Research
1. Environmental Regulation of Sickness Behavior
At some point, we have all displayed the signs and symptoms of infection, but what adaptive purposes do they serve?
Most organisms deal with infection in a number of clever ways. Besides cellular responses, many animal hosts will undergo a suite of behavioral changes, collectively known as sickness behavior. Such alterations include fever, anorexia (reduced food intake), and reduced social interactions.
My laboratory investigates the life-history costs and benefits of the sickness response in wild vertebrates. We attempt to understand the proximate and ultimate causes that lead to variation of sickness behavior using songbirds as a model species.
Birds can get sick too!Gambel's White-crowned Sparrow (Zonotrichia leucophrys gambelii)Photo credit: Noah Ashley
C57/BL6j mouse: Photo credit: Jackson labs
2. Immune-Sleep Interactions
Sleep is an integral part of our life cycle, but its function is still somewhat of a mystery. What purposes does it serve? One hypothesis is that daily sleep is necessary to maintain immunological performance.
The immune system and sleep interact in a bidirectional fashion. For example, during infection or exposure to immunogens, such as endotoxin, pro-inflammatory cytokines are released and increase the duration of slow-wave (non-rapid eye movement) sleep. Conversely, a lack of sleep can affect immunological performance that can lead to chronic conditions, such as cardiovascular disease. This is because sleep loss leads to a pro-inflammatory state that can have pronounced effects upon homeostatic mechanisms.
My lab is currently investigating these sleep interactions in mammals and birds. The first project investigates the hormonal and vascular mechanisms that affect inflammatory responses to sleep loss in C57BL/6j mice. This project is currently funded by the Kentucky Biomedical Research Infrastructure Network (KBRIN).
The second research project aims to understand how birds respond to sleep loss. Many migratory species will undergo sustained sleep loss during migration. Are there physiological costs of extended wakefulness in birds? My lab is currently assessing the immunological responses of Zebra Finch (Taeniopygia guttata) to acute sleep loss. Currently, we are developing assays to assess pro- and anti-inflammatory gene expression using RTPCR following experimental sleep loss.
3. Sleep Physiology of Arctic-Breeding Songbirds
Organisms inhabiting the polar regions are exposed to extreme environmental conditions in photoperiod (the duration of light within a 24 h period) throughout the year. Around the summer and winter solstices, animals that reside in Antarctica or north of the Arctic Circle (>66°33’) experience weeks to months of either continuous daylight or darkness, respectively. The basic questions that my lab raises are (1) when and how do these animals sleep, and (2), if they forego sleep, are their proximate and ultimate costs?
Lapland longspurs (Calcarius lapponicus), arctic-breeding songbirds that migrate to northern Alaska, only sleep 4-5 hours/day on their breeding grounds. The goal of this research is to investigate sleep-wake cycles in free-living birds using minaturized telemetric devices.
We are also curious how arctic-breeding birds respond to sleep loss. Are they more resilient to physiological, immunological, and behavioral costs of sleep loss than temperate-breeding birds?
Research will occur from May through July in Barrow, Alaska (71 deg. N latitude).
Male (A) and female (B) Lapland longspurs. Both sexes are less
active during the early morning hours than the remainder of polar day in Barrow, Alaska (C). Photo credit- Noah Ashley
