Alexys Siagel

Date of Award

2025

Document Type

Thesis

Degree Name

Bachelors

Department

Social Sciences

First Advisor

Cook, Peter

Area of Concentration

Biopsychology

Abstract

Vocal behavior in mammals ranges from stereotyped, reflexive calls to highly flexible, learned vocalizations. While research has traditionally emphasized cortical and basal ganglia circuits in vocal learning, recent work has highlighted the cerebellum’s expanding role in modulating complex, adaptive motor behavior. This study uses diffusion tensor imaging (DTI)-based tractography to investigate cerebellar connectivity from five key regions involved in respiration, swallowing, and vocalization—the nucleus ambiguus, periaqueductal gray, basal ganglia, anterior ventral lateral thalamus, and vocal motor cortex - across four species: harbor seal, elephant seal, California sea lion, and coyote. Results revealed that pinnipeds exhibit broader, denser, and more lateralized cerebellar projections, particularly into lobules VI, Crus I/II, and posterior zones such as lobules VIIIa, IX, and X, compared to the coyote’s more vermis-centered and anterior cerebellar targets. These findings suggest that semi aquatic species may rely on enhanced cerebellar integration to coordinate volitional motor behaviors like vocal production and breath control across shifting environmental contexts. The cerebellum, known for its role in predictive motor control and sensory integration, is likely to support this behavioral flexibility by enabling rapid adjustment of motor output in response to environmental changes. These results reinforce the cerebellum’s contribution not only to movement coordination, but also to higher-order motor behaviors requiring precision, timing, and adaptability.

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