Ronald L. Cowan, Ph.D., M.D.


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Faculty Appointments
Professor of Psychiatry and Behavioral Sciences Professor of Radiology and Radiological Sciences
M.D., Cornell University Medical College, New York, New YorkPh.D., Anatomy and Neurobiology, University of Tennessee Center for Health Science, Memphis, TennesseeB.S., Christian Brothers University, Memphis, Tennessee
Office Address
3057K Psych H
Nashville, TN 37212-8645
Research Description
Our lab uses neuroimaging and complementary methods to explore the neurobiology of addiction and its consequences in humans. Studies include those of drug use and reward function, the role of mood and monoamines in drug use and reward dysfunction, drug-induced toxicity, and neural mechanisms of overeating and obesity.Specific research topics include:

1. MDMA (Ecstasy) Toxicity
These projects attempt to characterize the long-term consequences of recreational MDMA use in humans. We used multimodal MRI and MRS approaches to examine MDMA effects on brain structure, function, and chemical composition. We use PET to characterize persistent MDMA effects on brain serotonergic receptors. We also examine the relationship between brain activation and behavioral performance, personality, psychiatric symptoms, and genetic effects.

2. Neurobiology of Obesity
These projects explore the neurobiology of obesity from an addiction perspective examining food salience in obesity. fMRI studies examine the neural bases of brain responding to food cues of varying palatability and caloric density. Effects of satiety and hunger are assayed. Eye-tracking studies examine for altered attentional or incentive salience for food cues in obesity. Because altered food salience may be a major mechanism for relapse in obesity when attempting to regulate food intake, exploring the effects of caloric content, palatability, hunger and satiety on attentional salience is an essential step toward documenting the role of these mechanisms in obesity.

3. Serotonin genetics
Our studies of serotonin genetics and brain function examine the relationship between common functional allelic variations in genes encoding serotonin receptors and the serotonin reuptake transporter and brain structure, function, receptor expression, and personality.

4. Neurobiology of Euphoria
Our studies of the neurobiology of euphoria employ functional MRI during drug administration with continous mood assessment to probe the neural correlates of drug effects and to identify neural substrates mediating self-report of the euphoric mood change.
Clinical Description
Ronald Cowan, MD, PhD has been a member of the faculty since 2002. Dr. Cowan is a graduate of the Weill Cornell Medical School. He completed his internship in internal medicine at the Massachusetts General Hospital/Harvard Medical School and a residency in adult psychiatry at The McLean Hospital/Harvard Medical School. He completed his PhD at the University of Tennessee Health Science Center with a focus on in vivo intracellular neurophysiology of neocortex. Dr. Cowan is the Director of the Adult Residency Training program in the Department of Psychiatry and Behavioral Sciences. He is a Professor of Psychiatry and Behavioral Sciences, Radiology and Radiological Sciences, and Psychology. Prior to his current roles, Dr. Cowan served as a course co-director for the first year medical school's neuroscience course (Brain and Behavior), as the third year psychiatry clerkship director and as Vice Chair for Education in the Department of Psychiatry and Behavioral Sciences. Dr. Cowan's clinical interests include psychosomatic medicine, depression, substance use, obesity and LGBTQI mental health.
Research Keywords
Our lab uses neuroimaging, genetic, and behavioral methods to explore the neurobiology of reward behavior and addiction in humans. Studies include those of drug use and reward function, the role of mood and monoamines in drug use and reward dysfunction, drug-induced toxicity, and neural mechanisms of overeating and obesity.
Clinical Research Keywords
Neuroimaging, Depression, Drug Abuse, Obesity, Serotonin, Ecstasy, Prader-Willi Syndrome
Raj V, Liang HC, Woodward ND, Bauernfeind AL, Lee J, Dietrich MS, Park S, Cowan RL. MDMA (ecstasy) use is associated with reduced BOLD signal change during semantic recognition in abstinent human polydrug users: a preliminary fMRI study. J. Psychopharmacol. (Oxford) [print-electronic]. 2010 Feb; 24(2): 187-201. PMID: 19304866, PMCID: PMC3198867, PII: 0269881109103203, DOI: 10.1177/0269881109103203, ISSN: 1461-7285.

Castellanos EH, Charboneau E, Dietrich MS, Park S, Bradley BP, Mogg K, Cowan RL. Obese adults have visual attention bias for food cue images: evidence for altered reward system function. Int J Obes (Lond) [print-electronic]. 2009 Sep; 33(9): 1063-73. PMID: 19621020, PII: ijo2009138, DOI: 10.1038/ijo.2009.138, ISSN: 1476-5497.

Karageorgiou J, Dietrich MS, Charboneau EJ, Woodward ND, Blackford JU, Salomon RM, Cowan RL. Prior MDMA (Ecstasy) use is associated with increased basal ganglia-thalamocortical circuit activation during motor task performance in humans: an fMRI study. Neuroimage [print-electronic]. 2009 Jul 7/1/2009; 46(3): 817-26. PMID: 19264142, PMCID: PMC2805435, PII: S1053-8119(09)00184-0, DOI: 10.1016/j.neuroimage.2009.02.029, ISSN: 1095-9572.

Woodward ND, Zald DH, Ding Z, Riccardi P, Ansari MS, Baldwin RM, Cowan RL, Li R, Kessler RM. Cerebral morphology and dopamine D2/D3 receptor distribution in humans: a combined [18F]fallypride and voxel-based morphometry study. Neuroimage [print-electronic]. 2009 May 5/15/2009; 46(1): 31-8. PMID: 19457373, PMCID: PMC2804466, PII: S1053-8119(09)00088-3, DOI: 10.1016/j.neuroimage.2009.01.049, ISSN: 1095-9572.

Cowan RL, Joers JM, Dietrich MS. N-acetylaspartate (NAA) correlates inversely with cannabis use in a frontal language processing region of neocortex in MDMA (Ecstasy) polydrug users: a 3 T magnetic resonance spectroscopy study. Pharmacol. Biochem. Behav [print-electronic]. 2009 Mar; 92(1): 105-10. PMID: 19032963, PMCID: PMC4451227, PII: S0091-3057(08)00360-2, DOI: 10.1016/j.pbb.2008.10.022, ISSN: 0091-3057.

Zald DH, Cowan RL, Riccardi P, Baldwin RM, Ansari MS, Li R, Shelby ES, Smith CE, McHugo M, Kessler RM. Midbrain dopamine receptor availability is inversely associated with novelty-seeking traits in humans. J. Neurosci. 2008 Dec 12/31/2008; 28(53): 14372-8. PMID: 19118170, PMCID: PMC2748420, PII: 28/53/14372, DOI: 10.1523/JNEUROSCI.2423-08.2008, ISSN: 1529-2401.

Cowan RL, Roberts DM, Joers JM. Neuroimaging in human MDMA (Ecstasy) users. Ann. N. Y. Acad. Sci. 2008 Oct; 1139: 291-8. PMID: 18991874, PMCID: PMC2677829, PII: NYAS1139007, DOI: 10.1196/annals.1432.007, ISSN: 1749-6632.

Cowan RL, Wood J, Dietrich MS, de B Frederick B, Lukas SE, Renshaw PF. Differential effects of D-amphetamine on red and blue light-induced photic activation: A novel BOLD fMRI assay of human dopamine function. Synapse. 2008 Apr; 62(4): 268-72. PMID: 18240321, DOI: 10.1002/syn.20491, ISSN: 0887-4476.

Cowan RL, Bolo NR, Dietrich M, Haga E, Lukas SE, Renshaw PF. Occipital cortical proton MRS at 4 Tesla in human moderate MDMA polydrug users. Psychiatry Res [print-electronic]. 2007 Aug 8/15/2007; 155(3): 179-88. PMID: 17574394, PMCID: PMC2132656, PII: S0925-4927(07)00035-2, DOI: 10.1016/j.pscychresns.2007.01.008, ISSN: 0165-1781.

Cowan RL. Neuroimaging research in human MDMA users: a review. Psychopharmacology (Berl.) [print-electronic]. 2007 Jan; 189(4): 539-56. PMID: 16847678, DOI: 10.1007/s00213-006-0467-3, ISSN: 0033-3158.

Cowan RL, Haga E, deB Frederick B, Dietrich MS, Vimal RL, Lukas SE, Renshaw PF. MDMA use is associated with increased spatial BOLD fMRI visual cortex activation in human MDMA users. Pharmacol. Biochem. Behav [print-electronic]. 2006 Jun; 84(2): 219-28. PMID: 16782178, PII: S0091-3057(06)00121-3, DOI: 10.1016/j.pbb.2006.04.024, ISSN: 0091-3057.

Schiffer F, Mottaghy FM, Pandey Vimal RL, Renshaw PF, Cowan R, Pascual-Leone A, Teicher M, Valente E, Rohan M. Lateral visual field stimulation reveals extrastriate cortical activation in the contralateral hemisphere: an fMRI study. Psychiatry Res. 2004 May 5/30/2004; 131(1): 1-9. PMID: 15246450, PII: S0925492704000198, DOI: 10.1016/j.pscychresns.2004.01.002, ISSN: 0165-1781.

Cowan RL, Lyoo IK, Sung SM, Ahn KH, Kim MJ, Hwang J, Haga E, Vimal RL, Lukas SE, Renshaw PF. Reduced cortical gray matter density in human MDMA (Ecstasy) users: a voxel-based morphometry study. Drug Alcohol Depend. 2003 Dec 12/11/2003; 72(3): 225-35. PMID: 14643939, PII: S037687160300231X, ISSN: 0376-8716.

Cowan RL, Frederick BB, Rainey M, Levin JM, Maas LC, Bang J, Hennen J, Lukas SE, Renshaw PF. Sex differences in response to red and blue light in human primary visual cortex: a bold fMRI study. Psychiatry Res. 2000 Dec 12/22/2000; 100(3): 129-38. PMID: 11120440, PII: S0925492700000743, ISSN: 0165-1781.

Cowan RL, Sesack SR, Van Bockstaele EJ, Branchereau P, Chain J, Pickel VM. Analysis of synaptic inputs and targets of physiologically characterized neurons in rat frontal cortex: combined in vivo intracellular recording and immunolabeling. Synapse. 1994 Jun; 17(2): 101-14. PMID: 7916489, DOI: 10.1002/syn.890170206, ISSN: 0887-4476.

Cowan RL, Wilson CJ. Spontaneous firing patterns and axonal projections of single corticostriatal neurons in the rat medial agranular cortex. J. Neurophysiol. 1994 Jan; 71(1): 17-32. PMID: 8158226, ISSN: 0022-3077.

Cowan RL, Wilson CJ, Emson PC, Heizmann CW. Parvalbumin-containing GABAergic interneurons in the rat neostriatum. J. Comp. Neurol. 1990 Dec 12/8/1990; 302(2): 197-205. PMID: 2289971, DOI: 10.1002/cne.903020202, ISSN: 0021-9967.