Track topics on Twitter Track topics that are important to you
This study will explore how the areas in the brain are connected to link what people see to what they do; that is, how they use what they see to help guide their movements. The study uses functional magnetic resonance imaging (fMRI) to look at different areas in the brain while a person performs tasks in which both what they see (visual input) and what they do (their motor response) are related or unrelated.
Healthy, right-handed normal volunteers who are 18 years of age or older may be eligible for this study. Candidates are screened with a medical history, neurological examination and MRI scan, if one has not been done within a year of entering the study. MRI uses a magnetic field and radio waves to produce images of body tissues and organs. The subject lies on a table that can slide in and out of the scanner (a narrow cylinder), wearing earplugs to muffle loud knocking sounds that occur during scanning. The procedure lasts about 90 minutes, during which the subject is asked to lie still for up to 30 minutes at a time.
Participants undergo fMRI for this 1-day study. fMRI differs from ordinary MRI in that the subject performs tasks during the scanning, allowing researchers to see brain changes that occur during performance of the activity. Before the scan, the subject is trained for the tasks, which include looking at shapes while following them with the fingers and looking at shapes without making finger movements. Following the testing, subjects have a second ordinary MRI scan.
The purpose is to analyze task-related connectivity changes in brain regions, using a block design blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI), as a function of the linkage between visual input and motor output.
- 25 right-hand dominant, healthy adult volunteers
Connectivity between brain areas can change related to the dependence level between visual input and motor output. The dependence level will be modulated while performed tasks engage visual and motor areas either in a functionally related fashion or not. Subjects will perform a visuomotor task (VM, dependence level = maximal) that consists of tracking a target by exerting force isometrically on a transducer with their right index finger (target signal and exerted force are displayed in the scanner). In the visual plus motor task (V+M), two different tasks will be performed simultaneously. Subjects will perform the same motor task as in VM but without target signal and visual feedback of their force control, while a neutral visual input unrelated to the motor output is dynamically flashed in the screen. In the visual (V), subjects will watch the target signal while relaxed. In the motor task (M), subjects will produce the same motor task as in VM and V+M while staring at a static fixation cross. A rest period will require subjects to fixate on a stationary dot in the middle of the visual field. fMRI scanning will be used to record brain activity during tasks.
The experimental phase will have six sets of 6-minute scanning sessions where the subject will perform the conditions. The conditions will appear pseudo-randomly throughout the scan sessions. V will always precede VM condition to avoid motor system activation secondary to imagination of movement primed by the visual stimulus. The M and VM conditions will be presented in a random order. At the completion of fMRI scanning, a baseline high-resolution MRI T1 scan will be obtained for anatomic localization and co-registration.
The primary outcome is the connectivity change in brain networks in response to loss of dependence between a sensory input and the motor output. We will be focused on the correlation between the time series of activations in each condition and the connectivity changes over all the conditions. This will allow us to elucidate the task-dependent connectivity between occipital cortex and prefrontal cortex relative to the functional link between visual input and motor output.
National Institutes of Health Clinical Center, 9000 Rockville Pike
National Institutes of Health Clinical Center (CC)
Published on BioPortfolio: 2014-08-27T03:42:33-0400
In blind individuals, the occipital cortex becomes capable of processing tactile and auditory information, a phenomenon described as crossmodal plasticity. GABA is the major inhibitory ne...
This study will compare the analgesic benefit of a traditional landmark-guided GON block with the ultrasound-guided approach over a four week period in patients with occipital neuralgia or...
Medically intractable pain caused by occipital neuralgia can be very difficult to control with traditional pain management. Peripheral nerve stimulation which is used in migraines and clus...
This study evaluates the effect in chronic migraine patients of daily 20 minute-transcutaneous sub occipital neurostimulation using the occipital Cefaly° device.
We are comparing a type of nerve block called greater occipital nerve block versus standard therapy among patients who present to an emergency department for acute migraine. This is a rand...
PET using FDG is a critical tool for evaluation of dementias, with characteristic patterns of hypometabolism suggesting specific diagnoses. Hypometabolism in the occipital region is recognized as an i...
Despite the widespread use of steady-state visual evoked potentials (SSVEPs) elicited by luminance flicker in clinical and research settings, their spatial and temporal representation in the occipital...
The comparative analysis of the endocranial surface of the El Sidrón new occipital fragment SD-2300 shows meaningful differences in the configuration of the occipital pole region between neandertals ...
In the literature, there are few reports that provide a detailed account on the technique of visual electrocortical stimulation in the setting of resective surgery for occipital epilepsy. In this tech...
Although pathologic vascular contact between the occipital artery and the greater occipital nerve (GON) at the crossing point in the nuchal subcutaneous layer can cause occipital neuralgia, referred h...
Area of the occipital lobe concerned with vision.
The inability to recognize a familiar face or to learn to recognize new faces. This visual agnosia is most often associated with lesions involving the junctional regions between the temporal and occipital lobes. The majority of cases are associated with bilateral lesions, however unilateral damage to the right occipito-temporal cortex has also been associated with this condition. (From Cortex 1995 Jun;31(2):317-29)
A composite area of the cerebral cortex concerned with motor control and sensory perception comprising the motor cortex areas, the somatosensory areas, the gustatory cortex, the olfactory areas, the auditory cortex, and the visual cortex.
The point of articulation between the OCCIPITAL BONE and the CERVICAL ATLAS.
Loss of the power to comprehend written materials despite preservation of the ability to write (i.e., alexia without agraphia). This condition is generally attributed to lesions that "disconnect" the visual cortex of the non-dominant hemisphere from language centers in the dominant hemisphere. This may occur when a dominant visual cortex injury is combined with underlying white matter lesions that involve crossing fibers from the occipital lobe of the opposite hemisphere. (From Adams et al., Principles of Neurology, 6th ed, p483)
Of all the types of Dementia, Alzheimer's disease is the most common, affecting around 465,000 people in the UK. Neurons in the brain die, becuase 'plaques' and 'tangles' (mis-folded proteins) form in the brain. People with Al...
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...
Radiology is the branch of medicine that studies imaging of the body; X-ray (basic, angiography, barium swallows), ultrasound, MRI, CT and PET. These imaging techniques can be used to diagnose, but also to treat a range of conditions, by allowing visuali...