Jessica Kendall-Bar Rose Hills
Electrophysiological Recordings of Sleep in the Fur Seal
Marine mammals, after centuries of convergent evolution, have evolved striking cognitive similarities to humans. However, due to the logistical challenges inherent in neurobiological studies with these creatures, our knowledge of the chemicals involved in fundamental behaviors remains limited. My study will examine the concentrations of glutamate, a major neurotransmitter, in concurrence with electrophysiological data (using surgically implanted EEG electrodes) across the varied sleep types exhibited by the northern fur seal. These sleep types include the bilateral slow wave sleep which is exhibited by humans (sleeping in both hemispheres) and the unihemispheric slow wave sleep which is exhibited by cetaceans (sleeping in one hemisphere at a time). The study will also examine the use of eye state and metabolism as alternative indicators of sleep stage in each hemisphere, which would not require the surgical implantation of electrodes (as in the electrophysiological study of sleep stage) and thus could lead to developing a less invasive method for obtaining sleep staging information.
By examining the neurochemistry involved in sleep, a behavior that may likely be critical for survival, this study can provide insight on the possible impacts of both natural and anthropogenic toxins, as well as anthropogenic activity, on sleep in this species. The analysis and quantification of sleep in the fur seal, an animal whose sleep exhibits notable similarities to both cetaceans and humans, can also elucidate neural pathways and aid studies of sleep pathology in each of these cognitively advanced groups.