The Wassum lab uses behavioral paradigms, coupled with neuropharmacology and neurochemical monitoring techniques, to unravel the neural mechanisms and systems that are responsible for motivated learning and decision-making. They are also investigating how disorders, such as addiction, defined by maladaptive decision-making, result in pathologies of motivated behavior.
Basolateral amygdala rapid glutamate release encodes an outcome-specific representation vital for reward-predictive cues to selectively invigorate reward-seeking actions Malvaez M, Greenfield VY, Wang AS, Yorita AM, Feng L, Linker KE, Monbouquette HG, Wassum KM. Scientific Reports (2015).
Probing the Neurochemical Correlates of Motivation and Decision Making Wassum KM, Phillips PEM. ACS Chemical Neuroscience (2015) 6(1), 11-13.
Inflated Reward Value in Early Opiate Withdrawal. Wassum KM, Greenfield, VY, Linker KE, Maidment NT, Ostlund SB. Addiction Biology (2014)
Phasic Mesolimbic Dopamine Signaling Encodes the Facilitation of Incentive Motivation Produced by Repeated Cocaine Exposure. Ostlund SB, LeBlanc KH, Kosheleff AR, Wassum KM, Maidment NT. Neuropsychopharmacology (2014) 39, 2441-2449.
Phasic mesolimbic dopamine release tracks reward seeking during expression of Pavlovian-to-instrumental transfer. Wassum KM, Ostlund SB, Loewinger GC, Maidment NT. Biological Psychiatry (2013) 73(8):747-55
Electrochemically-deposited iridium oxide reference electrode integrated with an electroenzymatic glutamate sensor on a multi-electrode array microprobe. Tolosa VM, Wassum KM, Maidment NT, Monbouquette HG. Biosensors and Bioelectronics (2013) 42: 256-60
Transient extracellular glutamate events in the basolateral amygdala track reward seeking actions. Wassum KM, Tolosa VM, Tseng TC, Balleine BW, Monbouquette HG, Maidment NT. J. Neurosci. (2012) 32(8): 2734-2746.
Phasic mesolimbic dopamine signaling precedes and predicts performance of a self-initiated action sequence. Wassum KM, Ostlund SB, Maidment NT. Biol. Psychiatry Priority Communication (2012) 71(10):846-54.
Wassum KM, Ostlund SB, Balleine BW, Maidment NT (2011). Differential dependence of Pavlovian incentive motivation and instrumental incentive learning processes on dopamine signaling. Learn Mem, 18(7):475-83.
Wassum KM, Cely IC, Balleine BW, Maidment NT. (2011) Mu, not delta or kappa opioid receptors in the basolateral amygdala are necessary for learning about increases, but not decreases in incentive value. J. Neurosci, 31(5): 1583-1590.
Ostlund SB, Wassum KM, Murphy NP, Balleine BW, Maidment NT. (2011) Extracellular dopamine levels in striatal subregions track shifts in motivation and response cost during instrumental conditioning. J. Neurosci, 31(1): 200-207.
Wassum KM, Cely IC, Ostlund SB, Maidment NT, Balleine BW. (2009) Disruption of endogenous opioid activity during instrumental learning enhances habit acquisition. Neuroscience, 163(3): 770-80.
Wassum KM, Ostlund SB, Maidment NT, Balleine BW. (2009) Distinct opioid circuits determine the palatability and the desirability of rewarding events. Proc Natl Acad Sci USA, 106(30): 12512-7.