Richard E. Carson

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To assess dynamic changes in brain function throughout the sleep-wake cycle, CBF was measured with H2(15)O and PET in 37 normal male volunteers: (i) while awake prior to sleep onset; (ii) during Stage 3-4 sleep, i.e. slow wave sleep (SWS); (iii) during rapid eye movement (REM) sleep; and (iv) upon waking following recovery sleep. Subjects were monitored(More)
A major line of evidence that supports the hypothesis of dopamine overactivity in schizophrenia is the psychomimetic potential of agents such as amphetamine that stimulate dopamine outflow. A novel brain imaging method provides an indirect measure of in vivo synaptic dopamine concentration by quantifying the change in dopamine receptor radiotracer binding(More)
To assess dynamic brain function in adults who had stuttered since childhood, regional cerebral blood flow (rCBF) was measured with H2O and PET during a series of speech and language tasks designed to evoke or attenuate stuttering. Speech samples were acquired simultaneously and quantitatively compared with the PET images. Both hierarchical task contrasts(More)
SUMMARY The authors developed and applied two new linearized reference tissue models for parametric images of binding potential (BP) and relative delivery (R1) for [11C]DASB positron emission tomography imaging of serotonin transporters in human brain. The original multilinear reference tissue model (MRTM(O)) was modified (MRTM) and used to estimate a(More)
The existence and neuroanatomical locations of separate extrastriate visual pathways for object recognition and spatial localization were investigated in healthy young men. Regional cerebral blood flow was measured by positron emission tomography and bolus injections of H2(15)O, while subjects performed face matching, dot-location matching, or sensorimotor(More)
To determine the neural circuitry engaged by performance of the Wisconsin Card Sorting Test (WCST), a neuropsychological test traditionally considered to be sensitive to prefrontal lesions, regional cerebral blood flow was measured with oxygen-15 water and positron emission tomography (PET) while young normal subjects performed the test as well as while(More)
The Simplified Reference Tissue Model (SRTM) produces functional images of receptor binding parameters using an input function derived from a reference region and assuming a model with one tissue compartment. Three parameters are estimated: binding potential (BP), relative delivery (R1), and the reference region clearance constant k'2. Since k'2 should not(More)
Positron emission tomography was used to measure cerebral activity and to evaluate regional interrelationships within visual cortices and their projections during rapid eye movement (REM) sleep in human subjects. REM sleep was associated with selective activation of extrastriate visual cortices, particularly within the ventral processing stream, and an(More)
In an attempt to improve neuroreceptor distribution volume (V) estimates, the authors evaluated three alternative linear methods to Logan graphical analysis (GA): GA using total least squares (TLS), and two multilinear analyses, MA1 and MA2, based on mathematical rearrangement of GA equation and two-tissue compartments, respectively, using simulated and(More)