Biological psychiatry
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Biological psychiatry · Apr 2005
Comparative Study Clinical TrialCortical and subcortical brain effects of transcranial magnetic stimulation (TMS)-induced movement: an interleaved TMS/functional magnetic resonance imaging study.
To date, interleaved transcranial magnetic stimulation and functional magnetic resonance imaging (TMS/fMRI) studies of motor activation have not recorded whole brain patterns. We hypothesized that TMS would activate known motor circuitry with some additional regions plus some areas dropping out. ⋯ Using this interleaved TMS/fMRI technique, TMS over primary motor cortex produces a whole brain pattern of BOLD activation similar to known motor circuitry, without detectable differences from mimicked volitional movement. Some differences may exist between time courses of BOLD intensity during TMS circuit activation and volitional circuit activation.
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Biological psychiatry · Mar 2005
Comparative StudyMitochondrial DNA 3243A>G mutation and increased expression of LARS2 gene in the brains of patients with bipolar disorder and schizophrenia.
Accumulating evidence suggests mitochondrial dysfunction in bipolar disorder. Analyses of mitochondria-related genes using DNA microarray showed significantly increased LARS2 (mitochondrial leucyl-tRNA synthetase) in the postmortem prefrontal cortices of patients with bipolar disorder provided by the Stanley Foundation Brain Collection. LARS2 is a nuclear gene encoding the enzyme catalyzing the aminoacylation of mitochondrial tRNA(Leu). A well-studied mitochondrial DNA point mutation, 3243A>G, in the region of tRNA(Leu (UUR)), related with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), is known to decrease the efficiency of aminoacylation of tRNA(Leu (UUR)). ⋯ These results suggest that upregulation of LARS2 is a hallmark of 324A>G mutation. The accumulation of 3243A>G mutation in the brain may have a pathophysiologic role in bipolar disorder and schizophrenia.
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Biological psychiatry · Jan 2005
Randomized Controlled Trial Clinical TrialTranscranial magnetic stimulation accelerates the antidepressant effect of amitriptyline in severe depression: a double-blind placebo-controlled study.
Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex, and the treatment of depression is one of its potential therapeutic applications. Three recent meta analyses strongly suggest its benefits in the treatment of depression. The present study investigates whether repetitive TMS (rTMS) accelerates the onset of action and increases the therapeutic effects of amitriptyline. ⋯ Repetitive TMS at 5 Hz accelerated the onset of action and augmented the response to amitriptyline.
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Biological psychiatry · Nov 2004
Comparative StudyCerebrospinal fluid beta-amyloid1-42 and tau in control subjects at risk for Alzheimer's disease: the effect of APOE epsilon4 allele.
Cerebrospinal fluid (CSF) measures of beta-amyloid(1-42) and tau are linked with the known neuropathology of Alzheimer's disease (AD). Numerous lines of evidence have also suggested that individuals with at least one APOE epsilon4 allele on chromosome 19 are at increased risk of developing AD. We tested these CSF markers in groups of subjects with AD and healthy older control subjects, using the absence or presence of the APOE epsilon4 allele as a predictive variable in the search for possible prognostic biomarkers of AD. ⋯ The association of APOE epsilon4 allele and lower, more AD-like levels of CSF beta-amyloid(1-42) in older control subjects is consistent with previous studies showing possible neuroimaging and cognitive abnormalities with epsilon4 carriers and suggests that CSF beta-amyloid(1-42) decreases might represent an early biomarker of AD. Longitudinal follow-up is of course required to verify whether this biomarker is indeed predictive of clinical conversion to AD.
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Biological psychiatry · Nov 2004
ReviewNew approaches for exploring anatomical and functional connectivity in the human brain.
Information processing in the primate brain is based on the complementary principles of modular and distributed information processing. The former emphasizes the specialization of functions within different brain areas. ⋯ Here, we highlight recent advances in neuroimaging methodology that have made it possible to investigate the anatomical architecture of networks in the living human brain with diffusion tensor imaging (DTI). We also highlight recent thinking on the ways in which functional imaging can be used to characterize information transmission across networks in the human brain (functional and effective connectivity).