Alexis Mingos

Date of Award

2023

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Leininger, Elizabeth

Area of Concentration

Biopsychology

Abstract

Marine mammals returned to the water through several temporally separated lineages, each species adapting somatosensory mechanisms that allow them to locate and consume food. The species in this study have adapted to underwater environments through different modalities. Manatees, harbor seals, and sea otters all utilize mystacial vibrissae, while manatees also possess lightly scattered thin vibrissae over the entire body, and sea otters employ their sensitive paws for active touch. These sensory differences provide an interesting opportunity to compare and examine the neuroanatomy of mechanoreception in differentially adapted marine species. The brain reflects these adaptations, creating “pathways” formed by neuronal connectivity, with the ventral posterolateral nucleus (VPL) and ventral posteromedial nucleus (VPM) in the thalamus receiving mechanosensory information from the body. Diffusion tensor imaging (DTI) was used to “mask” and visualize the tracts projecting from the VPL and VPM and calculate the strength of the connectivity between these thalamic nuclei and the brainstem. Results indicated significantly stronger connectivity in the sea otter brain compared to the manatee and harbor seal brains. This study examined the connections to the somatosensory thalamic nuclei in three different marine mammal species, assessing the strength of connections to the brain stem, and examining the destinations of cortical projections. This work serves to further the understanding of marine mammal neuroanatomy as a result of their mechanosensory adaptations.

Download

Share

COinS