Related Experiment Video
Updated: May 23, 2026
12:07
Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog (Rana catesbeiana)
Published on: March 17, 2017
Coupling and elastic loading affect the active response by the inner ear hair cell bundles
Clark Elliott Strimbu1, Lea Fredrickson-Hemsing, Dolores Bozovic
1Department of Physics & Astronomy, University of California Los Angeles, Los Angeles, California, United States of America.
Plos One
|April 6, 2012
Summary
Active hair bundle motility amplifies sound and balance detection. Mechanical loading and coupling reduce frequency selectivity, but synchronous active hair bundle movement can displace overlying structures.
Area of Science:
- Auditory neuroscience
- Mechanobiology
- Sensory physiology
Background:
- Active hair bundle motility is crucial for amplification in auditory and vestibular systems.
- Understanding its behavior under natural loading conditions is essential.
Purpose of the Study:
- To investigate the effects of elastic mechanical loading on hair bundle motility.
- To explore the influence of the otolithic membrane on hair bundle dynamics.
- To identify signatures of active processes under natural coupling.
Main Methods:
- Utilized semi-intact bullfrog sacculus preparations.
- Applied elastic mechanical loads (glass fibers) to stereocilia.
- Studied both freely oscillating and natively coupled hair bundles.
- Applied transient mechanical stimuli to the otolithic membrane.
Main Results:
- Hair bundles showed phase-locked responses (Arnold's Tongue), with frequency selectivity decreasing at higher amplitudes and load stiffness.
- Increasing load stiffness broadened the phase-locked response, with optimal broadening near impedance matching.
- Natural loading by the otolithic membrane reduced frequency selectivity.
- Transient stimuli evoked active, opposite-direction bundle movements, with the otolithic membrane moving in phase.
Conclusions:
- Active hair bundle motility's frequency selectivity is modulated by mechanical loading and coupling.
- Synchronous active motility in coupled hair bundles can displace significant overlying structures.
- This active motility plays a key role in sensory transduction and amplification in vertebrates.
More Related Videos
Related Concept Videos
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.
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.
01:15Equilibrium and Balance
The inner ear assumes dual functionalities of auditory perception and equilibrium maintenance. The vestibule is the organ responsible for balance. This organ contains mechanoreceptors, specifically hair cells, endowed with stereocilia, which aid in deciphering information regarding the position and motion of our heads. Two intrinsic components, the utricle and saccule, help perceive head position, while the semicircular canals track head movement. Neurological messages initiated in the...
01:15Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
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...
01:29The Vestibular System
The vestibular system is a set of inner ear structures that provide a sense of balance and spatial orientation. This system is comprised of structures within the labyrinth of the inner ear, including the cochlea and two otolith organs—the utricle and saccule. The labyrinth also contains three semicircular canals—superior, posterior, and horizontal—that are oriented on different planes.