Ashleigh Hillier

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Stress-induced activation of the locus ceruleus-norepinephrine (LC-NE) system produces significant cognitive and behavioral effects, including enhanced arousal and attention. Improvements in discrimination task performance and memory have been attributed to this stress response. In contrast, for other cognitive functions that require cognitive flexibility,(More)
OBJECTIVES Our purpose is to investigate cognitive performance and extrapyramidal function early after ecstasy use. BACKGROUND Ecstasy, containing 3,4 methylenedioxymethamphetamine, has shown evidence of causing cognitive deficits and parkinsonian signs. Previous research has examined cognitive performance after a period of prolonged abstinence, but(More)
Previous research suggests that the noradrenergic system modulates certain types of cognitive flexibility. This study compared various doses of beta-adrenergic antagonists for their effect on cognitive flexibility in problem solving, and how task difficulty interacts with this effect, as well as the effect of beta-adrenergic antagonists on other tasks.(More)
OBJECTIVE Our purpose was to study the effect of semantic priming at varying semantic distances on brain activation during a lexical decision experiment, using functional magnetic resonance imaging (fMRI). BACKGROUND Neuroimaging studies have demonstrated decreased brain activation for primed versus unprimed stimuli in language areas due to semantic(More)
BACKGROUND The noradrenergic system modulates cognitive flexibility for insight-based problem solving in studies using beta-adrenergic antagonists, which block noradrenergic neurotransmission postsynaptically. However, it is not known whether alpha2-adrenergic agonists, that decrease noradrenergic neurotransmission by presynaptic inhibition, have the same(More)
The noradrenergic system modulates performance on tasks dependent on semantic and associative network flexibility (NF) in individuals without neurodevelopmental diagnoses in experiments using a beta-adrenergic antagonist, propranolol. Some studies suggest drugs decreasing noradrenergic activity are beneficial in ASD. In individuals without(More)
Individuals with autism spectrum disorders (ASD) demonstrate impaired utilization of context, which allows for superior performance on the "false memory" task. We report the application of a simplified parallel distributed processing model of context utilization to the false memory task. For individuals without ASD, experiments support a model wherein(More)
Previous research suggests that the noradrenergic system modulates flexibility of access to the lexical-semantic network, with propranolol benefiting normal subjects in lexical-semantic problem solving tasks. Patients with Broca's aphasia with anomia have impaired ability to access appropriate verbal output for a given visual stimulus in a naming task.(More)
We describe an fMRI experiment examining the functional connectivity (FC) between regions of the brain associated with semantic and phonological processing. We wished to explore whether L-Dopa administration affects the interaction between language network components in semantic and phonological categorization tasks, as revealed by FC. We hypothesized that(More)
Individuals with autism spectrum disorders (ASD) have been shown in some studies to be less susceptible to the verbal "false memory" effect, perhaps due to restricted semantic associative networks. High-functioning individuals with ASD can demonstrate subtle language impairments. However, relative preservation of spatial skills can also be observed. This(More)