The exact mechanisms involved in cognitive impairment that occurs with AIDS is unclear. Neuropsychological testing is often performed to assess deficits, however, non-invasive measurements of cerebral blood flow may allow for detection of deficits prior to abnormal neuropsychological results. Early diagnosis and treatment may lead to improvement. CASL MRI is a non-invasive tool that follows tissue and microvasculature perfusion of arterial water. 32 HIV patients and 6 controls underwent neuropsychological evaluation and were rated on the HIV dementia scale by Power (10 asymptomatic, 14 MCD, 8 ADC). Patients had laboratory results (CD4+, viral load, hemoglobin, hematocrit) taken within 2 months of the scan. Images were obtained on a Siemens 3.0T scanner using a standard quadrature head coil and imaging protocol which includes an axial rapid gradient echo followed by a CASL perfusion sequence. Global resting perfusion (GRP) and resting perfusion (RP) within the perforating branches of arterial circulation wa...

Patterns of unique functional neural activations correlated with a motion detection paradigm can illustrate the implication of alternative pathways allowing residual vision following visual impairment. Individuals with a clinical blind hemifield, caused...

Although published paper atlases of the macaque brain provide accurate renderings of an individual animal, they lack the generalizability and ease of use of a multi-subject digital template based on Magnetic Resonance Imaging (MRI). The use of standardi...

Spinal cord injury (SCI) results in loss of voluntary motor control followed by incomplete recovery, which is partly mediated by the descending pathway from the primary motor cortex (M1). Human SCI study with magnetic resonance imaging (MRI) has reporte...

Introduction: Low back pain (LBP) is one of the leading causes of disability in the USA. Despite numerous magnetic resonance imaging (MRI) studies and investigative methods used, the pathophysiology of LBP in the brain remains unclear. Recent studies in...

We propose that the rate of increase of the brain concentration of sodium, [Na+]br, monitored using sodium MRI, can be used to locate the ischemic region in a rat model of cortical ischemia. In four Sprague-Dawley rats, focal cortical ischemia was induced during isoflurane anesthesia and continuous physiological monitoring. Sodium 3D and proton 2D data were acquired on a 3 Tesla whole body scanner (GEMS) using a dual tuned 5 cm diameter coil. [Na+]br time course maps were acquired continuously from 2-7 hr after occlusion. T2-weighted proton images (T2w, see Fig) and MAP2 immuno-stained brain sections were used to verify the location of the infarct (red outline). AMIDE software was used to view, analyze, and register image data, including a parametric image of the rate of [Na+]br increase (color scale). For all four animals the region of maximal [Na+]br increase corresponded to the ischemic region identified with MAP2. [Na+]br increased at a population mean rate of 19 ± 2.4 %/hr in ischemic tissue (p = 0.00...

Brain [Na+] has been proposed to assess insult duration in evolving stroke. Advances in sodium MRI make possible the measurement of the rate of [Na+] increase in a rat model of cortical ischemia. In five Sprague-Dawley rats (~400 g) focal cortical ischemia was induced with occlusion of the distal left middle cerebral artery and both common carotid arteries under isoflurane anesthesia. Sodium 3D data were acquired on a 3 T whole body scanner (GE MS), using a dual-tuned (23Na/1H), dual-quadrature birdcage RF coil. [Na+] maps (twisted projection) were acquired every 5.3 min from which the [Na+] in the ischemic and normal cortex was measured. The infarct was located using T2-weighted 1H images and immunoreactivity to MAP2 (HM2 ab, Sigma). The figure shows the time course of the [Na+] from the ischemic and normal cortex for one animal. [Na+] did not increase in normal cortex (0.02 ± 0.03 %/hr). In ischemic cortex, [Na+] increased at mean rate of 16 ± 3 %/hr (p < 0.001), comparing favorably with 23 ± 4 %/hr (n =...

White matter injury is a hallmark of traumatic brain injury (TBI) and diffusion-weighted (DW) magnetic resonance imaging (MRI) is most often the clinical research tool used to investigate this. In rodent experimental models of TBI, the analysis of such ...

Numerous studies have investigated how information about the position of a target object perceived through the senses is converted into motor commands, so that an effector can act toward this target. One of the challenges the brain faces in solving this task is the conversion of spatial coordinates

Neural activity that occurs during the creation of a new memory trace can be observed using functional magnetic resonance imaging (fMRI). Event-related designs have been used to demonstrate that activity in prefrontal and medial temporal lobe areas is associated with successful memory storage. Here we contrasted activity associated with encoding success and encoding effort. Participants viewed a series of 150 words but attempted to remember only half of them. Encoding effort was manipulated using a cue in the form of a letter (R or F) presented after each word to instruct participants either to remember or to forget that word. Increased activity in left inferior prefrontal cortex was observed when words were followed by the cue to remember. In contrast, increased left medial temporal lobe activity was observed for words that were successfully recalled later. These results show that fMRI correlates of the intention to encode a word are different from fMRI correlates of whether that encoding is successful. P...