音の局所化のためのニューロンの集団コード
D C Fitzpatrick1, R Batra, T R Stanford
1Department of Anatomy, University of Connecticut Health Center, Farmington 06030-3405, USA. dcf@neuron.uchc.edu
Nature
|August 28, 1997
まとめ
聴覚神経は,情報が脳を通るにつれて,音の位置のシグナルへの調整を鋭くする. この改善されたニューラルチューニングは,音のローカライゼーションのための集団コードの効率を高めます.
科学分野:
- 神経科学は神経科学である.
- 監査システム 監査システム
- 計算神経科学とは
背景:
- 音の局所化におけるリスナーの精度は,単一のニューロンの空間的感受性を上回ります.
- 聴覚ニューロンの広範囲の空間調整は,音の局所化のための集団コードを示唆しています.
- 音間時間差 (ITD) は,低周波音の局所化の主要なシグナルです.
研究 の 目的:
- 聴覚情報が脳に上昇するにつれて,ITDへのニューラルチューニングがどのように変化するかを調査する.
- ニューラル・チューニングの鋭化が,音の局所化のための集団コードの効率に影響を与えるかどうかを判断する.
主な方法:
- 聴覚系の異なる段階における低周波音 (<2kHz) に対する神経応答の分析.
- ニューロンのチューニングの鋭さから音間時間差 (ITDs) の定量化.
- 観察されたニューラルチューニング特性に基づいて,集団コード効率のモデリング.
主要な成果:
- ITDに対するニューロンの調整は,聴覚系のより高いレベルでは,かなり鋭くなります.
- より鋭いニューラルチューニングにより,音の局所化のための集団コードの効率が向上します.
- 鋭いチューニングで特定のレベルの局所精度を達成するために必要なニューロンは少なくなります.
結論:
- 神経処理は,音の局所化シグナル,特にITDの表現を鋭くする.
- 強化されたニューラルチューニングは,聴覚系における集団コーディングの効率を向上させます.
- このメカニズムは,脳が広範な神経調節にもかかわらず,正確な音の局所化をどのように達成するかを説明します.
関連する概念動画
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.
01:22Hair 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.
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
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...
01:21Perceiving 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...