Magnetic Resonance Imaging (MRI)

We present original results and review literature from the past fifty years that address the role of primate auditory cortex in the following perceptual capacities: (1) the ability to perceive small differences between the pitches of two successive tones; (2) the ability to perceive the sign (i.e., direction) of the pitch difference [higher (+) vs. lower (-)]; and (3) the ability to abstract pitch constancy across changes in stimulus acoustics.

We present an MRI-based anatomic analysis of a series of seven human brains with the semilobar form of holoprosencephaly. The analysis defines a set of common descriptors for a pattern of topological anomaly which is uniform for the set of seven brains. The core of the anomaly is a rostro-caudally aligned midline gray matter 'seam' that extends from the telencephalic-suprachiasmatic junctional region to abut the posterior aspect of the callosal commissure. The seam forms the ventricular roof throughout its extent. Rostrally it is formed by the conjoined heads of caudate/accumbens nuclei.

We present an MRI-based anatomic analysis of a series of 9 human brains, representing lobar, semilobar and alobar forms of holoprosencephaly. The analysis of these variable forms of the malformation is based upon a topologic systematics established in a prior analysis of a homogeneous set of semilobar malformations. This systematics has the dual advantage that it serves both as a uniform reference for qualitative description and as a quantitative descriptive base for mathematical correlations between parameters of topology and of growth and development.

Abstract We describe a system of parcellation of the human neocortex, based upon magnetic resonance images, that conserves the topographic uniqueness of the individual brain. Subdivision of the neocortex, according to this system, is based entirely upon the configuration of a specified set of cerebral landmarks, principally neocortical fissures. These are present but unique in the details of their configurations in each individual brain.

OBJECTIVE: To evaluate the impact of therapeutic oral doses of stimulants on the brains of ADHD subjects as measured by magnetic resonance imaging (MRI)-based neuroimaging studies (morphometric, functional, spectroscopy).
DATA SOURCES: We searched PubMed and ScienceDirect through the end of calendar year 2011 using the keywords (1) psychostimulants or methylphenidate or amphetamine, and (2) neuroimaging or MRI or fMRI, and (3) ADHD or ADD or attention-deficit/hyperactivity disorder or attention deficit hyperactivity disorder.

We performed cerebellum segmentation and parcellation on magnetic resonance images from right-handed boys, aged 6-13 years, including 22 boys with autism [16 with language impairment (ALI)], 9 boys with Specific Language Impairment (SLI), and 11 normal controls. Language-impaired groups had reversed asymmetry relative to unimpaired groups in posterior-lateral cerebellar lobule VIIIA (right side larger in unimpaired groups, left side larger in ALI and SLI), contralateral to previous findings in inferior frontal cortex language areas. Lobule VIIA Crus I was smaller in SLI than in ALI.

BACKGROUND: Basal ganglia (BG) enlargement has been found in studies of adults with bipolar disorder (BPD), while the few studies of BPD youths have had mixed findings. The BG (caudate, putamen, globus pallidus, nucleus accumbens) is interconnected with limbic and prefrontal cortical structures and therefore may be implicated in BPD.

This article applies a unified approach to variational smoothing and segmentation to brain diffusion tensor image data along user-selected attributes derived from the tensor, with the aim of extracting detailed brain structure information. The application of this framework simultaneously segments and denoises to produce edges and smoothed regions within the white matter of the brain that are relatively homogeneous with respect to the diffusion tensor attributes of choice.

Our objective was to test for differences between subjects with obsessive-compulsive disorder (OCD) and healthy controls with respect to white matter architecture within the cingulum bundle (CB) and anterior limb of the internal capsule (ALIC). We studied eight subjects with active OCD and 10 matched healthy controls using diffusion tensor magnetic resonance imaging (DT-MRI) at 1.5 T (Tesla). Fractional anisotropy (FA) was evaluated in both CB and ALIC. Both voxelwise and region-of-interest methods of analysis were employed.

Previous research in non-human primates has shown that the superior longitudinal fascicle (SLF), a major intrahemispheric fiber tract, is actually composed of four separate components. In humans, only post-mortem investigations have been available to examine the trajectory of this tract. This study evaluates the hypothesis that the four subcomponents observed in non-human primates can also be found in the human brain using in vivo diffusion tensor magnetic resonance imaging (DT-MRI).