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1. There is evidence for pronounced brain plasticity during postnatal maturation. The authors hypothesized that left-hemisphere lesion would be associated with greater than normal language participation of the right hemisphere and that atypical asymmetry of perisylvian language activations would be enhanced after lesion occurring in early childhood as(More)
The role of serotonin in prenatal and postnatal brain development is well documented in the animal literature. In earlier studies using positron emission tomography (PET) with the tracer alpha[(11)C]methyl-l-tryptophan (AMT), we reported global and focal abnormalities of serotonin synthesis in children with autism. In the present study, we measured brain(More)
Functional neuroimaging studies have shown enhanced right-hemisphere language activations in adults with left-hemisphere damage. We hypothesized that this effect would be stronger in patients with lesion occurring early in development. Using [15O]-water PET, we studied eight normal adults and 23 patients with unilateral left lesion during rest, listening to(More)
Based on reports of increased platelet serotonin in 30 to 50% of autistic subjects, abnormal serotonergic neurotransmission may be important in the pathogenesis of autism. However, serotonin metabolite measurements in cerebrospinal fluid of autistic subjects have failed to demonstrate consistent abnormalities. Using alpha-[11C]methyl-L-tryptophan as a(More)
OBJECTIVE To examine the relationship between autism and epilepsy in relation to structural and functional brain abnormalities in children with tuberous sclerosis complex (TSC). METHODS Children with TSC and intractable epilepsy underwent MRI as well as PET scans with 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) and alpha-[(11)C]methyl-L-tryptophan (AMT).(More)
Several reports have indicated that cortical resection is effective in alleviating intractable epilepsy in children with tuberous sclerosis complex (TSC). Because of the multitude of cortical lesions, however, identifying the epileptogenic tuber(s) is difficult and often requires invasive intracranial electroencephalographic (EEG) monitoring. As increased(More)
Neuropsychological studies suggest that good long-term language outcome is possible following extensive early left-hemisphere damage. We explored the brain organization for language in children with early unilateral lesion, using [15O]-water PET. In 12 patients with left lesion (LL) and 9 patients with right lesion (RL), cerebral blood flow changes during(More)
We describe the tracer kinetic analysis of [C-11]-labeled alpha-methyl-tryptophan (AMT), an analogue of tryptophan, which has been developed as a tracer for serotonin synthesis using positron emission tomography (PET) in human brain. Dynamic PET data were acquired from young healthy volunteers (n = 10) as a series of 22 scans covering a total of 60 minutes(More)
We explored the effects of maturational plasticity on motor activations for the affected hand in patients with unilateral lesion involving the rolandic cortex. Ten patients with early lesion (onset < 4 years), seven patients with late lesion (onset > or = 10 years) and eight normal adults underwent [15O]-water positron emission tomography (PET). Rolandic(More)
Recent evidence suggests disturbances of serotonin synthesis affecting the dentato-thalamo-cortical pathway in autistic boys. We studied possible effects of such disturbances on brain activations for language in autistic adults. Four autistic and five normal men were studied while listening to, repeating, and generating sentences, using [15(O)]-water(More)