Please visit my lab website at http://mroitman.wix.com/mroitman.
Ph.D., University of Washington, Seattle, WA
B.A., Cornell University, Ithaca, NY
Motivated behavior, reward, aversion, feeding, obesity, drug addiction, dopamine, limbic circuitry, basal ganglia
Statement of Research Interests:
My lab is interested in determining the neural basis of normal motivated behaviors including feeding and drinking as well as maladaptive behaviors such as drug-taking and the over-consumption associated with obesity. The nucleus accumbens and the neurotransmitter dopamine are critical brain substrates involved in motivated behavior including feeding and drug-taking. They appear to be vital to reward-related learning as well. Since the nucleus accumbens accesses motor-related structures it is well suited to modulate behavior based on changes in motivational state and learned associations. Our research seeks to determine how signaling in the nucleus accumbens is altered in response to changes in motivated state and learned associations. To accomplish this, we employ two state-of-the-art recording techniques combined with detailed behavioral analyses. Electrophysiological recordings of many single neurons and electrochemical recordings of dopamine release in the nucleus accumbens are made in real-time during behavior. These two recording techniques are performed while rats taste rewarding and aversive stimuli or are working to obtain food or drug rewards. Learned associations are manipulated by pairing a rewarding taste with illness thereby rendering it aversive in the future. Motivational state is altered by food or water restriction or by the delivery of hormones or neuropeptides to mimic need-states or satiety. Finally, we are interested in whether the propensity to take drugs, such as cocaine, can be altered through the delivery of hormones or neuropeptides that affect food intake. This program or research will shed considerable light on human disorders of motivation such as obesity and drug-addiction.
Figure 1. Recordings made in awake and behaving rats. Top: Color representation of dopamine (seen as the green features) signaling in real-time using fast-scan cyclic voltammetry. Left, example. Right, time-averaged over 30 minutes. Bottom: Simultaneous recordings of many individual neurons in the nucleus accumbens and electromyographic recording of the anterior digastric muscle.
McCutcheon JE, Ebner SR, Loriaux AL & Roitman MF (2012). Encoding of aversion by dopamine and the nucleus accumbens. Frontiers in Neuroscience. [Epub ahead of print] (PDF)
Sinkala E, McCutcheon JE, Schuck MJ, Schmidt E, Roitman MF & Eddington DT (2012). Electrode Calibration with a microfluidic flow cell for fast-scan cyclic voltammetry. Lab on a Chip. 12:2403-2408. (PDF)
McCutcheon JE, Beeler JA & Roitman MF (2012). Sucrose-predictive cues evoke greater phasic dopamine release than saccharine predictive cues. Synapse. 66:346-351. (PDF)
Owesson-White CA, Roitman MF, Sombers LA, Belle AM, Keithley RB, Peele JL, Carelli RM & Wightman RM (2012). Sources contributing to the average extracellular concentration of dopamine in the nucleus accumbens. Journal of Neurochemistry. 121:252-262. (PDF)
Brown HD, McCutcheon JE, Cone JJ, Ragozzino ME & Roitman MF (2011). Primary food reward and reward-predictive stimuli evoke different patterns of phasic dopamine signaling throughout the striatum. European Journal of Neuroscience. 34:1997-2006. (PDF)
Loriaux AL, Roitman JD & Roitman MF (2011). Nucleus accumbens shell, but not core, tracks motivational value of salt. Journal of Neurophysiology. 1061537-1544. (PDF)
Ebner SR, Roitman MF & Chartoff, EH. (2010) The kappa opioid receptor agonist salvinorin A decreases motivation and phasic dopamine release in the nucleus accumbens in rats. Psychopharmacology. 210(2):241-52. (PDF)
Roitman, JD & Roitman, MF (2010). Risk-preference differentiates orbitofrontal cortex responses to freely chosen reward outcome in rats. European Journal of Neuroscience. 31(8):1492-500. (PDF)
Roitman, MF, Wheeler, RA, Wightman, RM & Carelli RM (2008) Real-time chemical responses in the nucleus accumbens differentiate rewarding and aversive stimuli. Nature Neuroscience, 11: 1376-1377. (PDF)
Day, JJ, Roitman, MF, Wightman, RM & Carelli RM (2007) Associative learning mediates dynamic shifts in dopamine signaling within the nucleus accumbens. Nature Neuroscience, 10: 1020-1028. (PDF)
Roitman, MF (2006) Persistent hunger for sodium makes brain stimulation not so sweet: theoretical comment on Morris et al. (2006). Behavioral Neuroscience, 120, 744-747. (PDF)
Day, JJ, Wheeler, RA, Roitman, MF & Carelli, RM (2006) Nucleus accumbens neurons selectively encode reward prediction and Pavlovian approach behavior. The European Journal of Neuroscience, 23, 1341-1351. (PDF)
Wheeler, RA, Roitman, MF, Grigson, PS & Carelli, RM (2005) Single neurons in the nucleus accumbens track relative reward. International Journal of Comparative Psychology, 18: 320-332.
Roitman, MF, Wheeler, RA & Carelli, RM (2005) Nucleus accumbens neurons are innately tuned for rewarding and aversive taste stimuli, encode their predictors, and are linked to motor output. Neuron 45, 587-597. (PDF)
Stuber, GD, Roitman, MF, Phillips, PEM, Carelli, RM & Wightman, RM (2004) Rapid dopamine signaling in the nucleus accumbens during contingent and non-contingent cocaine administration. Neuropsychopharmacology doi:10.1038/sj.npp.1300619. (PDF)
Roitman, MF, Stuber, GD, Phillips, PEM, Wightman, RM & Carelli, RM (2004) Dopamine operates as a subsecond modulator of feeding. Journal of Neuroscience 24, 1265-1271. (PDF)
Office: 1042C BSB, MC 285