Author
Robert M. Kessler
Other affiliations: Vanderbilt University, Vanderbilt University Medical Center
Bio: Robert M. Kessler is an academic researcher from University of Alabama at Birmingham. The author has contributed to research in topics: Dopamine receptor D2 & Fallypride. The author has an hindex of 41, co-authored 108 publications receiving 7964 citations. Previous affiliations of Robert M. Kessler include Vanderbilt University & Vanderbilt University Medical Center.
Papers published on a yearly basis
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TL;DR: The results indicate that retrospective techniques have the potential to produce satisfactory results much of the time, but that visual inspection is necessary to guard against large errors.
Abstract: Comparison and evaluation of retrospective intermodality brain image registration techniques
835 citations
TL;DR: Functional magnetic resonance imaging data suggest heightened pain sensitivity of the brain-gut axis in IBS, with a normal pattern of activation.
573 citations
TL;DR: It is found that higher levels of trait impulsivity were predicted by diminished midbrain D2/D3 autoreceptor binding and greater amphetamine-induced DA release in the striatum, which was in turn associated with stimulant craving.
Abstract: Dopamine (DA) has long been implicated in impulsivity, but the precise mechanisms linking human variability in DA signaling to differences in impulsive traits remain largely unknown. By using a dual-scan positron emission tomography approach in healthy human volunteers with amphetamine and the D2/D3 ligand [18F]fallypride, we found that higher levels of trait impulsivity were predicted by diminished midbrain D2/D3 autoreceptor binding and greater amphetamine-induced DA release in the striatum, which was in turn associated with stimulant craving. Path analysis confirmed that the impact of decreased midbrain D2/D3 autoreceptor availability on trait impulsivity is mediated in part through its effect on stimulated striatal DA release.
557 citations
TL;DR: Local cerebral uptake of deoxyglucose labeled with fluorine 18 was measured by positron-emission tomography in eight patients with schizophrenia and in six age-matched normal volunteers, indicating relatively lower glucose use than normal control subjects.
Abstract: • Local cerebral uptake of deoxyglucose labeled with fluorine 18 was measured by positron-emission tomography in eight patients with schizophrenia who were not receiving medication and in six age-matched normal volunteers. Subjects sat in an acoustically treated, darkened room with eyes closed after injection of 3 to 5 mCi of deoxyglucose18F. After uptake, seven to eight horizontal brain scans parallel to the canthomeatal line were done. Scans were treated digitally, with a 2.3-cm strip peeled off each slice and ratios to whole-slice activity computed. Patients with schizophrenia showed lower ratios in the frontal cortex, indicating relatively lower glucose use than normal control subjects; this was consistent with previously reported studies of regional cerebral blood flow. Patients also showed diminished ratios for a 2.3-cm square that was positioned over central gray-matter areas on the left but not on the right side. These findings are preliminary; issues of control of mental activity, brain structure identification, and biologic and anatomic heterogeneity of schizophrenia remain to be explored.
509 citations
TL;DR: These findings suggest that neurochemical and neurophysiological hyper-reactivity of the dopaminergic reward system may comprise a neural substrate for impulsive-antisocial behavior and substance abuse in psychopathy.
Abstract: Psychopathy is a disorder that has typically been considered to result from a primary deficit in fear or empathy. Here the authors find that impulsive-antisocial psychopathic traits are correlated with hyper-reactivity of the dopaminergic reward system as measured with positron emission tomography and functional magnetic resonance imaging.
425 citations
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TL;DR: A review of recent as well as classic image registration methods to provide a comprehensive reference source for the researchers involved in image registration, regardless of particular application areas.
6,842 citations
TL;DR: It is demonstrated that the use of local optimisation methods together with the standard multi-resolution approach is not sufficient to reliably find the global minimum, so a global optimisation method is proposed that is specifically tailored to this form of registration.
6,413 citations
TL;DR: The results clearly indicate that the proposed nonrigid registration algorithm is much better able to recover the motion and deformation of the breast than rigid or affine registration algorithms.
Abstract: In this paper the authors present a new approach for the nonrigid registration of contrast-enhanced breast MRI. A hierarchical transformation model of the motion of the breast has been developed. The global motion of the breast is modeled by an affine transformation while the local breast motion is described by a free-form deformation (FFD) based on B-splines. Normalized mutual information is used as a voxel-based similarity measure which is insensitive to intensity changes as a result of the contrast enhancement. Registration is achieved by minimizing a cost function, which represents a combination of the cost associated with the smoothness of the transformation and the cost associated with the image similarity. The algorithm has been applied to the fully automated registration of three-dimensional (3-D) breast MRI in volunteers and patients. In particular, the authors have compared the results of the proposed nonrigid registration algorithm to those obtained using rigid and affine registration techniques. The results clearly indicate that the nonrigid registration algorithm is much better able to recover the motion and deformation of the breast than rigid or affine registration algorithms.
5,490 citations