Post-Traumatic Stress Disorder (PTSD) is one of the most common mental disorders in the world. People with PTSD often have difficulty managing time or have witnessed a traumatic event in the past. PTSD is also associated with memory issues which are characterized by intrusive memories that can cause re-experience aspect of the traumatic event. Through the use of computational models, we aim to investigate the differences in memory retention in spaced vs massed practice presentations. We hypothesize that mass practice will lead to less accuracy in recognition and less intrusive thoughts during retention. Through recruiting healthy adult participants with no history of PTSD or other stress-related psychiatric disorders we get a base data avoiding discrepancies. Participants view visual stimuli as images, either neutral or triggering which are presented in pseudo-order and are asked to rate them based on their valence ranging from neutral to extremely negative. The images are presented under two conditions: mass and space presentation. For spaced presentation, different versions of the triggering image category are presented in no particular order with neutral and filler images in between. For massed presentation, all versions of the triggering image category are presented one after the other with no neutral or filler images in between. 24 hours after the initial presentation of the images, participants are tested on memory retention in the form of image recognition. Participants are asked about the difficulty of recalling the image and how often they think about the image. Having collected data during AUT 24, we were able to understand there is a correlation present between memory retention in mass and spaced recognition in terms of traumatic and non-traumatic events. By collecting data through WIN 25, we will have greater accuracy in terms of significant data.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that affects millions of people. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive stimulation typically used in psychiatric conditions such as depression and anxiety. rTMS works by using an electric current to generate a transient magnetic field, depolarizing neurons in a target region and creating lasting changes in brain connectivity via synaptic plasticity. Patients with AD show disruptions in the Default Mode Network (DMN), a network of brain regions typically active during rest and crucial for memory consolidation. We hypothesize that strengthening the DMN through rTMS targeted at the left Brodmann 8AV region, selected for being an easily accessible node of the DMN, will improve memory in AD patients. To test this hypothesis, we are conducting a single-blind, single-arm, randomized cross-over trial of rTMS on early-stage AD patients over a 12 week period with week 1 where we scan for the 8AV region via MRI, during week 3 and 8 being the placebo or treatment week. We measure our primary outcome of the participants’ speed of forgetting —a novel index of memory function—through an individualized, adaptive memory test. To eliminate potential confounding variables, we also measure depression and anxiety symptoms during the 1st, 8th and 12th week of the study. Additionally, functional MRI scans will be analyzed for potential structural or functional differences caused by treatment. Preliminary results from our initial participants have shown promising improvements, and we are hopeful that similar outcomes will be observed in the remaining participants. Successful results would provide a novel target for AD treatment using rTMS, and support further investigation of rTMS as a viable treatment option.

Changing patterns of human land use near coastal zones have increased the abundance of aquatic habitats where mosquito and midge larvae develop. Salt-tolerant species, such as Aedes togoi mosquitoes and Dicrotendipes enteromorphae midges, have evolved distinct anatomical and physiological mechanisms that allow them to thrive in saltwater environments while also being able to develop in freshwater. While much is known about how freshwater-confined species maintain salt and water homeostasis (i.e. osmoregulation) in dilute freshwater, these processes remain largely unexplored in salt-tolerant species. The main goal of this research was to describe and compare the osmoregulatory strategies of Ae. togoi and D. enteromorphae larvae reared in seawater and freshwater, focusing on how they maintain ion and water balance in saline conditions. Based on information from other salt-tolerant insects, I hypothesized that the rectum of these species is the main organ that excretes salts and will have higher expression of ion pumps compared to other osmoregulatory organs of the larvae. This increased expression would support the secretion of hyperosmotic (salty) urine, a critical adaptation for survival in saltwater. Using immunohistochemistry and fluorescence microscopy, I localized key ion-transport pumps within the rectum and other osmoregulatory organs of Ae. togoi and D. enteromorphae larvae. I identified a high expression of Na⁺/K⁺-ATPase (sodium/potassium pump), and V-type H⁺-ATPase (proton pump) enriched in the anal gills, renal tubules, and the rectum. My findings suggest that the coordinated function of many osmoregulatory organs, and not just the rectum, allows for salt-secretion by marine insects, and this establishes an initial framework of cellular mechanisms among marine insects. This research has implications for predicting future species distributions with rising sea levels, as well as the potential to identify novel targets to control salt-tolerant mosquito populations to mitigate disease transmission in coastal regions.

Neotrypaea californiensis, or burrowing shrimp, is a native pest for oyster growers in Washington. The shrimp create networks of interconnected burrows that displace and liquify sediment, suffocating oysters. The pesticide carbaryl was used for decades to effectively control shrimp populations. More recently, the Environmental Protection Agency (EPA) deemed carbaryl an environmental hazard, leading to a vital need for a shrimp control method with minimal non-target effects. Very little is known of the physiology of shrimp that allows them to tolerate environmental extremes. My study aims to understand the tolerance of Netotrypaea californiensis to high concentrations of salts that challenge their ability to regulate internal ions, pH, and metabolic wastes. Using a laboratory-based system whereby shrimp burrow in 6 inch deep sediment in seawater, my research findings revealed that the addition of high concentrations of sodium bicarbonate (NaHCO₃) caused shrimp mortality while high concentrations of regular sea salts did not. This suggested that an ionic imbalance—high levels of sodium and reduced levels of chloride—may be causing shrimp death. To investigate, I collected the gills, a critical organ that regulates systemic ion levels, of shrimp after NaHCO₃ exposure and quantified the abundance and localization of key ion pumps using Western blotting, immunohistochemistry and confocal microscopy. I found a significantly higher expression of Na⁺/K⁺ pumps in the gills with NaHCO₃ exposure, suggesting a major ion-regulatory disturbance caused by NaHCO₃. These data will expand our understanding of how salts that cause ionic imbalance in seawater can disrupt the internal levels of ions that are critical for most biological processes. Findings will be disseminated to Washington oyster growers to aid in the management of their crop.

The external fertilization and transparent embryos of zebrafish make them an informative model of vertebrate embryonic development from the 1-cell stage. In this study, we examine the impact of de novo GTP synthesis on the formation of the embryonic somites, which are embryonic cells which develop into segmented blocks of muscle that run the length of the body. We hypothesize the de novo GTP synthesis is required for the correct patterning of somite borders in zebrafish embryos, and that this process facilitates the formation of a vertebrate body plan. Inosine monophosphate dehydrogenase 2 (IMPDH2) is the enzyme which catalyzes the conversion of inosine monophosphate (IMP) towards the de novo synthesis of GTP instead of ATP. To test the impact of de novo GTP synthesis on somite formation, we inhibited IMPDH2 function with mycophenolic acid (MPA) both before and after somite formation began. MPA caused stronger defects in the somite morphology and embryonic body shape when added to embryos before somite formation began, earlier in development. We performed in situ hybridization against xirp2a to assess the effect of inhibiting IMPDH2 function on the formation and patterning of the somite borders. MPA treatment decreased the definition of somite borders we could observe in the posterior tail. Inhibiting IMPDH2 with MPA produced somites with smooth, round borders instead of the chevron-shape typical of zebrafish. We next conducted immunohistochemistry against IMPDH2 to examine the expression and localization of this enzyme in embryonic cells when GTP conditions are low. In MPA-treated embryos, we observed increased expression of IMPDH2 across the entire embryo. We will next explore how GTP abundance affects activity of the clock, a mechanism which synchronizes gene expression of embryonic cells.

Hyalella azteca are freshwater amphipod crustaceans abundantly found throughout North America and are frequently used in toxicology for water and sediment toxicity testing. As freshwater bodies change due to anthropogenic climate change, understanding chronic, sublethal impacts to aquatic life is critical. Amphipods are known to have a higher tolerance to heavy metals (i.e. Cu²⁺) and road salt (i.e. NaCl) compared to other aquatic invertebrates, however, these contaminants may have subtle, sublethal consequences on their ability to smell and detect chemical cues for survival and reproduction. This research identifies the combined impacts of environmentally relevant levels of Cu2+ and NaCl, on the olfactory system and olfactory-related behaviors of H. azteca. H. azteca underwent acute 96 hour exposure to control, Cu2+ (30 µmol/L), and combined Cu2+ (30 µmol/L) and NaCl (5 ppt) contaminated freshwater. I recorded daily measurements of survival, and utilized qPCR to examine changes in the expression of key olfactory genes that we predicted would be modulated in response to these multiple stressors. I assessed the olfactory-associated foraging behavior to determine changes in their detection of an attractive food cue when exposed to Cu2+ and NaCl, which would indicate olfactory impairment. Preliminary results show that amphipod survival is not impacted by Cu2+ and NaCl contamination but changes to their olfactory system occur. Therefore, U.S. Environmental Protection Agency water quality standards for heavy metals and salt may not mitigate long-term, sublethal effects on aquatic animal populations as it relates to this important sensory modality.

Certain species exhibit the remarkable ability to regenerate their appendages, a process that requires complex metabolic pathways to facilitate the cellular proliferation needed to regrow tissue. Among these species, Xenopus tropicalis, the Tropical Clawed Frog, serves as a great model for regeneration studies because of its transient regenerative capacity. X. tropicalis tadpoles exhibit the ability to regenerate their tails, but this capability is gradually lost after metamorphosis. This unique characteristic allows for direct comparison of regenerative and non-regenerative processes within the same species. Previous work from the Wills lab indicates that genes encoding the enzymes of the pentose phosphate pathway (PPP), which generates precursors of biosynthetic molecules such as nucleotides and lipids, are highly expressed during tadpole tail regeneration. Although tail regeneration has been well studied, the variation in hind limb regenerative capacity across developmental stages and the metabolic pathways involved remains unclear. Hence, I performed a live imaging study to determine the developmental progression of hind limbs and assess their regenerative potential. This data suggests a decrease in success as the tadpole gets older. Immunohistochemistry staining of mitotic cells in developing limbs shows that proliferating cells decline as regeneration competency decreases. I hypothesized that genes for the PPP enzymes would also be expressed during successful limb regeneration, which was confirmed by in-situ hybridization. Together, these findings indicate that the regenerative capacity in limbs of X. tropicalis is stage-dependent and that PPP genes are expressed during all stages of regenerative capacity. This provides insights into the role of metabolic reprogramming in appendage regeneration, with the potential for translating it into non-regenerative species like mammals.

Overgeneral Autobiographical Memory (OGM) is a common symptom of depression and Post-Traumatic Stress Disorder (PTSD). Instead of remembering specific details, individuals with OGM can only describe past events from their lives in general terms. The "trauma hypothesis" suggests that OGM emerges because individuals suffering from PTSD tend to reduce the number of details they retrieve about their memories to avoid remembering their trauma. However, this hypothesis does not fully explain how this avoidance is learned, or why avoidance spreads from traumatic memories to all autobiographical memories. To this end, we propose a computational model of OGM that integrates theories of memory retrieval and trauma with reinforcement learning. In this model, multiple episodic memories are nodes in an interconnected network, and memories are retrieved when visiting that node in the network. The more nodes that are visited, the more detailed that autobiographical recall will be. On the other hand, visiting more nodes comes with an increased risk of encountering a traumatic memory, which comes with negative emotional valence. The decisions about whether to visit another node or terminate the retrieval process are made using reinforcement learning, which takes actions based on predicted outcomes. By obtaining a greater understanding of OGM through this model, we hope to improve treatments for PTSD that specifically targets its effects on memory. 

Patient-provider communication impacts healthcare outcomes, but assessing the quality of interactions manually takes time and effort. This project explores the automatic assessment of patient-provider interactions using Language Style Matching (LSM). LSM scores the linguistic similarity of function words between conversational partners (e.g.,  pronouns, articles) from 0 (low matching) to 1 (perfect matching), reflecting how in-sync partners are. Past research establishes LSM as a marker for the quality of interpersonal communication that predicts how likely romantic relationships are to last, but has not been explored for clinical interactions. We (CL, NE) applied LSM to investigate how well patients and providers matched each other's speaking styles for insights into the quality of clinical interactions. We used Linguistic Inquiry and Word Count (LIWC), a software program for LSM analysis of transcripts. Using LIWC, we analyzed the transcripts of 108 simulated visits between 54 primary care providers and four standardized patients. We used descriptive statistics to characterize LSM across visits. Our initial findings show that LSM scores range from 0.77 to 0.94 ( mean=0.86, SD=0.03) which is similar to prior research where most verbal conversations fall between 0.83 and 0.94. These findings show that on average providers and patients tend to match each other in their speaking style at a level similar to typical conversations. However, we identified some outliers that fall below 0.83 threshold. Opportunities for future work include thin-slice analysis of the transcripts to understand how LSM scores change throughout a visit and comparing LSM scores to self-reported survey data about visit quality. ​​We hope to further investigate this efficient marker of conversational quality as LSM has the potential to characterize the quality of clinical interactions without the time and effort required of traditional manual approaches.

This study investigates the Namonuito region of Micronesia to determine whether the many guyots and atolls in this region contain specific slope conditions suitable for cobalt crust growth. This project also investigates whether there is a relationship between suitable zones and general bathymetry. The primary research focused on NAM-2 Atoll and Enterprise, Essex, and Namonuito Guyots. After collecting multibeam and sub-bottom data, the slopes were analyzed for slope angle, optimal slope distribution and composition. Then the results were compared with each other to determine if there are any similarities or correlations. Among all the guyots it was found that almost all the optimal zones were found in gullies, ridge slopes, and at the bottom of areas that experience slope failures. However, there isn’t a clear correlation between mean slope angle, optimal slope distribution and slope face orientation. In addition, sub-bottom data showed that almost all the guyots northern slopes were covered by a single thick pelagic layer, while the southern slopes of Namonuito and Enterprise contained thin pelagic layers with zones of exposed hard substrate. NAM-2 Atoll also was entirely covered in a single thick pelagic layer. Overall, by conducting a geomorphology and sub-bottom comparison test it is possible to narrow down locations of interest that can be further surveyed. The implications of cobalt crust research are that cobalt crusts are another natural source of cobalt which is becoming increasingly difficult to obtain on land. If the Namonuito region contains a large cobalt crust and the cobalt crusts can be extracted, it could have a huge impact of global technology and manufacturing industries.

Humans have limited regenerative capabilities, providing incentive to study other natural models of regeneration to make advances in the field of regenerative medicine. In response to injury, species including Xenopus tropicalis employ cellular mechanisms to replenish lost tissue, a process that has high metabolic demands. Depending on their developmental stage, X. tropicalis tadpoles exhibit different regenerative capabilities after tail amputation, posing them as a unique model system. Three-day-old tadpoles (NF stage 41) are able to regenerate their tails completely after injury, but transiently lose this ability during what is known as the refractory period. However, they soon regain regenerative capabilities in the tail and in the developing hind limb before permanently losing them during metamorphosis. Previous work by the Wills lab has determined that the pentose phosphate pathway (PPP) is required for successful tail regeneration in stage 41 tadpoles, but leaves open the question of whether the PPP remains significant at subsequent regenerative stages and structures. Here I test the hypothesis that the PPP continues to facilitate appendage regeneration in post-refractory tadpoles. To functionally test the requirement of the PPP in post-refractory tail regeneration, I performed pharmacological inhibition of g6pd, a key enzyme in the PPP, during tail regeneration. To assess regeneration quality, I developed a pipeline using FIJI ImageJ and R to quantify metrics of regenerative success such as tail area and length. Using this framework, I found that post-refractory tadpoles had diminished regenerative success under PPP inhibition similar to stage 41 tadpoles. These results suggest that the PPP is required at all stages of tadpole tail regeneration and will provide a more comprehensive understanding of metabolism during regeneration, a potentially beneficial insight for research in wound-healing initiatives in mammals.