周波数と振幅で調節された音のための一般的な神経コード
1Department of Psychology, University of Florida, Gainesville 32611, USA.
Nature
|April 6, 1995
まとめ
聴覚系は,周波数調節 (FM) と振幅調節 (AM) の音を,脳幹の共有神経コードに変換する. これにより,音の相差に基づいて音の空間的位置を認識することができます.
科学分野:
- 聴覚神経科学とは
- バイオアコースティクス バイオアコースティクス
- センサリー処理 センサリー処理
背景:
- 自然に発生する音は,しばしば振幅調節 (AM) または周波数調節 (FM) を特徴とする.
- AMサウンドの解読は,モジュレーションエンベロープへのニューラルフェーズロックに依存しています.
- FM音の解読のメカニズムは,フラットなFMエンベロープのため,あまり理解されていません.
研究 の 目的:
- 聴覚系が周波数調節 (FM) をどのように解読するかを調査する.
- 聴覚経路におけるFMからAMへのトランスデュークションの可能性を調査する.
- FMとAMの音が共通の神経コードに変換されているかどうかを判断する.
主な方法:
- FMとAMの音の相差が先行または後退している参加者を提示します. 異なる耳に届く音.
- 段階的関係を識別する参加者の能力を評価する.
- 結果となる頭蓋内画像の知覚された空間的位置を分析する.
主要な成果:
- 観測者は,FMとAMの相差をミリ秒以下で正確に検出することができました.
- 単一の頭蓋内画像が認識されました.
- 画像の知覚された空間的位置は,FM信号とAM信号の相差に依存していた.
結論:
- 脳の幹は,FMとAMの両方の音を共通の神経表現に変換します.
- この共通のコードは,聴覚的空間情報の統合を可能にします.
- FMからAMへのトランスデュークションは,聴覚経路の初期に発生し,効率的な音のエンコーディングを可能にします.
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関連する概念動画
Hearing
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.
Hair 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.
The 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.
Perception of Sound Waves
The human ear is not equally sensitive to all frequencies in the audible range. It may perceive sound waves with the same pressure but different frequencies as having different loudness. Moreover, the perception of sound waves depends on the health of an individual's ears, which decays with age. The health of one's ears may also be affected by regular exposure to loud noises.
The pitch of a sound depends on the frequency and the pressure amplitude of the source. Two sounds of the same frequency...
The pitch of a sound depends on the frequency and the pressure amplitude of the source. Two sounds of the same frequency...
Auditory 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...
Perceiving 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...
