Anatomy & Neurobiology Research Opportunities
Lisa Cooper, Ph.D.
Mechanosensitivity in the Bone and Cartilage Cells of Mammals
Within mammals, cells of cartilage and bone are mechanosensitive and respond to loads both within their living matrix as well as when loaded in a petri dish (in vitro). However, little is known of differences in the responsiveness of these cells in animals that live in extreme habitats. To increase our understanding of the variation in bone and cartilage cell sensitivity to loads across mammals, this study aims to establish a fundamental understanding of cell mechanosensitivity in terrestrial (mouse), aerial (bat) and marine (whale) mammals. This study uses species specific-primers and standard PCR techniques to compare dynamics of gene expression in cells harvested from bone and loaded in vitro. We hypothesize that the cells of bats will be either just as mechanosensitive or more mechanosensitive compared to the mouse, but those of the whale will be much less responsive to loads compared to mice and bats. Results will establish a new, foundational dataset. We therefore expect our results will add a critical understanding to the physiology of connective tissues across a taxonomically broad survey of mammals. Students interested in participating in this research should demonstrate fluency in PCR and cell culture.
Alexander Galazyuk, Ph.D.
Neural Mechanisms Underlying Age-Related Hearing Loss
Age-related hearing loss remains one of the most common chronic conditions of aging. It begins from the gradual loss or impairment of the inner and outer hair cells in the cochlea. This loss leads to the development of deficits in the central auditory system which eventually cause difficulties in processing temporally complex sounds such as speech, especially in noisy environments. Typically, individuals experience a notable decline in their hearing abilities after the age of 65, whereas cochlea degradation begins much earlier in life. Within the field, there exists a consensus that central plasticity, often referred to as central gain enhancement, serves as a compensatory mechanism to counterbalance the loss of input from the cochlea to the central auditory system due to aging. The postsynaptic mechanism underlying this compensation is largely unknown. It has been hypothesized that alterations in the balance between excitation and inhibition may play the key role. The goal of this project is to elucidate the postsynaptic mechanisms that contribute to the central gain and to identify pharmacological therapy to improve hearing performance in aged individuals.
Neysa Grider-Potter, Ph.D.
Locomotor Energetics in Sifaka: Contexts and Consequences of Terrestrial Locomotion Using Arboreal Anatomy
Bipedal locomotion is rare among mammals, making it difficult to study the functional morphology and selective pressures associated with its evolution. The human fossil record preserves a gradual accumulation of the human-like traits we associate with upright bipedal walking gaits that are thought to make bipedal locomotion mechanically efficient. Modern human bipedalism is energetically efficient, but terrestrial quadrupedalism and bipedalism in living apes are equivalent to each other in terms of cost and both are more costly than human bipedalism. At present, the energetic costs of bipedal locomotion in other primates are not well-known. Sifakas, a type of lemur who use a bipedal gait when moving terrestrially, present an ideal opportunity to ask what aspects of anatomy and locomotor energetics may have favored the evolution of obligate bipedalism in the hominin lineage but not in other lineages. Sifakas practice bipedal locomotion in the wild but do not have the same anatomical specializations seen in humans. Examining the efficiency and context of sifaka bipedalism will elucidate necessary anatomy and ecologies for obligate bipedalism to evolve. This study explores the comparative energetic costs of sifaka terrestrial bipedal locomotion and arboreal vertical clinging and leaping (VCL). Energy expenditure in captive and wild sifakas (Propithecus verreauxi) engaging in VCL and bipedal locomotion will be measured using doubly labeled water. As the frequency of terrestrial, bipedal locomotion increases, energy expenditure should increase. Lemur habitats are becoming increasingly deforested (potentially mirroring the context of hominin bipedal evolution), and we further expect energy expenditure to be greater in subjects who must locomote terrestrially more frequently. This project has the potential to further our understanding of the evolution of hominin bipedalism, its ecological context, and its anatomical correlates.
Julia Huyck, Ph.D.
Processes Underlying Immature Auditory Perception during Adolescence
Hearing and listening are critical to how adolescents communicate, learn new information, and engage with technology and culture; however, performance on auditory perceptual tasks takes a long time to become mature. Because few studies of auditory perception have centered on typically developing adolescents, little is known about the mechanisms underlying this immaturity. This project will evaluate the extent to which auditory stimulus encoding and various cognitive processes contribute to immature auditory perception during adolescence, using a combination of perceptual testing, neuropsychological and language testing, eye-tracking, and auditory evoked potentials (electrophysiology).
Bradley Winters, Ph.D.
Dendritic Arbor Analysis of Patch-Clamped Lateral Superior Olive Neuron Types
The superior olivary complex (SOC) in the brainstem of mammals integrates information from the two ears enabling sound localization. This ability underlies selective auditory attention and is disrupted by hearing loss and in children with central auditory processing disorder (CAPD). Principal neurons of the lateral superior olive (LSO PNs) are critical for these functions. The classical view of the LSO is a homogeneous block of cells that extracts ongoing interaural level differences (ILDs), however, LSO is increasingly implicated in encoding interaural time differences (ITDs) for broadband transients and amplitude modulations. Cellular properties are fundamental to how neurons extract and encode information. ILD/ITD processing places disparate demands on neuronal properties and there is cellular diversity in the LSO that is not well-understood. It is also critical to understand how different types of information may be organized in higher processing centers of the inferior colliculus (IC).
We found that LSO PNs consist of inhibitory and excitatory cell types with different projection patterns, intrinsic membrane properties, and morphology. We will further probe the functional implications of our preliminary findings on the intrinsic membrane properties of LSO PN types by examining the synaptic drive onto these cells with the goal of finding input-output relationships that support different sound localization coding strategies. Preliminary studies show that inhibitory LSO PNs have lower activation threshold, however, cell-type specific synaptic drive could accentuate or offset these differences. We also found that excitatory LSO PNs have more complicated dendritic arbors suggesting they may integrate more synaptic inputs which could favor ILD coding. Since LSO PN dendrites mainly receive excitatory inputs, this finding suggests the hypothesis that excitatory LSO PNs receive more excitatory inputs than inhibitory LSO PNs. To test this, we will examine the number, strength, balance, short-term dynamics, and channel kinetics of synaptic inputs ex vivo using whole-cell patch-clamp. The recorded neurons will be filled with a marker and the brain slices fixed and mounted so that their dendritic arbors can be analyzed.
Jesse Young, Ph.D.
An Empirical Investigation of Functional Variation in Trabecular Bone Morphology
Bone researchers have long assumed that trabecular bone form might be structurally
optimized to resist the common loading regimes. However, few empirical data exist to directly associate variation in trabecular bone morphology with functional variation in load resistance. In this research project, we will use 3D printing to create physical models that precisely vary aspects of trabecular number, thickness, and spacing. Models will be loaded using a universal material testing machine, allowing us to quantitatively diagnose how variation in trabecular form impacts the capacity for load resistance.
CONTACT
Nona Hose
Phone: 330.325.6499
Email: nhose@neomed.edu
These projects are funded by the Office of Research and Sponsored Programs (ORSP).
Student Research Fellowship Program
