N-acetylaspartate reductions in the mediodorsal and anterior thalamus in men with schizophrenia verified by tissue volume corrected proton MRSI.

Objective: Deficits in the mediodorsal and anterior nuclei of the thalamus may contribute to the psychopathological symptoms of schizophrenia. These thalamic nuclei have been found to be abnormal in schizophrenia and have close connections with other brain structures implicated in the disorder. We therefore examined schizophrenia-related alterations in brain metabolite levels specifically in the mediodorsal and anterior thalamic subregions.

Lower concentration of hippocampal N-acetylaspartate in familial bipolar I disorder.

Objective: Previous studies attempting to identify neuropathological alterations in the hippocampus in bipolar disorder have been inconclusive. The objective of this study was to determine if the concentration of N-acetylaspartate, a neuronal and axonal marker, was lower in subjects with familial bipolar I disorder than in healthy comparison subjects, suggesting possible neuronal loss, neuronal dysfunction, or neuropil reduction in bipolar I disorder.

Method: N-acetylaspartate, choline, and creatine in the right and left hippocampus were measured in 15 euthymic male patients with familial bipolar I disorder and 20 healthy male comparison subjects by using proton magnetic resonance spectroscopy ((1)H-MRS).

Magnetic resonance imaging of the thalamus in male patients with schizophrenia.

Thalamic abnormalities have been hypothesized to explain much of the psychopathology in schizophrenia, however, quantitative magnetic resonance imaging (MRI) studies have yielded discrepant results as to whether there are thalamic volume alterations. The current study utilized high resolution MRI and an axial voluming protocol to determine if there was a significant reduction in the volume of the thalamus in patients with schizophrenia. Quantitative analysis was performed on magnetic resonance images of the brain in 41 male medicated schizophrenic patients and 39 male normal control subjects similar in age, education and handedness.

Evidence for anterior cingulate cortex involvement in monitoring preparatory attentional set.

An important cognitive function underlying unified, voluntary behavior is attentional control. Two frontal regions, anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC), appear to be particularly involved in attentional control and monitoring. In this study, we investigated whether ACC is involved in monitoring the preparatory allocation of attention during task switching, or whether ACC is active only when subjects are processing target stimuli and selecting a response, via a cued-attention design.

Quantitative 1H magnetic resonance spectroscopy and MRI of Parkinson's disease.

Magnetic resonance imaging (MRI) and (1)H magnetic resonance spectroscopy (MRS) of the substantia nigra, basal ganglia, and cerebral cortex were performed on 10 patients with Parkinson's disease (PD) and 13 age-matched, healthy control subjects. Compared to controls, PD patients had approximately 24% lower creatine in the region of the substantia nigra and smaller volumes of the putamen (11%), globus pallidus (16%), and prefrontal cortex (6%; all P < 0.05).

Patterns of brain atrophy in frontotemporal dementia and semantic dementia.

Objective: To identify and compare the patterns of cerebral atrophy associated with two clinical variants of frontotemporal lobar degeneration (FTLD): frontotemporal dementia (FTD) and semantic dementia (SemD).

Methods: Twenty patients with FTLD were classified as having FTD (N = 8) or SemD (N = 12) based on current clinical criteria. Both groups showed a similar spectrum of behavioral abnormalities, as indicated by the neuropsychiatric inventory.

Evidence for altered cerebellar vermis neuronal integrity in schizophrenia.

To determine if there was evidence for altered neuronal integrity in the cerebellar vermis of patients with schizophrenia, the authors measured N-acetyl-aspartate (NAA, a putative neuronal/axonal marker) using in vivo proton magnetic resonance spectroscopic imaging (1H-MRSI) in 20 chronically medicated male patients with schizophrenia and 15 male comparison subjects. Relative contributions of cerebrospinal fluid, gray matter, and white matter to each MRSI voxel were determined using an MRI tissue segmentation technique. The percentage of tissue was used as a co-variate to determine the extent to which tissue composition contributed to NAA differences.

Detection of clinically silent infarcts after carotid endarterectomy by use of diffusion-weighted imaging.

Background And Purpose: Intraprocedural transcranial Doppler sonography has identified multiple microembolic events during and immediately after carotid endarterectomy (CEA) or angioplasty, yet the rate of clinically evident stroke is small. To determine the significance of the transcranial Doppler sonography findings, we examined patients by use of diffusion-weighted imaging and fluid-attenuated inversion recovery MR imaging before and immediately after CEA for evidence of clinically silent ischemic events.

Methods: Twenty-five patients with atherosclerotic disease of the carotid arteries underwent diffusion-weighted imaging and fluid-attenuated inversion recovery MR imaging performed, on average, 3 days before and 12 hours after CEA.

Increased thalamic N-acetylaspartate in male patients with familial bipolar I disorder.

N-Acetylaspartate (NAA) in the anterior and mediodorsal thalamic regions was measured using proton magnetic resonance spectroscopic imaging (1H-MRSI) in 15 euthymic male patients with familial bipolar I disorder and compared to values in 15 male control subjects to determine if there was evidence for altered neuronal/axonal integrity. MRI tissue segmentation methods were also utilized to obtain tissue-contribution estimates for each MRSI voxel. Relative to the comparison group, the patients with bipolar I disorder demonstrated significantly higher NAA and creatine in both the right and left thalamus.

Diminished regional cerebral blood flow response to vibration in patients with blepharospasm.

Objective: To determine whether patients with blepharospasm have abnormal sensorimotor processing similar to patients with writer's cramp.

Background: Blepharospasm is a focal dystonia manifest by involuntary, excessive blinking and squeezing of the eyes. Altered sensorimotor processing may contribute to the development of dystonic movements.

Functional magnetic resonance imaging of the basal ganglia and cerebellum using a simple motor paradigm.

Activation of cortical and subcortical motor areas of the brain, including primary motor cortex, supplementary motor area, basal ganglia and cerebellum, were successfully investigated in seven right-handed, normal volunteers during a simple, rapid, thumb flexion-extension task using functional magnetic resonance imaging. A multi-slice echo-planar imaging sequence was used to cover the entire brain. A signal increase varying from 2% to 6% was observed for the different regions involved in the motor task.

Regulation of bacteriophage P2 late-gene expression: the ogr gene.

The ogr gene product of bacteriophage P2 is a positive regulatory factor required for P2 late-gene transcription. We have determined the nucleotide sequence of the ogr gene, which encodes a basic polypeptide of 72 amino acids. P2 growth is blocked by a host mutation, rpoA109, in the alpha subunit of DNA-dependent RNA polymerase.