Browsing by Author "Department of Otolaryngology Head and Neck Surgery, IU School of Medicine"

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    Contribution of Hearing Aids to Music Perception by Cochlear Implant Users
    (Taylor and Francis, 2015) Peterson, Nathaniel; Bergeson, Tonya R.; Department of Otolaryngology Head and Neck Surgery, IU School of Medicine
    Objectives Modern cochlear implant (CI) encoding strategies represent the temporal envelope of sounds well but provide limited spectral information. This deficit in spectral information has been implicated as a contributing factor to difficulty with speech perception in noisy conditions, discriminating between talkers and melody recognition. One way to supplement spectral information for CI users is by fitting a hearing aid (HA) to the non-implanted ear. Methods In this study 14 postlingually deaf adults (half with a unilateral CI and the other half with a CI and an HA (CI + HA)) were tested on measures of music perception and familiar melody recognition. Results CI + HA listeners performed significantly better than CI-only listeners on all pitch-based music perception tasks. The CI + HA group did not perform significantly better than the CI-only group in the two tasks that relied on duration cues. Recognition of familiar melodies was significantly enhanced for the group wearing an HA in addition to their CI. This advantage in melody recognition was increased when melodic sequences were presented with the addition of harmony. Conclusion These results show that, for CI recipients with aidable hearing in the non-implanted ear, using a HA in addition to their implant improves perception of musical pitch and recognition of real-world melodies.
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    Tlx3 promotes glutamatergic neuronal subtype specification through direct interactions with the chromatin modifier CBP
    (Public Library of Science, 2015) Shimomura, Atsushi; Patel, Dharmeshkumar; Wilson, Sarah M.; Koehler, Karl R.; Khanna, Rajesh; Hashino, Eri; Department of Otolaryngology Head and Neck Surgery, IU School of Medicine
    Nervous system development relies on the generation of precise numbers of excitatory and inhibitory neurons. The homeodomain transcription factor, T-cell leukemia 3 (Tlx3), functions as the master neuronal fate regulator by instructively promoting the specification of glutamatergic excitatory neurons and suppressing the specification of gamma-aminobutyric acid (GABAergic) neurons. However, how Tlx3 promotes glutamatergic neuronal subtype specification is poorly understood. In this study, we found that Tlx3 directly interacts with the epigenetic co-activator cyclic adenosine monophosphate (cAMP)-response element-binding protein (CREB)-binding protein (CBP) and that the Tlx3 homeodomain is essential for this interaction. The interaction between Tlx3 and CBP was enhanced by the three amino acid loop extension (TALE)-class homeodomain transcription factor, pre-B-cell leukemia transcription factor 3 (Pbx3). Using mouse embryonic stem (ES) cells stably expressing Tlx3, we found that the interaction between Tlx3 and CBP became detectable only after these Tlx3-expressing ES cells were committed to a neural lineage, which coincided with increased Pbx3 expression during neural differentiation from ES cells. Forced expression of mutated Tlx3 lacking the homeodomain in ES cells undergoing neural differentiation resulted in significantly reduced expression of glutamatergic neuronal subtype markers, but had little effect on the expression on pan neural markers. Collectively, our results strongly suggest that functional interplay between Tlx3 and CBP plays a critical role in neuronal subtype specification, providing novel insights into the epigenetic regulatory mechanism that modulates the transcriptional efficacy of a selective set of neuronal subtype-specific genes during differentiation.