Current and Potential Projects

Along with students and collaborators, my lab is currently pursing several projects, and we plan to start some new lines of work this coming year.

Project Frameworks

Impact of stressors and individual variation on reproductive trade-offs: Current dogma suggests that stressors, and HPA axis hormones, promote fitness during challenging times by suppressing current reproduction and shifting resources and behaviors to survival or future reproductive efforts. Using this framework, several hypotheses predict that organisms will favor self-maintenance and future reproductive opportunities at the cost to current breeding. Under specific conditions, however, organisms are expected to invest more heavily in current reproduction and thus show a blunted response to stressors in order to protect reproductive effort (see Harris, 2020 for more); this trade-off often depends on an organism’s ecology, environment, and/or life history stage. My previous work has examined the role of paternal care and fatherhood in HPA axis function and reproduction in Peromyscus californicus; my current lab will expand on this to address how multiple stressors, both acute and chronic, impact behavior, fitness-, and survival-related measures, particularly during aging, using multiple species of Peromyscus. In wild populations, alterations in climate will likely result in changes to food and water availability, predation, habitat, temperature, and seasonal cues governing reproduction. Therefore, climate change could have profound impacts on organismal health and fitness, with threatened and endangered species being particularly vulnerable. Each of these climate-change-induced alterations could be a stressor and thus impact physiology, behavior, and influence life history trade-offs.

The role of threat and stress in anxiety, feeding, and risk-taking behavior: Threatening situations result in pronounced behavioral, cognitive, and emotional changes, responses which are presumably adaptive as they help organisms survive these events. In animals, for example, predators, or predator cues, can increase vigilance and hiding behaviors, and can disrupt feeding. While much is known about the impact of predators on prey behavior, less is known about how, exactly, prey animals’ detection of predator stimuli translates to rapid behavioral changes. Additionally, the physiological and behavioral parallels between prey response to predators and human response to threats has been recognized and it is hypothesized that these evolutionarily conserved threat responses play a role in human feeding, psychopathologies, internalizing disorders, and risk-taking behavior.

Stress, diet, cognitive function, and aging: Acute stress situations and short-term activation of the HPA axis is hypothesized to be adaptive as it helps organisms survive challenging situations and can enhance memory. Chronic stress and activation, however, can be problematic and can negatively impact health and survival. One specific variable that is highly impacted by stress is cognitive function. The relationship between stress and cognitive function is an inverted U - both very low and very high levels of stress, and glucocorticoid hormones, are associated with decreased cognitive function (inverted U hypothesis). Additionally, repeated stressor exposure and elevated glucocorticoids are associated with onset and progression of various diseases, including Alzheimer’s disease (see: glucocorticoid cascade hypothesis; vicious cycle of stress framework). Using human and animal studies, my lab is addressing the role of stress-responsive or -associated proteins (e.g., FKBP5, MR/GR, BDNF, ghrelin, insulin, endocannabinoids, inflammatory markers), life experiences (e.g., early-life stress, social housing, or maternal care), and other factors (e.g., sex, diet, caffeine) to explain why some individuals are more susceptible to stress-induced cognitive deficits than are others, and determine how these variables related to HPA axis activity, affective state, and cognitive function.

Currently Funded Projects

  1. Examining Effects of Respite and Individual Clinical Interventions on Biopsychosocial Outcomes in Informal Caregivers of Dementia Patients

    a. Funding: Garrison Family Foundation

    b. Collaborators: Dr. Jonathan Singer; TTU

    c. Species: humans

  2. Identity, stressors, and health-realted behaviors

    a. Funding: NIH, NIAAA

    b. Collaborators: Dr. Amelia Talley, TTU; Dr. Zachary Hohman, TTU; Dr. Andrew Littlefield, TTU

    c. Species: humans

  3. Reducing suicide risk among aging caregivers of persons with AD/ADRD: Adapting, implementing, and evaluating Dialectical Behavior Therapy skills training interventions.

    a . Funding: NIH, NIA

    b. Collaborators: Dr. Jonathan Singer, TTU; Dr. Sean Mitchell, TTU; Dr. Andrew Littlefield, TTU; Dr. Jason Van Allen, TTU; Dr. Megan Renna, University of Southern Missisppi

    c. Species: humans

Previously Funded Projects

  1. What is the role of tectal CRF in multisensory feeding-related behavior?

    a. Funding: NSF

    b. Collaborators: Dr. Jim Carr; TTU

    c. Species: Xenopus laevis

  2. What roles do diet, sex, and genotype play in the onset and development of Alzheimer’s disease pathophysiology, HPA axis function, and behavior?

    a. Funding: NIH (NIA; NCCIH)

    b. Collaborators: Dr. Paul Soto, Louisiana State University; Dr. Naima Moustaid-Moussa, TTU; Dr. Latha Ramalingam, Syracuse; Dr. Alena Savonenko

    c. Species: APPswePS1dE9 amyloidogenic transgenic mouse model of Alzheimer’s disease.

  3. What aspects cause individuals with minoritized identities to persist or desist in STEM?

    a. Funding: NSF

    b. Collaborators: Dr. Elizabeth Sharp, TTU; Dr. Jaclyn Canas-Carrell, TTU; Dr. Dana Weiser, TTU; Dr. Amelia Talley, TTU

    c. Framework: Conference grant to run the #WhyNotMeSTEM conference in Lubbock, TX

Starter Projects

These are projects that have been started and are in various stages of completeness, but each needs someone to take lead so we can get the data and manuscript across the finish line. These would be great projects for a first chapter, for idea building, and/or to get some hands-on experience immediately.

  1. Meta-analysis of HPA axis response to predator cues (see Harris and Carr, 2016; vertebrates)
  2. Human hormonal and behavioral response to predator cues (humans)
  3. Role of cort and testosterone in post-stressor risk-taking behavior (humans)
  4. Variation in 2D:4D ratio but not sex predicts behavioral response to uncertainty (humans)
  5. Test of the dual hormone hypothesis in two data sets (drinking behavior and risk taking in the ultimatum game; humans)
  6. Repeatability of baseline salivary corticosterone in children with Autism Spectrum Disorder (humans)
  7. Relationship among GHLOS, COMT, FAAH, BMI and cognitive function (humans)
  8. Do glucocorticoids inhibit parental behavior? Theoretical and empirical perspectives (review)
  9. Relationship among corticosterone, ghrelin, affective behavior, and amyloid beta in aged male and female APPswePS1dE9 mice
  10. Replication of Harris studies on FAAH, CRFR1, FKBP5 SNPs using a different human aging database.

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