Although significant strides have been made using high-field fMRI to study brain activity in primates (e.g. Logothetis, 2003, 2002), many of these studies have employed anesthesia and paralytics which can significantly affect the BOLD response (Leopold et al., 2002). To better approximate the conditions under which human data is collected and to conduct oculomotor studies, we have recently developed techniques to acquire fMRI data at 4.7T using alert, behaving rhesus monkeys. To optimize ergonomics, a 60-cm bore, vertically oriented, superconducting magnet (Magnex) with a Varian console is used. Head stabilization is achieved through a stereotaxically-placed, polyetheretherketon superstructure attached to the skull with MRI-compatible ceramic screws. Monkeys are trained to fixate and/or track targets on a visual display system (Avotec) while the position of each eye is monitored (SensorMotoric Instruments). A successive approximation training schedule is then used to acclimate the animals to the environmen...

Introduction. Epilepsy is a brain disorder characterized by seizures affecting approximately 1-2% of children worldwide, and is associated with significant medical, psychological, and social burdens. Magnetic resonance imaging (MRI)-guided laser-induced...

Corticotropin-releasing factor (CRF) is a neuromodulator of brain functions such as learning and anxiety, and is involved in several psychiatric disorders. Targeting CRF binding sites with spatial and temporal resolution by using magnetic resonance imaging (MRI) would greatly facilitate research on the CRF system. Therefore, we synthesized and pharmacologically characterized a CRF analog labeled with gadolinium, the contrast agent most commonly used in MRI. The chelator DOTA was coupled to the N-terminus of human/rat CRF (h/rCRF) under standard solid phase peptide synthesis conditions. The obtained DOTA-h/rCRF was purified and loaded with gadolinium (Gd) in a reaction monitored with mass spectrometry. After purification, Gd-DOTA-h/rCRF was tested for its pharmacological properties using transfected human embryonic kidney (HEK) 293 cells producing either rat CRF receptor (CRFR) 1, mouse CRFR2β or rat CRF binding protein (CRFBP). The affinities of Gd-DOTA-h/rCRF to rat CRFR1 (IC50 = 4.5 nM) and mouse CRFR2β ...

Background: With the advent of diffusion magnetic resonance imaging (MRI) technology and analysis, recent work has evaluated the clinical utility of white matter tract imaging in the preoperative planning strategy to localize targets for deep brain stim...

Lysergic acid diethylamide (LSD) is a potent drug that produces distorted perceptions, disorganized thought, and altered mood in humans. At present, the neuronal substrates mediating these effects are poorly understood. In this study, we used functional magnetic resonance imaging (fMRI) to evaluate LSD-induced blood oxygen level dependent (BOLD) response in rat brain. Briefly, rats (n=3) were anesthetized with isoflurane (1%), paralyzed with pancuronium (0.5 mg/kg, i.p.), artificially ventilated (50 breaths/min, tidal volume of 3 ml), and placed in a Varian 9.4 Tesla MRI instrument. After collecting basal volume data sets for 20 min, rats received LSD (500 µg/kg, i.p.) and volume data sets were collected for 40 min post drug. Mean voxel values averaged across a 5 min period prior to and 25-30 min after LSD administration were compared using Student's t-test (significance level set at p < 0.001). Anatomical localization of the BOLD signal was determined by using a rat brain atlas template (Paxinos and Watso...

Visualization is a critical component in neuroscientific investigation, enabling researchers to intuitively understand and meaningfully navigate complex data. This is becoming even more crucial as methodologies such as magnetic resonance imaging (MRI) a...

Magnetic resonance imaging (MRI) in humans with unilateral superior oblique (SO) palsy indicates presumably compensatory hypertrophy of some rectus extraocular muscles (EOMs), including the ipsilesional lateral rectus (LR) and inferior rectus (IR), and ...

Voxel-based morphometry (VBM) is widely used in research and diagnosis of neurodegenerative diseases, such as Alzheimer's disease (AD). High quality magnetic resonance imaging (MRI) and conscientious data preprocessing is necessary for reliable results....

Age-related loss of brain tissue has been inferred from cross-sectional neuroimaging studies, but direct measurements of gray and white matter changes from longitudinal studies are lacking. We quantified longitudinal magnetic resonance imaging (MRI) scans of 92 nondemented older adults (age 59–85 years at baseline) in the Baltimore Longitudinal Study of Aging to determine the rates and regional distribution of gray and white matter tissue loss in older adults. Using images from baseline, 2 year, and 4 year follow-up, we found significant age changes in gray ( p < 0.001) and white ( p < 0.001) volumes even in a subgroup of 24 very healthy elderly. Annual rates of tissue loss were 5.4 ± 0.3, 2.4 ± 0.4, and 3.1 ± 0.4 cm3 per year for total brain, gray, and white volumes, respectively, and ventricles increased by 1.4 ± 0.1 cm3 per year (3.7, 1.3, 2.4, and 1.2 cm3, respectively, in very healthy). Frontal and parietal, compared with temporal and occipital, lobar regions showed greater decline. Gray matter loss w...

Translational studies of rodent brains have been and will continue to be crucial to characterizing the aging human brain. Magnetic Resonance Imaging (MRI) can quantitatively measure anatomy, connectivity and microstructure in both human and rodent brain...