Boundaries of specific gyri are often ambiguous, even on postmortem examination. This study addressed the reliability of MRI measurement between two labs using different methodologies for one frequently studied region, the planum temporale (PT). Scans were obtained for 40 normal men, aged 18-35 yr, who also had cognitive testing. The whole brain was scanned in 1.3 mm contiguous slices using a 1.5T MR imager (GE). The length of the horizontal segment of PT (HPT) was measured, extending from Heschl's main transverse sulcus (point H) to the point of posterior bifurcation of the Sylvian fissure (SF) or the end of the SF (point B). Both labs studied the same set of 40 scans and used the same definition of HPT (Witelson & Kigar, JCN, 1992). Lab 1 used all relevant slices in 3 planes, to locate the x, y, and z coordinates of points H and B and obtained the distance of HB. Lab 2 obtained the length of the tracing of the exposed surface of HB on sagittal slices (as in Leonard et al., Arch Neurol, 1993). Both labs o...

INTRODUCTION: So far fMRI could not be used to study functional reorganisation in rodent brain due to a lack of a paradigm for the motor system. In humans passive movement activates the motor cortex(1). We studied whether passive forepaw movement in the rat causes significant fMRI signal changes. METHODS: Seven rats were anaesthetized with alpha-chloralose. For perfusion weighted imaging (PWI) we used arterial spin tagging on a 4,7T MR-tomograph(2). Passive forepaw movement of the right wrist and elbow was induced with a frequency of 1,5Hz and an amplitude of 90° using a hydraulic pump. Electrical stimulation of the left forepaw was performed for comparison(2). Each experiment consisted of 50 perfusion weighted images during which passive movement (n=31) or electrical stimulation (n=24) were applied (off-on-off-on-off). RESULTS: During passive forepaw movement we observed in 4 of 7 rats and 13 of 31 experiments significant signal changes on PWI, which were located within the left sensory-motor cortex (t-te...

Introduction: The use of manganese chloride as a contrast agent for visualizing specific axonal projections with MRI is currently a topic under intense investigation. We demonstrate here the use of this technique to visualize normal and lesioned optic nerve in adult frog and fish. Materials and Methods: Adult frogs (rana pipiens, n=5) and adult fish (brown trout, n=5) were subjected to unilateral optic nerve transection followed by ipsilateral intravitreal injection of 2 ul of 100 mM manganese chloride. Normal control animals (n=3) underwent unilateral intravitreal injections of 2 ul of 100 mM of manganese chloride. All procedures were in accordance with national and local authority regulations. MRI was performed at 2.35 T using a Bruker Biospec Avance DBX-100 (Bruker AG, Germany) in accordance with a modified protocol by Brekken et al. 2003. Results: MRI performed at 48-72 hours post-injection demonstrated specific contrast uptake and transport in vivo throughout the visual system of both frog and fish. F...

INTRODUCTION: The severity of pathological protein deposition, and concomitant iron presence distinguishes neurological disorders. Tissues with high amounts of protein or iron deposits have a characteristically rapid T2* MRI signal decay. Therefore, the...

Objective: The NIH MRI Study of Normal Brain Development is being carried out by the “Brain Development Cooperative Group”. One primary goal of this multi-site study is to enroll a large sample of healthy infants, children and adolescents representative of the demographic characteristics of the U.S. population in order to establish healthy, regionally specific, brain development growth curves and to establish a MRI repository database of healthy subjects . The project is funded by NIH (NIMH, NICHD, NINDS, and NIDA). Methods: This report focuses on the recruitment, screening and cognitive/behavioral assessment related to Objective –1, which covers children from 4.5 to 18 years. Obj. 1 has completed the baseline subject enrollment, screening and scanning. Longitudinal follow up at 24 mo. intervals are planned. An epidemiological sampling frame was employed to recruit and screen. This strategy strives to minimizes biases present in samples of convenience. Targeted recruitment was based on zip code based U.S. ...

The present study evaluates the contribution of the thalamus to cognition using structural MRI-based volumetry in combination with neurocognitive testing of healthy subjects, Korsakoff's (KS) and Alzheimer's (AD) patients. Fifty-seven healthy subjects ranging from 21 to 82 years old were included. It could be shown that a highly significant decrease in thalamic volume occurred with higher age, stronger than and independent of total brain volume (r=-0.599, p=0.000). In young, but not in middle-aged or old subjects, thalamic volume was related to speeded information processing. This was evident from performance on the Stroop test, a memory scanning task and a variant of the trail making task. No relationship was found with higher cognitive functions such as semantic or episodic memory. Thalamic volumes of KS patients were smaller than those of healthy controls and non-KS alcoholics. Similarly, AD patients showed reductions in thalamic volume as compared to both healthy subjects and age-associated cognitive d...

Transient fetal subplate zone (SP) consists of loosely arranged axons, postmigratory and migratory neurons, growth cones, synapses and glia (Kostovic & Rakic, J Comp Neurol 297:441, 1990). The developmental peak of SP occurs during the sequential ingrowth of major cortical afferent fibre systems when SP serves as a waiting compartment. To explore the potential of MRI technique for in vivo imaging of the SP, we correlated MR images of postmortem fetal brains with variously stained histological sections of age-matched brains. On Tlw MR images (2T Prestige), the SP is clearly delineated as a zone of low signal intensity, situated between the cortical plate and external axonal stratum. This low intensity probably reflects special biochemical and cytological features of the SP, i.e., its high water content, large extracellular space, and fibrillar structure. The SP appears around 15 weeks of gestation (WG), becomes extensive at 22 WG and expands further until 30 WG, when its resolution begins in depth of cortic...

INTRODUCTION Several studies have indicated that the shape of the brain can be influenced by experience and environment. Whether these shape changes occur rapidly and consistently in a learning paradigm is, however, still unknown. METHODS In this study ...

Simultaneous neural recordings taken from multiple areas of the rodent brain are garnering growing interest because of the insight they can provide about spatially distributed neural circuitry. The promise of such recordings has inspired great progress in methods for surgically implanting large numbers of metal electrodes into intact rodent brains. However, methods for localizing the precise location of these electrodes have remained severely lacking. Traditional histological techniques that require slicing and staining of physical brain tissue are cumbersome and become increasingly impractical as the number of implanted electrodes increases. Here we solve these problems by describing a method that registers 3D computed tomography (CT) images of intact rat brains implanted with metal electrode bundles to a magnetic resonance imaging histology (MRH) atlas. Our method allows accurate visualization of each electrode bundle’s trajectory and location without removing the electrodes from the brain or surgically ...

Early childhood is a critical period showing experience-dependent changes in brain structure and function. The complex link between the structural connectivity (SC) and functional connectivity (FC) of the brain is of particular interest. However, its relationship with both age and attention in early childhood is not well understood. In this study, children between the ages of 4 and 7, and at a one-year follow-up visit, underwent neuroimaging (diffusion-weighted and passive-viewing functional magnetic resonance imaging) and assessments for selective, sustained, and executive attention. We examined regional graph metrics and SC-FC coupling of the structural and functional networks. Partial least squares (PLS) was used to investigate longitudinal brain measure changes and cross-sectional associations with age and attention. We observed longitudinal changes in functional graph metrics and age-related decreases in SC modularity. Region-wise graph analyses revealed variable brain-behaviour relationships across t...