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Updated: Jun 22, 2026
08:24
Slicing the Embryonic Chicken Auditory Brainstem to Evaluate Tonotopic Gradients and Microcircuits
Published on: July 12, 2022
Tonotopic reorganization of developing auditory brainstem circuits.
Karl Kandler1, Amanda Clause, Jihyun Noh
1Department of Otolaryngology, University of Pittsburgh School of Medicine, Eye and Ear Institute, Pittsburgh, Pennsylvania, USA. kkarl@pitt.edu
Nature Neuroscience
|May 28, 2009
Summary
Tonotopy, the brain
Area of Science:
- Neuroscience
- Auditory System Research
- Developmental Neurobiology
Background:
- Tonotopy is a core organizational principle in auditory brain circuits.
- It represents sound frequency sensitivity in an orderly manner.
- The precise mechanisms establishing tonotopy remain largely unknown.
Purpose of the Study:
- To investigate the developmental mechanisms underlying the establishment of precise tonotopic maps in auditory brainstem pathways.
- To explore the role of synaptic refinement in tonotopy formation.
Main Methods:
- Analysis of developing auditory brainstem nuclei.
- Examination of subcellular and circuit-level changes during development.
Main Results:
- Auditory brainstem circuits exhibit significant refinement during development.
- This refinement occurs at both subcellular and circuit levels.
- Evidence suggests synaptic reorganization plays a crucial role.
Conclusions:
- Developing auditory brainstem circuits undergo substantial refinement.
- Synaptic reorganization is critical for constructing precise tonotopic maps.
- This challenges previous assumptions about the limited role of plasticity in early tonotopy development.
Related Concept Videos
01:15Auditory Pathway
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
01:31Hearing
When we hear a sound, our nervous system is detecting sound waves—pressure waves of mechanical energy traveling through a medium. The frequency of the wave is perceived as pitch, while the amplitude is perceived as loudness.
01:21Perceiving Loudness, Pitch, and Location
The human brain perceives pitch through two primary mechanisms reflected in place theory and frequency theory. Each mechanism describes how sound waves are interpreted as specific pitches by the brain, offering insights into the intricate processes of auditory perception.
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...
Place theory, or place coding, suggests that different pitches are heard because various sound waves activate specific locations along the cochlea's basilar membrane. The brain determines the pitch of a sound by identifying...
01:16Anatomy of the Ear
Auditory sensation, commonly called hearing, involves the transformation of sonic waves into neural impulses facilitated by the structures of the auditory organ. The prominent, flesh-like structure on the side of the head, called the auricle, directs sound waves towards the auditory canal. The auricle is often mislabeled as the pinna, a term more aligned with mobile structures like a feline's external ear. The auditory canal penetrates the cranium via the external auditory meatus of the...
01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.