 | Francisco Velazquez University of Puerto Rico, Aguadilla BiologyMentor(s)Felicia L. Smith Robin L. Davis, Ph.D. Department of Cell Biology and Neuroscience Rutgers University |
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| Branching patterns differ between high and low frequency spiral ganglion neurons | ||
| An extensively examined morphological feature in the auditory system is the branching patterns of the central projections that extend to the Schwann-glial border and bifurcate depending on characteristic frequency (CF). Low CF fibers extend only a short distance and bifurcate at a wide angle in order to innervate their cochlear nucleus targets, while high CF fibers extend for greater distances and bifurcate at a narrower angle. The aim of our project is to measure the axon length and angle of bifurcation elaborated by spiral ganglion neurons in vitro to determine the regulatory elements that control CF-specific morphological characteristics. We used a specialized culture preparation of paired hair cell micro-isolates isolated from different cochlear regions to analyze CF-specific branching patterns. Our preliminary data shows that the hair cell micro-isolates are important in regulating the length of the process. For example, when apical hair cell micro-isolates are paired with apical neurons, the measured length of the process is (631 ± 114 υm, n=5) compared to the basal hair cell micro-isolates paired with basal neurons (314 ± 45 υm, n=6; p<0.05). This indicates that the peripheral receptor cells have a powerful impact on axonal length, even without the presence of the central target cells. Future experiments are designed to examine branching angle as well as to determine the specific factors that affect CF-specific spiral ganglion neuron morphology. Supported by NIH NIDCD R01 DC-01856. |