Why Rome trembles: "E avanti a lui tremava tutta Roma!" (Tosca, Act II).
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Aspartic Acid↗
Biomedical subjects
David A Rottenberg
Publications and source records attributed to David A Rottenberg.
Cluster analysis of activity-time series in motor learning.
Neuroimaging studies of learning focus on brain areas where the activity changes as a function of time. To circumvent the difficult problem of model selection, we used a data-driven analytic tool, cluster analysis, which extracts representative temporal and spatial patterns from the voxel-time series. The optimal number of clusters was chosen using a cross-validated likelihood method, which highlights the clustering pattern that generalizes best over the subjects. Data were acquired with PET at different time points during practice of a visuomotor task. The results from cluster analysis show practice-related activity in a fronto-parieto-cerebellar network, in agreement with previous studies of motor learning. These voxels were separated from a group of voxels showing an unspecific time-effect and another group of voxels, whose activation was an artifact from smoothing.
Adult↗
Production and dosimetry of [14O]water for PET activation studies.
[14O]water was produced by the 14N(p,n)14O reaction in quantities greater than 80mCi (EOB). The carbon-11 impurity in the final product was approximately 0.003 +/- 0.002% of 14O activity at EOB. A factor of 0.5 +/- 0.02 was obtained to correct the dose calibrator for the additional 2.313 MeV gamma-ray. The effective dose equivalent was calculated for 14O and 15O using MIRDOSE, and the 14O dose was found to be approximately 70% of that for 15O. For scanner performance based on noise equivalent count measurements, the peak activity concentration for 14O was 30% lower than that for 15O. At their peak activity concentrations the noise equivalent count rate for 14O was found to be about 13% less than that for 15O.
Blood Circulation↗
Compulsive thalamic self-stimulation: a case with metabolic, electrophysiologic and behavioral correlates.
A 48-year-old woman with a stimulating electrode implanted in the right thalamic nucleus ventralis posterolateralis developed compulsive self-stimulation associated with erotic sensations and changes in autonomic and neurologic function. Stimulation effects were evaluated by neuropsychologic testing, endocrine studies, positron emission tomographic measurements of regional cerebral metabolic rate for glucose, EEG and evoked potentials. During stimulation, vital signs and pupillary diameter increased and a left hemiparesis and left hemisensory loss developed. Verbal functions deteriorated and visuospatial processing improved. Plasma growth hormone concentrations decreased, and adrenocorticotrophic hormone and cortisol levels rose. With stimulation, glucose metabolism increased in both thalami and both hemispheres, reversing baseline right-sided hypometabolism and right-left asymmetries. EEG and both somatosensory and brain-stem auditory evoked potentials remained unchanged during stimulation, while visual evoked potentials revealed evidence of anterior visual pathway dysfunction in the left eye. This case establishes the potential for addiction to deep brain stimulation and demonstrates that widespread behavioral and physiological changes, with concomitant alteration in the regional cerebral metabolic rate for glucose, may accompany unilateral thalamic stimulation.
Brain↗