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1,209 results on '"Fowler, Joanna S."'

10. Association between Dopamine D4 Receptor Polymorphism and Age Related Changes in Brain Glucose Metabolism

Author

Volkow, Nora D., Tomasi, Dardo, Wang, Gene-Jack, Telang, Frank, Fowler, Joanna S., Goldstein, Rita Z., Klein, Nelly, Wong, Christopher, Swanson, James M., and Shumay, Elena

Abstract

Aging is associated with reductions in brain glucose metabolism in some cortical and subcortical regions, but the rate of decrease varies significantly between individuals, likely reflecting genetic and environmental factors and their interactions. Here we test the hypothesis that the variant of the dopamine receptor D4 (DRD4) gene (VNTR in exon 3), which has been associated with novelty seeking and sensitivity to environmental stimuli (negative and positive) including the beneficial effects of physical activity on longevity, influence the effects of aging on the human brain. We used positron emission tomography (PET) and [18F]fluoro-D-glucose (18FDG) to measure brain glucose metabolism (marker of brain function) under baseline conditions (no stimulation) in 82 healthy individuals (age range 22–55 years). We determined their DRD4 genotype and found an interaction with age: individuals who did not carry the 7-repeat allele (7R−, n = 53) had a significant (p

Published
2013

11. Long-Term Stimulant Treatment Affects Brain Dopamine Transporter Level in Patients with Attention Deficit Hyperactive Disorder

Author

Wang, Gene-Jack, Volkow, Nora D., Wigal, Timothy, Kollins, Scott H., Newcorn, Jeffrey H., Telang, Frank, Logan, Jean, Jayne, Millard, Wong, Christopher T., Han, Hao, Fowler, Joanna S., Zhu, Wei, and Swanson, James M.

Abstract

ObjectiveBrain dopamine dysfunction in attention deficit/hyperactivity disorder (ADHD) could explain why stimulant medications, which increase dopamine signaling, are therapeutically beneficial. However while the acute increases in dopamine induced by stimulant medications have been associated with symptom improvement in ADHD the chronic effects have not been investigated.MethodWe used positron emission tomography and [11C]cocaine (dopamine transporter radioligand) to measure dopamine transporter availability in the brains of 18 never-medicated adult ADHD subjects prior to and after 12 months of treatment with methylphenidate and in 11 controls who were also scanned twice at 12 months interval but without stimulant medication. Dopamine transporter availability was quantified as non-displaceable binding potential using a kinetic model for reversible ligands.ResultsTwelve months of methylphenidate treatment increased striatal dopamine transporter availability in ADHD (caudate, putamen and ventral striatum: +24%, p

Published
2013

12. Low Monoamine Oxidase B in Peripheral Organs in Smokers

Author

Fowler, Joanna S., Logan, Jean, Wang, Gene-Jack, Volkow, Nora D., Telang, Frank, Zhu, Wei, Franceschi, Dinko, Pappas, Naomi, Ferrieri, Richard, Shea, Colleen, Garza, Victor, Xu, Youwen, Schlyer, David, Gatley, S. John, Ding, Yu-Shin, Alexoff, David, Warner, Donald, Netusil, Noelwah, Carter, Pauline, Jayne, Millard, King, Payton, and Vaska, Paul

Published
2003

14. Methylphenidate Decreased the Amount of Glucose Needed by the Brain to Perform a Cognitive Task

Author

Volkow, Nora D., Fowler, Joanna S., Wang, Gene-Jack, Telang, Frank, Logan, Jean, Wong, Christopher, Ma, Jim, Pradhan, Kith, Benveniste, Helene, and Swanson, James M.

Abstract

The use of stimulants (methylphenidate and amphetamine) as cognitive enhancers by the general public is increasing and is controversial. It is still unclear how they work or why they improve performance in some individuals but impair it in others. To test the hypothesis that stimulants enhance signal to noise ratio of neuronal activity and thereby reduce cerebral activity by increasing efficiency, we measured the effects of methylphenidate on brain glucose utilization in healthy adults. We measured brain glucose metabolism (using Positron Emission Tomography and 2-deoxy-2[18F]fluoro-D-glucose) in 23 healthy adults who were tested at baseline and while performing an accuracy-controlled cognitive task (numerical calculations) given with and without methylphenidate (20 mg, oral). Sixteen subjects underwent a fourth scan with methylphenidate but without cognitive stimulation. Compared to placebo methylphenidate significantly reduced the amount of glucose utilized by the brain when performing the cognitive task but methylphenidate did not affect brain metabolism when given without cognitive stimulation. Whole brain metabolism when the cognitive task was given with placebo increased 21% whereas with methylphenidate it increased 11% (50% less). This reflected both a decrease in magnitude of activation and in the regions activated by the task. Methylphenidate's reduction of the metabolic increases in regions from the default network (implicated in mind-wandering) was associated with improvement in performance only in subjects who activated these regions when the cognitive task was given with placebo. These results corroborate prior findings that stimulant medications reduced the magnitude of regional activation to a task and in addition document a “focusing” of the activation. This effect may be beneficial when neuronal resources are diverted (i.e., mind-wandering) or impaired (i.e., attention deficit hyperactivity disorder), but it could be detrimental when brain activity is already optimally focused. This would explain why methylphenidate has beneficial effects in some individuals and contexts and detrimental effects in others.

Published
2008

28. Imaging Studies in Substance Abuse

Author

Volkow, Nora D., Fowler, Joanna S., Wang, Gene-Jack, Shreeve, Walton W., Feinendegen, Ludwig E., editor, Shreeve, Walton W., editor, Eckelman, William C., editor, Bahk, Yong-Whee, editor, and Wagner, Henry N., Jr., editor

Published
2003
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34. Pharmacology of Cocaine

Author

Gatley, S. John, Gifford, Andrew N., Volkow, Nora D., Fowler, Joanna S., Tarter, Ralph E., editor, Ammerman, Robert T., editor, and Ott, Peggy J., editor

Published
1998
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40. Naloxone’s displacement of [11C]carfentanil and duration of receptor occupancy in the rat brain: implications for opioid overdose reversal

Author

Kang, Yeona, primary, O’Conor, Kelly A., additional, Kelleher, Andrew, additional, Ramsey, Joseph, additional, Bakhoda, Gus, additional, Eisenberg, Seth M., additional, Zhao, Wenjing, additional, Stodden, Tyler, additional, Pearson, Torben, additional, Guo, Min, additional, Brown, Nina, additional, Liow, Jeih-San, additional, Fowler, Joanna S, additional, Kim, Sung Won, additional, and Volkow, Nora D, additional

Published
2022
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46. Discovery of Highly Potent Adenosine A1 Receptor Agonists: Targeting Positron Emission Tomography Probes

Author

Guo, Min, primary, Bakhoda, Abolghasem, additional, Gao, Zhan-Guo, additional, Ramsey, Joseph M., additional, Li, Yang, additional, O’Conor, Kelly A., additional, Kelleher, Andrew C., additional, Eisenberg, Seth M., additional, Kang, Yeona, additional, Yan, Xuefeng, additional, Javdan, Cameron, additional, Fowler, Joanna S., additional, Rice, Kenner C., additional, Hooker, Jacob M., additional, Jacobson, Kenneth A., additional, Kim, Sung Won, additional, and Volkow, Nora D., additional

Published
2021
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