一項研究報告說，一些靈長類動物比其他哺乳動物能更精細(xì)地分辨出復(fù)雜聲音的頻率,。
聲音在耳蝸中產(chǎn)生振動,，這能帶來聽覺所需的神經(jīng)信號。
耳蝸把聲音分解為成分頻率的能力稱為頻率調(diào)諧,，它對于識別聲音及其位置具有關(guān)鍵作用,。Christopher Shera及其同事測量了獼猴的頻率調(diào)諧。
獼猴是比貓,、豚鼠和毛絲鼠—這些動物的聽覺經(jīng)常得到研究—與人類親緣關(guān)系更近的靈長類動物,。通過釋放另一種聲音，測量耳蝸對聲音響應(yīng)的時間可以間接測量頻率調(diào)諧,。
獼猴的耳蝸聲釋放延遲介于人類和這些常見的實(shí)驗室動物之間,。這組作者還記錄了來自獼猴個體的聽神經(jīng)纖維的響應(yīng)，結(jié)果發(fā)現(xiàn)它們的頻率調(diào)諧比在常見的實(shí)驗室動物身上觀察到的顯著更敏銳,，但是類似于估計的人類最高頻率的頻率調(diào)諧,。
這組作者報告說，精細(xì)地分辨音頻的能力可能是靈長類動物的一個一般屬性,。這組作者提出,，這些發(fā)現(xiàn)可能有助于科研人員開發(fā)聽覺修復(fù)的算法，從而緩解聽力喪失,。（生物谷 Bioon.com）
doi:10.1073/pnas.1105867108
PMC:
PMID:
Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans
Philip X. Joris, Christopher Bergevin,, Radha Kalluri, Myles Mc Laughlin, Pascal Michelet, Marcel van der Heijden, and Christopher A. Shera
Frequency selectivity in the inner ear is fundamental to hearing and is traditionally thought to be similar across mammals. Although direct measurements are not possible in humans, estimates of frequency tuning based on noninvasive recordings of sound evoked from the cochlea (otoacoustic emissions) have suggested substantially sharper tuning in humans but remain controversial. We report measurements of frequency tuning in macaque monkeys, Old-World primates phylogenetically closer to humans than the laboratory animals often taken as models of human hearing (e.g., cats, guinea pigs, chinchillas). We find that measurements of tuning obtained directly from individual auditory-nerve fibers and indirectly using otoacoustic emissions both indicate that at characteristic frequencies above about 500 Hz, peripheral frequency selectivity in macaques is significantly sharper than in these common laboratory animals, matching that inferred for humans above 4–5 kHz. Compared with the macaque, the human otoacoustic estimates thus appear neither prohibitively sharp nor exceptional. Our results validate the use of otoacoustic emissions for noninvasive measurement of cochlear tuning and corroborate the finding of sharp tuning in humans. The results have important implications for understanding the mechanical and neural coding of sound in the human cochlea, and thus for developing strategies to compensate for the degradation of tuning in the hearing-impaired.
