The Mathematical Biology Seminar presents Dr. William Holmes, Professor of Biological Sciences, on “Computational Models of Bouton Afferents in Turtle Utricle: Role of Afferent-Hair Cell Connectivity in Determining Spike Train Regularity” on Tuesday, March 28, from 3:05 to 4 p.m. in Morton 226.
Summary: Vestibular bouton afferent terminals in turtle utricle can be categorized into four types depending on their location and terminal arbor structure: lateral extrastriolar (LES), striolar, juxtastriolar, and medial extrastriolar (MES). To understand how differences in terminal morphology and the resulting hair cell inputs might affect afferent response properties, we modeled representative afferents from each region. The models suggest that all four bouton afferent types are electrotonically compact but that EPSPs are two-to-four-fold larger in MES afferents than in other afferents, making MES afferents more responsive to low input levels. The models also predict that MES and LES terminal structures permit higher spontaneous firing rates than those in striola and juxtastriola. We find that differences in spike train regularity among these afferents are not a consequence of differences in peripheral terminal structure, per se, but depend on the proportion of multiple contacts between afferents and individual hair cells. This prediction has implications for spike train regularity in dimorphic and calyx afferents.
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