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Updated: Aug 9, 2026
In Ovo Electroporation in the Chicken Auditory Brainstem
Published on: June 9, 2017
Emergence of hearing in the chicken embryo
Timothy A Jones1, Sherri M Jones, Kristina C Paggett
1Department of Communication Sciences and Disorders, School of Allied Health Sciences, East Carolina University, Greenville, NC 27858, USA. Jonesti@ecu.edu
Insights
Chicken embryo hearing develops later than previously thought. Cochlear ganglion neurons show sound encoding and frequency selectivity starting around incubation day 15 (E15), with mature responses by E18.
Area of Science:
- Auditory Neuroscience
- Developmental Biology
- Otolaryngology
Background:
- Hearing onset in chicken embryos (Gallus domesticus) is commonly cited as incubation day 12 (E12).
- Limited data exists on cochlear ganglion neuron response properties before incubation day 18 (E18).
Purpose of the Study:
- Determine when primary afferent neurons in chicken embryos begin encoding sounds.
- Identify when frequency selectivity emerges in these neurons.
- Characterize the range of characteristic frequencies (CFs) in late-term embryos.
- Assess the impact of sound transmission from air to the cochlea on embryonic and hatchling responses.
Main Methods:
- Studied cochlear ganglion neurons from chicken embryos (E12-E18) and hatchlings (P13-P15).
- Compared responses to airborne sound versus direct columella footplate stimulation.
- Analyzed the emergence and maturation of sound encoding and frequency selectivity.
Main Results:
- Cochlear ganglion neurons showed profound insensitivity to sound from E12 to E16.
- Sound responses and frequency selectivity appeared around E15.
- Frequency selectivity rapidly matured from E16 to E18, showing a mature CF range (170-4,478 Hz).
- Limited high-frequency sound transmission restricted airborne sound responses in late embryos.
Conclusions:
- Proposed two developmental periods: a prehearing phase (E12-E16) for endogenous signaling and a hearing phase (E16-E19) for sound detection and encoding.
- Hearing onset and functional frequency selectivity in chicken embryos occur later than E12, with significant development between E15 and E18.
Abstract:
It is commonly held that hearing generally begins on incubation day 12 (E12) in the chicken embryo (Gallus domesticus). However, little is known about the response properties of cochlear ganglion neurons for ages younger than E18. We studied ganglion neurons innervating the basilar papilla of embryos (E12-E18) and hatchlings (P13-P15). We asked first, when do primary afferent neurons begin to encode sounds? Second, when do afferents evidence frequency selectivity? Third, what range of characteristic frequencies (CFs) is represented in the late embryo? Finally, how does sound transfer from air to the cochlea affect responses in the embryo and hatchling? Responses to airborne sound were compared with responses to direct columella footplate stimulation of the cochlea. Cochlear ganglion neurons exhibited a profound insensitivity to sound from E12 to E16 (stages 39-42). Responses to sound and frequency selectivity emerged at about E15. Frequency selectivity matured rapidly from E16 to E18 (stages 42 and 44) to reflect a mature range of CFs (170-4,478 Hz) and response sensitivity to footplate stimulation. Limited high-frequency sound transfer from air to the cochlea restricted the response to airborne sound in the late embryo. Two periods of ontogeny are proposed. First is a prehearing period (roughly E12-E16) of endogenous cochlear signaling that provides neurotrophic support and guides normal developmental refinements in central binaural processing pathways followed by a period (roughly E16-E19) wherein the cochlea begins to detect and encode sound.
