Feb 24

Structural Abnormalities in the Brains of Human Subjects Who Use Methamphetamine

We visualize, for the first time, the profile of structural deficits in the human brain associated with chronic methamphetamine (MA) abuse. Studies of human subjects who have used MA chronically have revealed deficits in dopaminergic and serotonergic systems and cerebral metabolic abnormalities. Using magnetic resonance imaging (MRI) and new computational brain-mapping techniques, we determined the pattern of structural brain alterations associated with chronic MA abuse in human subjects and related these deficits to cognitive impairment. We used high-resolution MRI and surface-based computational image analyses to map regional abnormalities in the cortex, hippocampus, white matter, and ventricles in 22 human subjects who usedMAand 21 age-matched, healthy controls. Cortical maps revealed severe gray-matter deficits in the cingulate, limbic, and paralimbic cortices ofMAabusers (averaging 11.3% below control;p-0.05). On average,MAabusers had 7.8% smaller hippocampal volumes than control subjects ( p-0.01; left, p-0.01; right, p-0.05) and significant white-matter hypertrophy (7.0%; p - 0.01). Hippocampal deficits were mapped and correlated with memory performance on a word-recall test ( p- 0.05). MRI-based maps suggest that chronic methamphetamine abuse causes a selective pattern of cerebral deterioration that contributes to impaired memory performance. MA may selectively damage the medial temporal lobe and, consistent with metabolic studies, the cingulate–limbic cortex, inducing neuroadaptation, neuropil reduction, or cell death. Prominent white-matter hypertrophy may result from altered myelination and adaptive glial changes, including gliosis secondary to neuronal damage. These brain substrates may help account for the symptoms of MA abuse, providing therapeutic targets for drug-induced brain injury.
Key words: methamphetamine; brain imaging; drug abuse; MRI; cortex; hippocampus; limbic system; memory introduction Methamphetamine (MA) abuse is a growing epidemic worldwide. Read the rest of this entry »

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Feb 22

Context:Wepreviously detected a dynamic wave of gray matter loss in childhood-onset schizophrenia that started in parietal association cortices and proceeded frontally to envelop dorsolateral prefrontal and temporal cortices, including superior temporal gyri.

Objective: To map gray matter loss rates across the medial hemispheric surface, including the cingulate and medial frontal cortex, in the same cohort studied previously.
Design: Five-year longitudinal study.


Setting: National Institute of Mental Health, Bethesda, Md.

Subjects: Twelve subjects with childhood-onset schizophrenia, 12 healthy controls, and 9 medication- and IQmatched subjects with psychosis not otherwise specified.

Interventions: Three-dimensional magnetic resonance imaging at baseline and follow-up.

Main Outcome Measures: Gyral pattern and shape variations encoded by means of high-dimensional elastic deformation mappings driving each subject’s cortical anatomy onto a group average; changes in cortical gray matter mapped by computing warping fields that matched sulcal patterns across hemispheres, subjects, and time.

Results: Selective, severe frontal gray matter loss occurred bilaterally in a dorsal-to-ventral pattern across the medial hemispheric surfaces in the schizophrenic subjects.
A sharp boundary in the pattern of gray matter loss separated frontal regions and cingulate-limbic areas.

Conclusion: Frontal and limbic regions may not be equally vulnerable to gray matter attrition, which is consistent with the cognitive, metabolic, and functional vulnerability of the frontal cortices in schizophrenia. Read the rest of this entry »

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