Over 1.5 million cases of TBI are reported annually in the U.S., yet reliable tools for prognosis of persistent symptoms following mild TBI are elusive. Diffuse Axonal Injury (DAI) is the most common form of damage, yet current MRI techniques cannot quantify DAI, limiting prognosis and treatment. We present a method to quantitatively evaluate the integrity of white matter tracks reproducibly. The Reproducible Objective Quantification Scheme (ROQS) presents guidelines for selection of 15 reproducible Regions of Interest (ROI) based on anatomically identifiable structures. These ROI are applied to Diffusion Tensor Imaging (DTI) to provide estimates of anisotropy indices and diffusion coefficients. This same method is also applied to Magnetization Transfer Imaging (MTI), which provides a normalized measure (MT Ratio) of the amount of signal suppression that correlates to the type of matter being imaged. Normal volunteers (n=25) were imaged using DTI and MTI to establish population parameters for each ROI. Int...

Introduction: Rapid progress in the development of real time MRI imaging of specific nerve projections in the CNS has been made in the last few years. Of particular interest has been the demonstration of MnCl2 as an MRI contrast agent enabling visualisation of specific axonal pathways in the nervous system. We report here for the first time in vivo transynaptic transport of MnCL2 in the visual system of rats demonstrated with MRI. Materials and Methods: Adult inbred Fisher rats (n=4) were subjected to unilateral intravitreal injection of 2 ul of 100 mM MnCl2 with all procedures in accordance to national local authority regulations. MRI was performed at 2.35 T using a Bruker Biospec Avance DBX-100 (Bruker AG, Germany), with a 72 mm volume coil for transmission and an actively decoupled quadrature rat head surface coil for receive-only. Water-cooled BGA-12 (200 mT/m) gradients were used. The MRI protocol was according to Brekken et al. 2003. Results: MRI performed 36 hours post-injection demonstrated specifi...

Advances in functional imaging have allowed to investigate neuroanatomical correlates of sexual arousal (SA) in a noninvasive manner. Objective: To identify the neuroanatomical correlates of SA of healthy men presented with sexually stimulating photographs. Methods: in ten healthy men, functional magnetic resonance imaging was used to study brain responses to the presentation of highly arousing and of nonsexually arousing photographs representing women. Immediately after the fMRI run, rating scales were presented to subjects to assess perceived SA. Volumetric penile plethysmography was performed during scans. Results: both rating scales and plethysmography demonstrated SA in response to sexually stimulating photographs. Regions that were more activated in response to the sexually arousing than to the neutral photographs included bilaterally the fusiform gyri, the inferior occipital gyri, the superior and the inferior parietal lobules, the thalami, the right precentral gyrus, the left caudate body, the righ...

The complex environment we live in makes it necessary to distinguish relevant from irrelevant information constantly and reliably. The aim of the present study was to investigate the neural substrate underlying the selection of task-relevant information. We devised a new paradigm in which participants had to switch between two different tasks that were instructed by task cues. The task cues had a relevant and an irrelevant cue dimension. In congruent trials, both cue dimensions indicated the same task; in incongruent trials, they indicated different tasks; and in neutral trials, only the relevant dimension indicated a task. By comparing trials in which both cue dimensions were informative (congruent and incongruent trials) with trials in which only the relevant dimension was informative (neutral trials), we were able to show that the lateral prefrontal cortex and a region in the intraparietal sulcus are involved in the selection of task-relevant information. Furthermore, the present paradigm allows the inf...

Heart failure patients (HF) exhibit deficient heart rate variability patterns during sleep, inappropriate blood pressure responses to evoked challenges, and sleep-disordered breathing patterns, suggesting central regulatory disturbances of autonomic and respiratory control. We examined signal changes in neural sites recruited during a cold pressor challenge to the forehead. A series of 20 image slices (25 volumes, Echo Planar technique) through the brain of 5 HF patients (32-59 yrs), all with sleep-disordered breathing, and 20 healthy control subjects (29-66 yrs) was collected during 1 min baseline and 1.5 min application of a bag of cold (3°C) deuterium oxide to the forehead in a GE 1.5T Signa scanner. Images collected during baseline and challenge conditions were spatially normalized and subjected to a random-effects analysis using the SPM imaging package. Signal changes were significantly diminished in paravermal cerebellar and hippocampal areas of HF patients over controls. We speculate that cerebellar...

Humans are endowed with a natural sense of fairness that permeates social perceptions and interactions. This moral stance is so ubiquitous that we may not notice it as a fundamental component of daily decision making and in the workings of many legal, political, and social systems. Emotion plays a pivotal role in moral experience by assigning human values to events, objects, and actions. Although the brain correlates of basic emotions have been explored, the neural organization of “moral emotions” in the human brain remains poorly understood. Using functional magnetic resonance imaging and a passive visual task, we show that both basic and moral emotions activate the amygdala, thalamus, and upper midbrain. The orbital and medial prefrontal cortex and the superior temporal sulcus are also recruited by viewing scenes evocative of moral emotions. Our results indicate that the orbital and medial sectors of the prefrontal cortex and the superior temporal sulcus region, which are critical regions for social beha...

In this study we were interested in the hypothesis that different task sets would influence both behavior and prefrontal cortex (PFC) activation during performance of a memory task. Specifically, participants were asked to remember a list of words over a short delay, and then respond to a probe word, indicating whether or not the probe was present in the list of words. In one condition, participants were encouraged to use an active maintenance strategy by presenting short lists of words (1 to 6 words per list). In the other condition, participants were encouraged to use a retrieval-based strategy by presenting long lists of words (6 to 11 words per list). The critical comparison is between the 6-word trials, since the memory load, trial duration, and perceptual input are identical across the two conditions. To test our hypothesis that activation in PFC would correlate with task set, we conducted an event-related functional magnetic resonance imaging (fMRI) study on 25 younger adults. Behavioral results con...

Although transient airway constrictions occur during sleep both in normal and obstructive sleep apnea (OSA) subjects, neural mechanisms that maintain upper airway patency appear not to be activated, or are recruited with sufficient delay to be ineffective in OSA patients. To evaluate these mechanisms, a series of 20 image slices (25 repetitions, Echo Planar technique) through the entire brain was collected during 1 min baseline and 1.5 min expiratory (8 controls, 12 OSA) and inspiratory (10 Controls, 6 OSA) loading challenges in a GE 1.5T Signa scanner. Ages of Controls were 29-62; OSA ages were 29-66. Images were subjected to fixed effects analysis using the SPM imaging package. Areas recruited in both control and patient groups included deep cerebellar nuclei, putamen, and hippocampus. The OSA group showed significantly more dispersion of areas with signal changes, including the orbital frontal cortex, multiple cerebellar regions, and widespread diencephalic sites. In certain forebrain areas, a delayed o...

Functional magnetic resonance imaging (fMRI) was used to monitor spinal cord mediated activation of sensory motor cortex by measuring changes of blood oxygenation level-dependent (BOLD) contrast during electric stimulation of forepaw, hindpaw or tail. Single or multi-slice gradient echo images were collected using gradient echo fast imaging or spiral gradient imaging. Stimulation of fore- or hindpaws repeatedly lead to robust activation of contralateral sensorimotor cortex. The center of the main cortical representation was situated 3.4 mm lateral to the midline and 5 mm posterior to the rhinal fissure (prf) for the forepaw and 2.0 mm lateral to the midline and 6 mm prf for the hindpaw. Tail stimulation gave rise to an extended bilateral cortical activation, along the midline in medial frontal and cingulate gyrus 4 and 5 mm prf. Axonal regeneration in peripheral nerves has been obtained using degradable tubes made of polyglycolic acid (PGA) and collagen (Kiyotani et al., 1996 Brain Res, 740:66-74). To obta...

Childhood sexual abuse is a major public health problem, however little is known about the effects of abuse on brain structure or function. Animal studies have shown that stressors similar to childhood abuse result in damage to the hippocampus, a brain area involved in learning and memory, and our group and others have reported smaller hippocampal volume measured with magnetic resonance imaging (MRI) and deficits in hippocampal-based verbal declarative memory (recall of a paragraph) in patients with abuse-related PTSD. The purpose of this study was to compare hippocampal volume measured with MRI and hippocampal function during declarative memory tasks (encoding of a paragraph) measured with positron emission tomography (PET), in 33 women, including women with early childhood sexual abuse and PTSD, women with early abuse without PTSD, and women without early abuse or PTSD. A failure of left hippocampal activation during memory tasks was seen in PTSD relative to abused non-PTSD women (F=14.94; df=1,20; p<.00...