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Intersensory temporal synchrony is an ubiquitous sensory attribute that has proven to be critical for binding multisensory inputs, sometimes erroneously leading to dramatic perceptual illusions. However, little is known about how the brain detects temporal synchrony between multimodal sensory inputs. We used positron emission tomography to demonstrate that(More)
Long-term deprivation of visual input for several days or weeks leads to marked changes in the excitability and function of the occipital cortex. The time course of these changes is poorly understood. In this study, we addressed the question whether a short period of light deprivation (minutes to a few hours) can elicit such changes in humans. Noninvasive(More)
Although the importance of the posterior parietal and prefrontal regions in spatial localization of visual stimuli is well established, their role in auditory space perception is less clear. Using positron emission tomography (PET) during auditory and visual spatial localization in the same subjects, modality-specific areas were identified in the superior(More)
Clinical recovery after stroke can be significant and has been attributed to plastic reorganization and recruitment of novel areas previously not engaged in a given task. As equivocal results have been reported in studies using single imaging or electrophysiological methods, here we applied an integrative multimodal approach to a group of well-recovered(More)
Little is known about how the brain binds together signals from multiple sensory modalities to produce unified percepts of objects and events in the external world. Using event-related functional magnetic resonance imaging (fMRI) in humans, we measured transient brain responses to auditory/visual binding, as evidenced by a sound-induced change in visual(More)
To learn more about human auditory spatial processing, we used positron emission tomography (PET) to measure regional cerebral blood flow in human volunteers engaged in sound localization tasks. Spectral and binaural cues of localized sound were reproduced by a sound system and delivered via headphones. During localization tasks, subjects activated inferior(More)
Constraint-induced movement therapy (CI), a standardized intensive rehabilitation intervention, was given to patients a year or more following stroke. The goal was to determine if CI was more effective than a less-intensive control intervention in changing motor function and/or brain physiology and to gain insight into the mechanisms underlying this(More)
Functional imaging studies of the cerebellum have mostly investigated motor performance or have been limited to the anterior lobe and therefore the somatosensory representations in the human cerebellum have not been fully demonstrated. We used fMRI of the entire cerebellum during tactile stimulation of the hand and foot in six normal subjects. Our results(More)
Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by ataxia of all four limbs, dysarthria, and arreflexia. A variety of measures are currently used to quantify disease progression, including the Friedreich Ataxia Rating Scale, examiner-rated functional disability scales, self-reported activities of daily living and(More)
Hereditary and sporadic neurodegenerative ataxias are movement disorders that affect the cerebellum. Robust and objective biomarkers are critical for treatment trials of ataxias. In addition, such biomarkers may help discriminate between ataxia subtypes because these diseases display substantial overlap in clinical presentation and conventional MRI.(More)