Dr. Kyle Frantz / Dr. Anne Murphy
Topic: Sexual Dimorphism in the Long-Term Effects of Neonatal Stress on Vulnerability to Opiates
Abstract:
Specific Aim 1: Test the impact of neonatal stress on acquisition of intravenous heroin self-administration in adult male and female rats. Early stress, caused by an adverse neonatal or childhood environment, is clearly associated with an increased susceptibility to substance abuse later in life. Previous studies examining potential mechanisms for this trajectory have focused on alcohol or psychomotor stimulant intake, leaving the effects of neonatal stress on opiate self-administration unknown. In addition, the potential sexually-dimorphic impact of neonatal stress on heroin self-administration has not been explored. In Aim 1, we will test the hypothesis that acquisition of heroin self-administration occurs faster and at a lower dose in female compared to male rats, and that this difference is exacerbated after neonatal injury. In the future, we will also test the hypothesis that neonatal injury increases the potency and efficacy of opiates as reinforcers to a greater degree in females than males, using fixed-ratio and progressive ratio schedules of reinforcement.
Specific Aim 2. Test the impact of neonatal stress on opioid receptor properties of the mesocorticolimbic reward circuit in adult male and female rats. Previous studies examining opiate receptor distribution in CNS reward sites have been conducted exclusively in males. Studies proposed in Aim 2 will test the hypothesis that the distribution and expression of opiate receptors are sexually dimorphic in CNS reward-associated substrates, and that these sex differences contribute to sex-based differences in opiate intake and abuse. In the future, we will also test the hypothesis that neonatal injury alters opiate receptor expression, thereby providing a neurobiological mechanism for the increased opiate intake in neonatally stressed animals.
Eric Vanman / David Washburn
Title: Functional Neuronimaging of Executive Functioning in Social Prejudice
Abstract:
Our long-term goal is to investigate the neural basis of prejudiced responses so that we can better understand their antecedents and consequences. The overall objectives for this project are to study prejudiced responses to both naturally occurring and artificially created social groups using continuous measures of emotion-related peripheral physiological activity and functional neuroimaging, and to relate these responses to cognitive (i.e., executive) functioning.
We have three specific aims:
(A) Investigate somatic markers for both naturally occurring and artificially created social groups using psychophysiological measures. We plan to create temporary, arbitrary groups in the laboratory. On subsequent visits to the laboratory, research subjects will either interact with or view members of their own group or the other. The artificial groups will be composed of racially diverse team members, so that responses to natural social categories can be studied as well. We expect that the physiological changes we observe for either the natural or artificial groups will be comparable, but will differ with respect to stereotypes, beliefs, and behaviors, due to differences in learning history.
(B) Explore the neural substrates of the somatic markers using functional neuroimaging . Based on recent work in neurology on the somatic basis of decision-making and in neuroscience on the neural substrates of prejudiced reactions, we expect the proposed research to lead to the development of a more comprehensive neuroscience model of social categorization and prejudice.
(C ) Examine the role of executive functioning in the self-regulation of prejudiced responses. Recent research in Nature Neuroscience has tentatively demonstrated that prejudiced individuals drain their executive functioning resources in the presence of an outgroup member. We plan to elaborate on this promising research by using a battery of tests that measure cognitive functioning in a more diverse sample and relate these measures to some of the neural substrates identified by fMRI.
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