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BACKGROUND Dopaminergic activity plays a role in mediating the rewarding aspects of abused drugs, including nicotine. Nicotine modulates the reinforcing properties of other motivational stimuli, yet the mechanisms of this interaction are poorly understood. This study aimed to ascertain the impact of nicotine exposure on neuronal activity associated with(More)
BACKGROUND The reinforcing effects of nicotine are mediated by brain regions that also support temporal difference error (TDE) processing; yet, the impact of nicotine on TDE is undetermined. METHODS Dependent smokers (n = 21) and matched control subjects (n = 21) were trained to associate a juice reward with a visual cue in a classical conditioning(More)
BACKGROUND Deficits in olfactory identification have been widely reported in patients with schizophrenia (SZ) and are associated with negative symptomatology. Adjunctive oxytocin delivered intranasally has been shown to improve some aspects of social cognition as well as positive and negative symptoms in patients with schizophrenia. Given the intranasal(More)
Behavioral and neuroplastic changes occurring in the development of addiction parallel those that occur in social bonding. This has led to speculation that drugs of abuse co-opt systems that subserve social attachment to shift attachment to drugs of abuse. Oxytocin, a neuropeptide that is important in social bonding, has been shown in rodents to decrease(More)
Previous reports on the functional effects (i.e., gain or loss of function), and phenotypic outcomes (e.g., changes in addiction vulnerability and stress response) of a commonly occurring functional single nucleotide polymorphism (SNP) of the mu-opioid receptor (OPRM1 A118G) have been inconsistent. Here we examine the effect of this polymorphism on implicit(More)
Agonists at the mu opioid receptor (MOR) are widely recognized for their effects on reward and pain. Although prior studies have attributed some of these effects to MORs on GABA neurons in the ventral tegmental area (VTA), recent studies have identified a region of particularly strong MOR immunostaining residing caudal to the VTA, in a region denoted the(More)
UNLABELLED The neural correlates of response to psychosocial stress and gender differences therein are difficult to model experimentally as this type of stressor is difficult to induce in a brain imaging environment. The Trier Social Stress Test (TSST), a behavioral paradigm that reliably induces moderate levels of stress was thus modified for the MRI(More)
The neuropeptide oxytocin functions as a hormone and neurotransmitter and facilitates complex social cognition and approach behavior. Given that empathy is an essential ingredient for third-party decision-making in institutions of justice, we investigated whether exogenous oxytocin modulates empathy of an unaffected third-party toward offenders and victims(More)
Individuals addicted to most chemical substances present with hypoactive dopaminergic systems as well as altered prefrontal white matter structure. Prefrontal dopaminergic tone is under genetic control and is influenced by and modulates descending cortico-striatal glutamatergic pathways that in turn, regulate striatal dopamine release. The(More)
Nicotine and tonic dopamine (DA) levels [as inferred by catechol-O-methyl tranferase (COMT) Val158Met genotype] interact to affect prefrontal processing. Prefrontal cortical areas are involved in response to performance feedback, which is impaired in smokers. We investigated whether there is a nicotine × COMT genotype interaction in brain circuitry during(More)