In the past decade, neuroscientists have been attempting to develop more efficient methods for identifying irregularities in the neural pathway system.This would allow better understanding and diagnosis of psychiatric and neurological disorders. Current research concludes that simple white matter fiber tracts can be identified reproducibly. However, regions with complex fiber orientations still lead to errors in the estimated connections due to lack of high resolution data. Diffusion Tensor Imaging (DTI) tractography is an MRI technique used to identify white matter fibers connecting different parts of the brain, based on the direction and magnitude of water diffusion. Our research proposes that by studying a unique high resolution dataset consisting of both submillimeter resolution DTI and micron resolution microscopy images stained for neurons in the human brain, we can identify these complex pathways. Using three standard graph-based algorithms (minimum spanning trees, Dijkstra’s algorithm, and Viterbi’s algorithm), we developed computational tools for estimating pathways between pairs of brain regions. We test the hypothesis that while minimum spanning trees will compute fastest, there will be a gap in accuracy when compared to microscopy data. We hypothesize that other algorithms are slower, but will match better with microscopy. Our platform will serve as a starting point for developing and validating novel tractography algorithms in the future.

Presenters Name: Joyane Eriom Presentation Field/Area(s): Neuroscience University/College Name: Baylor University Faculty Mentor Name: Lara Hwa Presentation Title: Neuronal markers of escalated sucrose drinking in C57BL/6J mice Sugar, or sucrose, plays a large role in our daily consumption and healthy functioning. However, overconsumption of sugar can be problematic, so preclinical studies are necessary to monitor the behavioral progression towards diseases. Previous research has shown that intermittent exposure to sucrose using rats can produce sugar bingeing behavior. This study compares intermittent access to 4% sucrose to continuous access to sucrose to elevate consumption levels in C57BL/6J mice. 24-hour sucrose preference and anxiety-like behavior will be measured after 12 intermittent or continuous days of drinking. During a final binge drinking day, brains will be collected for immunohistochemical c-Fos staining to measure neuronal activation in specific brain areas. Ongoing data suggest that mice given intermittent access to sucrose will escalate their voluntary sucrose drinking to higher levels than mice given continuous access. For brain site activation after a final sucrose binge, it is predicted that brain areas related to addiction and substance use, such as the prefrontal cortex, ventral tegmental area, amygdala, and dorsal raphe nucleus, may have higher c-Fos counts in the intermittent versus continuous access condition. Our studies suggest that binge-like sugar overconsumption can be modeled in mice by simply changing the schedule of availability. In addition to canonical brain sites involved in reward and the development of addiction, this experiment may reveal novel brain sites associated with sucrose binging. Ultimately, this research will have important implications for regulating junk food availability in vulnerable human populations.

Introduction: Bipolar disorder (BD) is associated with a high risk of suicide, and mortality studies have revealed that among psychiatric diagnoses, BD is perhaps associated with the highest suicide risk. Approximately, 90% of people who completed suicide meet the criteria for and had been diagnosed with a psychiatric disorder, primarily a mood disorder. Hindered stress response mechanisms have been shown to contribute to suicide risk. This study aims to target neural responses to stress to possibly render a potential strategy for identifying new treatment targets and improving suicide risk prediction. Although stress is known to play a major role in suicidal behaviors in individuals with BD, the nature and extent of its involvement remain unclear. Methods: Young adults with bipolar disorder & healthy control groups completed a modified version of the Montreal Imaging Stress Task, which includes a control math task and a stress math task condition. fMRI data were preprocessed with Statistical Parametric Mapping software (SPM12). Data were realigned, corrected for slice timing, coregistered to anatomical data, spatially normalized to the T1-weighted template image, and spatially smoothed. Objective: It is unclear if altered neural response involved in stress response in young adults with BD is associated with a higher risk for suicide behavior and thoughts (SBT). Therefore, it is critical to determine whether alterations in neural response to stress in young adults with BD have a significant relationship with a history of SBT and if these alterations can serve as a target for intervention to prevent further mortality.

A significant concern is the increase in weight gain given that obesity is a key risk factor for other conditions including heart disease and stroke. When presented a high fat/high sugar diet, rats will increase in intake and weight. This animal model provides an experimental analogy for overconsumption of calorie-dense foods that contribute to obesity in humans. Alternate day fasting involves cycles of feeding and fasting that have been shown to be effective for improving metabolic measures. Our group recently reported that rats that have free access to chow and a high energy diet (HE) show almost exclusive preference for HE food. In contrast, when rats are food deprived for 24 hours and presented with a choice between chow and HE diets, these rats (ADF) show lower HE diet preference driven by higher chow intake. This effect is more pronounced in male rats than female rats. Taste cues guide feeding and drinking behavior and begin with activation of receptors in the taste buds. Fungiform papillae (FP) taste buds are found on two thirds of the anterior tongue. Here, the number of taste buds between male and female rats maintained on an ADF or control schedule are compared. Both male and female ADF rats showed lower HE diet preference than controls. We hypothesize that ADF rats will show higher FP counts than controls and that males will show higher FP counts than females. These findings will provide better understanding of how taste buds change as a function of diet presentation schedule.

Psychological stress has been associated with increased risk of cardiovascular disease. Understanding how our cardiovascular system habituates to repeated stress may elucidate a potential pathway between psychological stress and cardiovascular disease. Acting as an extension to previous research, we had two main aims with this paper: 1) to see whether the four potential cardiovascular reactivity patterns can be observed (Hughes et al., 2018), and 2) whether specific combinations of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) reactivity can be seen (Brindle et al., 2016). Our data was gathered from a within-subjects design involving 445 participants (Mean (SD) age = 19.5 (1.3) years, 61.9% female, 66.4% Caucasian). The session consisted of two exposures to the same arithmetic stressor, with BP and HR recorded throughout. Multivariate cluster analyses were conducted to examine the relationship between BP and HR reactivity patterns and cardiovascular reactivity habituation patterns. We favored the five-cluster graph since it produced groups that showed varying combinations of cardiovascular stress reactivity without being overwhelming to the viewer. We were able to identify clusters as those outlined by Brindle et al. (2016), such as a cluster showing exaggerated BP with average HR response (which has been shown to have the greatest risk of hypertension). Although not all four of the proposed habituation patterns were seen in this analysis, expanding the number of clusters could provide insight to even more specific patterns. Future studies should include a more diverse race and age demographic.