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- ItemAn Ontogenetic Profiling of Object Recognition Tasks in the Rodent Brain(2022) Rodríguez Quintero, José E.; Robinson-Drummer, PatreseIn Neuroscience, learning and memory is an area of expansive and vital research, with an abundance of implications to our daily lives, education, development, and more. In our developmental neuroscience lab with Dr. Patresse Robinson-Drummer, we explored the question behind learning and memory behaviors corresponding to regions of activation in the brain. During development, animals' capacity for learning and memory change. Researchers in this area are interested in studying what brain regions are involved in learning and memory mechanisms, such as an animals' ability to recognize and remember an object. For this purpose, recognition memory tasks such as Object Recognition, Object location and Object-in-Place can be useful because they provide insight into a rodent's ability to learn and remember in different ways. This kind of learning is called incidental learning and involves acquiring information unintentionally during an activity and is often measured in rodents using object recognition tasks that capitalize on their natural tendency to explore novel objects in their environments. All of these tasks emerge at different ages and require different brain regions but it's not clear whether these same regions are needed during development or if the emergence of the behavior aligns with functional correlates of regional activity. We are beginning to tackle these questions starting with adolescent animals. What we understand so far is that the perirhinal cortex is involved in object recognition, the hippocampus is involved in object location, and the medial prefrontal cortex is involved in object-in-place. At postnatal day 28, animals were randomly assigned to either be trained in one task or to a control group of habituation only animals. After completing the task, the animals remained in their cages for 90 minutes and were then sacrificed in order to collect brain slices and conduct immunohistochemistry and DAB-Sonicate for c-FOS staining. The slices were then captured as images and analyzed using Image J FIJI and Jamovi Stats. Results showed that for OR and OiP, but not for OL, animals' novelty score was significantly above chance (0.80 and 0.69, respectively). However, our investigation was unable to find a correlation in adolescent PD28 rats between recognition and location tasks and the perirhinal cortex of the brain. Although the Prh exhibited c-Fos activation, a protein marker that suggests learning and memory processes in the brain occurred, the difference to our control animal's c-Fos expression was not significant. This pilot lab was able to develop protocols for the immunohistochemistry and DAB-Sonicate for the c-Fos staining as well as a standardized protocol for assessing c-Fos count in Image J for the perirhinal cortex and hippocampus. The ongoing plan for this developmental neuroscience lab will be attempting to reproduce these assays across 3 more developmental ages, with the project goal aiming to create an ontogenetic profiling of the rodent brain and the corresponding regions of activation.
- ItemMind Wandering: Effects on Mood and Attention(2022) Blossom, Sarah; Compton, Rebecca J. (Rebecca Jean)The present study investigated the relationship between mind wandering, mood, and EEG neural correlates of attention. Using a mood induction design, positive and negative moods were induced in participants prior to a sustained attention to response task (SART). Thought probes and retrospective questionnaires were employed to measure quantity and type of mind wandering. Overall, this study found that negative moods were more associated with overall mind wandering and reduced P300 amplitudes—an index of attention—at the P3, PZ, and P4 sites indicating perceptual decoupling. Individual differences in positive and negative moods prior to the SART were found to be associated with deliberate mind wandering and overall mind wandering, respectively. Change in mood was not found to be associated with deliberate mind wandering. These results provide more insight into the relationship between mind wandering and mood while adding a novel EEG relationship between negative mood induction and reduced P300 to the literature.
- ItemThe Impact of Progesterone and Estrogen Withdrawal via a Hormone-simulated Pseudopregnancy Model on ΔFosB Expression in the Nucleus Accumbens and Anxiety- and Compulsive-like Behavior in Female Mice(2022) Corbin, Jaclyn; Been, LauraThroughout pregnancy, ovarian hormones fluctuate dramatically. The rapid decrease of estradiol and progesterone during birth specifically have been implicated in a variety of mood and anxiety disorders. The current study investigates the effects of hormone withdrawal on changes in anxiety-like and OCD-like behaviors by using an old and modified hormone simulated pseudopregnancy (HSP) model in C57Bl/6 adult female mice. These models involved ovariectomized mice and providing daily hormone injections of either estradiol or estradiol and progesterone to mimic the hormones produced during pregnancy and the postpartum period. Of the mice only receiving estradiol (n=16), they were split into two groups based on whether or not they continued to receive estradiol injections throughout the postpartum period. Similarly, the subjects receiving estradiol and progesterone were also split into two groups (n=14) based on whether or not they continued to receive estradiol and progesterone or not throughout the postpartum period. It was hypothesized that the animals that stopped receiving hormone injections in the postpartum period would display more anxious behavior in an open field test and elevated plus maze test. It was also predicted that these animals would display more compulsive-like behavior in a marble burying assay. Researchers examined ΔFosB, a marker of neural plasticity within the nucleus accumbens (NAc), a brain region implicated in mood and anxiety disorders, to determine correlations between the NAc, hormone fluctuations, and behavior. We hypothesized that we would see a correlation between increased anxiety and compulsive-like behavior in the hormone withdrawn mice with increased ΔFosB expression in the NAc. There was no significant impact of hormone withdrawal on behavioral assays, but there was a significant increase in ΔFosB expression in the NAc core of estradiol and progesterone sustained mice. There were also significant increases in locomotion in the groups receiving hormones throughout the postpartum period. Future research should focus on the role of ΔFosB expression in mood disorders related to the postpartum period using this new HSP model.
- ItemDopamine Deficiency Predicts Pain: Toward A Novel Framework for the Neurophysiological Classification and Treatment of Chronic Pain(2022) Herman, Arielle F.; Robinson-Drummer, Patrese; Boltz, MarilynChronic pain is a widespread issue which strips millions of people of their agency, and bears devastating and often debilitating lifelong consequences for mental and physical wellbeing. It is also one of the largest burdens on socioeconomic welfare, costing the United States government an estimated $635 billion each year in medical expense and lost productivity. Although its pathophysiological mechanisms are far from elucidated, research spanning the past several decades has revealed a number of significant neurobiological correlates and theoretical frameworks which have yet to escape the enclosure of scientific journals to enter both the clinic and public awareness. It is generally accepted that the treatment of chronic pain is somewhat of a medical conundrum, with few chronic pain patients experiencing long-term relief, and many encountering interpersonal frustration and systemic roadblocks in clinical care. In line with chronic pain's status as a public health crisis, a great deal of literature highlights the urgency for new targets in pain management and prevention. Many published studies and institutional reports even provide detailed protocol for the implementation of higher-efficacy treatment methods for a wide array of conditions. In other words, there already exists a substantial pool of scientific insight which, if extended to translational research, could decrease morbidity and improve quality of life for many individuals, some of whom may be suffering unnecessarily or excessively, in a medical system that cannot provide for their clinical needs, often prescribing treatments designed for acute injuries to those who live for years with an elusive chronic syndrome. As a result, people's lives are excessively devastated by pain conditions which could be better managed, mitigated, or entirely prevented. Among scattered literature originating from a range of perspectives, one set of relationships emerges as critically important, with expansive implications for many areas of pain research, as well as for those who suffer with chronic pain. However, these disparate findings are yet to be integrated, and are therefore largely unknown, and alarmingly under-researched. A close examination of decades of research that has remained largely under the radar reveals a significant contribution of the state of dopaminergic neurotransmission to the mechanisms which underlie pain chronification. This comprehensive review synthesizes research in pharmacology, neurophysiology, psychiatry, and etiology in an effort to delineate the evidence for dopamine dysfunction as a common mechanism in the development of chronic pain. This includes documentation of correlational data revealing its prevalence, neurophysiological findings demonstrating its essential role in the homeostasis of pain-processing circuitry, as well as clinical evidence of the pervasive downstream effects and predispositions consistently observed with an imbalance of this system. By triangulating a number of neurophysiological mechanisms which are rarely considered in tandem, this paper highlights a critical shortcoming in the current literature on chronic pain. Integration of this widely overlooked research ultimately points to significant new targets for the clinical intervention, prevention, and reversal of chronic pain conditions, under a novel framework which could advance the current understandings about the fundamental nature of pain.