David J. Brooks

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BACKGROUND A consensus conference on multiple system atrophy (MSA) in 1998 established criteria for diagnosis that have been accepted widely. Since then, clinical, laboratory, neuropathologic, and imaging studies have advanced the field, requiring a fresh evaluation of diagnostic criteria. We held a second consensus conference in 2007 and present the(More)
We have used positron emission tomography to study the functional anatomy of motor sequence learning. Subjects learned sequences of keypresses by trial and error using auditory feedback. They were scanned with eyes closed under three conditions: at rest, while performing a sequence that was practiced before scanning until overlearned, and while learning new(More)
We investigated the functional anatomy of self-initiated and externally triggered movements. Six patients with Parkinson's disease off medication and six age-matched normals were assessed. All subjects had regional cerebral blood flow (rCBF) measurement with PET and recording of movement-related cortical potentials (MRPs) from frontal (F), fronto-central(More)
Event-related potential studies in man suggest a role for the supplementary motor area (SMA) in movement preparation, particularly when movements are internally generated. In a previous study combining PET with recording of movement-related cortical potentials, we found similar SMA activation and early pre-movement negativity during self-initiated and(More)
Selection of movement in normal subjects has been shown to involve the premotor, supplementary motor, anterior cingulate, posterior parietal, and dorsolateral prefrontal areas. In Parkinson's disease (PD), the primary pathological change is degeneration of the nigrostriatal dopaminergic projections, and this is associated with difficulty in initiating(More)
To identify cortical regions activated during saccades and visual fixation, regional cerebral blood flow (rCBF) was measured in eight healthy subjects using C15O2 PET during the performance of three tasks: (i) central fixation; (ii) reflexive saccades to random targets; (iii) remembered saccades to locations of recent target appearance. Significant rCBF(More)
We used positron emission tomography to study new learning and automatic performance in normal volunteers. Subjects learned sequences of eight finger movements by trial and error. In a previous experiment we showed that the prefrontal cortex was activated during new learning but not during during automatic performance. The aim of the present experiment was(More)
We used positron emission tomography to study motor learning by trial and error. Subjects learned sequences of eight finger movements. Tones generated by a computer told the subjects whether any particular move was correct or incorrect. A control condition was used in which the subjects generated moves, but there was no feedback to indicate success or(More)
Dopaminergic neurotransmission may be involved in learning, reinforcement of behaviour, attention, and sensorimotor integration. Binding of the radioligand 11C-labelled raclopride to dopamine D2 receptors is sensitive to levels of endogenous dopamine, which can be released by pharmacological challenge. Here we use 11C-labelled raclopride and positron(More)
1. Positron emission tomography (PET) studies were performed in six normal right-handed male volunteers (age 30 +/- 3) to investigate the relationship between cerebral activation as measured by relative regional cerebral blood flow (rCBF) and force peak exerted during right index finger flexion. The purpose was to determine in which central motor structures(More)