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The supplementary motor complex consists of the supplementary motor area, the supplementary eye field and the pre-supplementary motor area. In recent years, these areas have come under increasing scrutiny from cognitive neuroscientists, motor physiologists and clinicians because they seem to be crucial for linking cognition to action. However, theories(More)
BACKGROUND Huntington's disease (HD) is an autosomal dominant, fully penetrant, neurodegenerative disease that most commonly affects adults in mid-life. Our aim was to identify sensitive and reliable biomarkers in premanifest carriers of mutated HTT and in individuals with early HD that could provide essential methodology for the assessment of therapeutic(More)
Visual neglect of left space following right parietal damage in humans involves a lateral bias in attention, apparent in many search tasks. We hypothesized that parietal neglect may also involve a failure to remember which locations have already been examined during visual search: an impairment in retaining searched locations across saccades. Using a new(More)
When we identify a visual object such as a word or letter, our ability to detect a second object is impaired if it appears within 400ms of the first. This phenomenon has been termed the attentional blink or dwell time and is a measure of our ability to allocate attention over time (temporal attention). Patients with unilateral visual neglect are unaware of(More)
The exact role of the parietal lobe in spatial cognition is controversial. One influential hypothesis proposes that it subserves spatial perception, whereas other accounts suggest that its primary role is to direct spatial movement. For humans, it has been suggested that these functions may be divided between inferior and superior parietal lobes,(More)
Saccades are rapid eye movements that move the line of sight between successive points of fixation; they are among the best understood of movements, possessing dynamic properties that are easily measured. Saccades have become a popular means to study motor control, cognition and memory, and are often used in conjunction with techniques such as functional(More)
Twelve patients with focal damage of the frontal cortex and 12 patients with mild, medicated, early stage Parkinson's disease switched between letter- and digit=naming tasks on every second trial of a task-switching paradigm. Compared with age- and IQ-matched control performance, patients with left-sided, but not right-sided, frontal damage exhibited(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)
Within the medial frontal cortex, the supplementary eye field (SEF), supplementary motor area (SMA), and pre-SMA have been implicated in the control of voluntary action, especially during motor sequences or tasks involving rapid choices between competing response plans. However, the precise roles of these areas remain controversial. Here, we study two(More)
OBJECTIVES We describe a novel rehabilitation tool for patients with homonymous hemianopia based on a visual search (VS) paradigm that is portable, inexpensive, and easy to deploy. We hypothesised that by training patients to improve the efficiency of eye movements made in their blind field their disability would be alleviated. METHODS Twenty nine(More)