions and behaviors often require inhibition of unwanted and inadequate movements. Motor inhibition has been studied using the stop signal task, in which participants are instructed to respond to a go signal. Sporadically, a stop signal is also delivered after a short interval following the go signal, prompting participants to inhibit their already(More)
Sequence knowledge acquired by repeated exposure to targets in a speeded localization task was studied in 3 experiments that sought to test A. Destrebecqz and A. Cleeremans's (2001, 2003) claim that, under certain circumstances, the expression of such sequence knowledge cannot be brought under intentional control. In Experiment 1 participants were trained(More)
Previous studies indicate that a variety of pharmacological agents interfere with the prepulse inhibition of the acoustic startle (PPI) response including phencyclidine (PCP), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), amphetamine, and apomorphine. Strain differences have been observed in the ability of apomorphine to disrupt PPI, although the(More)
In Parkinson's disease (PD), it is possible that tonic increase of dopamine associated with levodopa medication overshadows phasic release of dopamine, which is essential for learning. Thus while the motor symptoms of PD are improved with levodopa medication, learning would be disrupted. To test this hypothesis, we investigated the effect of levodopa(More)
In vivo dialysis coupled to high-performance liquid chromatography with electrochemical detection (HPLC-EC) was used for measurement of extracellular serotonin (5-HT) in the hypothalamus of unanesthetized, unrestrained rats. A series of experiments was carried out to determine if 5-HT in the dialysis solution was released from nerve terminals. Fenfluramine,(More)
Evidence from animal, clinical, and imaging studies suggests that the basal ganglia and their frontal connections mediate motor inhibition, but the role of dopamine remains unclear. The aim of our study was to investigate, for the first time, whether levodopa medication influences motor inhibition and conflict resolution on the conditional stop-signal(More)
The frontal assessment battery (FAB) is a bedside test of executive function. It takes less than 10 minutes to administer and a low score indicates executive dysfunction. To determine whether the FAB could detect the more severe subcortical dementia that is a feature of PSP and differentiate it from other bradykinetic rigid syndromes, we studied 17 patients(More)
Eleven patients with active unicameral bone cysts were treated primarily with placement of demineralized bone matrix in the cyst by using a two-needle technique and a custom large-bore needle. Cyst healing was rated according to the Neer classification, and the average time of healing was 4.5 months. The demineralized bone matrix demonstrated an ability to(More)
Recent imaging studies in healthy controls with a conditional stop signal reaction time (RT) task have implicated the subthalamic nucleus (STN) in response inhibition and the pre-supplementary motor area (pre-SMA) in conflict resolution. Parkinson’s disease (PD) is characterized by striatal dopamine deficiency and overactivity of the STN and underactivation(More)
The distinction between implicit (unconscious) and explicit (conscious) learning is controversial. Some argue that explicit learning is dependent on the medial temporal lobes, whereas implicit learning is mediated by the basal ganglia and others propose that all learning is explicit. The purpose of the present study was to investigate the involvement of the(More)