Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells
Sound intensity is encoded by auditory neuron subgroups that differ in thresholds and spontaneous rates. Whether variations in neuronal biophysics contributes to this functional diversity is unknown. Because intensity thresholds correlate with synaptic position on sensory hair cells, we combined pat...
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2020-07-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/55378 |
| _version_ | 1818024094368530432 |
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| author | Alexander L Markowitz Radha Kalluri |
| author_facet | Alexander L Markowitz Radha Kalluri |
| author_sort | Alexander L Markowitz |
| collection | DOAJ |
| description | Sound intensity is encoded by auditory neuron subgroups that differ in thresholds and spontaneous rates. Whether variations in neuronal biophysics contributes to this functional diversity is unknown. Because intensity thresholds correlate with synaptic position on sensory hair cells, we combined patch clamping with fiber labeling in semi-intact cochlear preparations in neonatal rats from both sexes. The biophysical properties of auditory neurons vary in a striking spatial gradient with synaptic position. Neurons with high thresholds to injected currents contact hair cells at synaptic positions where neurons with high thresholds to sound-intensity are found in vivo. Alignment between in vitro and in vivo thresholds suggests that biophysical variability contributes to intensity coding. Biophysical gradients were evident at all ages examined, indicating that cell diversity emerges in early post-natal development and persists even after continued maturation. This stability enabled a remarkably successful model for predicting synaptic position based solely on biophysical properties. |
| first_indexed | 2024-12-10T03:54:45Z |
| format | Article |
| id | doaj.art-a67cb4f8b8c2429f8726f0b83642d8e9 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-12-10T03:54:45Z |
| publishDate | 2020-07-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-a67cb4f8b8c2429f8726f0b83642d8e92022-12-22T02:03:09ZengeLife Sciences Publications LtdeLife2050-084X2020-07-01910.7554/eLife.55378Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cellsAlexander L Markowitz0Radha Kalluri1https://orcid.org/0000-0002-0360-8965Neuroscience Graduate Program, University of Southern California, Los Angeles, United States; Department of Otolaryngology, Keck School of Medicine, University of Southern California, Los Angeles, United StatesNeuroscience Graduate Program, University of Southern California, Los Angeles, United States; Department of Otolaryngology, Keck School of Medicine, University of Southern California, Los Angeles, United States; Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, United StatesSound intensity is encoded by auditory neuron subgroups that differ in thresholds and spontaneous rates. Whether variations in neuronal biophysics contributes to this functional diversity is unknown. Because intensity thresholds correlate with synaptic position on sensory hair cells, we combined patch clamping with fiber labeling in semi-intact cochlear preparations in neonatal rats from both sexes. The biophysical properties of auditory neurons vary in a striking spatial gradient with synaptic position. Neurons with high thresholds to injected currents contact hair cells at synaptic positions where neurons with high thresholds to sound-intensity are found in vivo. Alignment between in vitro and in vivo thresholds suggests that biophysical variability contributes to intensity coding. Biophysical gradients were evident at all ages examined, indicating that cell diversity emerges in early post-natal development and persists even after continued maturation. This stability enabled a remarkably successful model for predicting synaptic position based solely on biophysical properties.https://elifesciences.org/articles/55378spiral-ganglion neuronspatch-clamp methodologydevelopmental gradientsauditory nerveintensity codingbiophysics |
| spellingShingle | Alexander L Markowitz Radha Kalluri Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells eLife spiral-ganglion neurons patch-clamp methodology developmental gradients auditory nerve intensity coding biophysics |
| title | Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| title_full | Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| title_fullStr | Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| title_full_unstemmed | Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| title_short | Gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| title_sort | gradients in the biophysical properties of neonatal auditory neurons align with synaptic contact position and the intensity coding map of inner hair cells |
| topic | spiral-ganglion neurons patch-clamp methodology developmental gradients auditory nerve intensity coding biophysics |
| url | https://elifesciences.org/articles/55378 |
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