揭開聽覺奧秘的 A. James Hudspeth 逝世，享年79歲（1/2）

Recently the New York times picked up the following:

A. James Hudspeth, Who Unlocked Mysteries Behind Hearing, Dies at 79 (1/2)

He was pivotal in discovering how sound waves are converted into signals that the brain can perceive as a whisper, a symphony or a thunderclap.

By Jeré Longman

Sept. 5, 2025

Dr. A. James Hudspeth, a neuroscientist at the Rockefeller University in Manhattan who was pivotal in discovering how sound waves are converted in the inner ear to electrical signals that the brain can perceive as a whisper, a symphony or a thunderclap, died on Aug. 16 at his home in Manhattan. He was 79.

His wife, Dr. Ann Maurine Packard, said the cause was glioblastoma, a brain cancer.

Scientists have long understood how sound waves enter the ear canal and cause the eardrum to vibrate. They have also understood how the vibrations travel through the three small bones of the middle ear, then to the cochlea in the inner ear, a tiny organ about the size of a chickpea that is filled with fluid and is shaped like a snail’s shell.

And they have long known that microscopic receptor cells in the cochlea play a role in the process of hearing. But by the time Dr. Hudspeth began his research in the 1970s, it was still unclear how these cells — known as hair cells (the name derives from tufts of cylindrical, hairlike rods known as stereocilia) — transformed the mechanical vibrations of sound waves into nerve impulses that the brain could interpret as, say, a child crying or a dog barking.

Dr. Hudspeth “provided the major framework” for this understanding, the committee that awarded him and two other scientists (Robert Fettiplace and Christine Petit) the Kavli Prize in Neuroscience for their pioneering work on the processes of hearing wrote in its citation in 2018.

Each cochlea contains about 16,000 hair cells. Atop each cell, 20 to 300 of these rods are gathered in a bundle — the shortest to the tallest — in rows that resemble a staircase or a pipe organ. Hair cells line the cochlea, with each tuned to a narrow frequency range that collectively decodes the broad spectrum of tones in every sound.

As sound waves enter the cochlea, the stereocilia rods begin to slide next to one another. Dr. Hudspeth theorized that this motion toward the tallest rods created tension on elastic tethers that pulled open tiny pores — essentially trap doors — on the tips of the stereocilia.

His hunch was supported by another scientist, James Pickles, who discovered that each rod is attached to neighboring rods by an elastic protein filament, a kind of microscopic rubber band or spring.

Dr. Hudspeth revealed that when the trap doors open, positively charged ions of potassium and calcium flood into the cells, creating an electrical signal that is carried by the auditory nerve to the brain.

The opening and closing of the trap doors, Dr. Hudspeth found, happens in microseconds, a speed 1,000 times as fast as that of our other senses. The stereocilia, he said, can create a signal that the brain detects by moving only the width of a water molecule.

He showed that hearing depends not only on speed but also on a built-in amplifier system, which can boost a sound signal by about 1,000-fold and sharpens frequency tuning, making it easier to tell voices apart and understand nuances in speech.

Dr. Hudspeth “was the one who really figured out how hair cells worked,” David Corey, a neuroscientist at Harvard and one of his former graduate students, said in an interview.

Albert James Hudspeth was born on Nov. 9, 1945, in Houston. His father, Chalmers Hudspeth, was a lawyer. His mother, Demaris (De Lange) Hudspeth ran the household.

From an early age, Jim, as he was known to his colleagues, was drawn to the orderliness of nature. He and his brother, Tom, amassed a menagerie at home of 200 animals, including box turtles, toads, raccoons, opossums and armadillos.

He attended Harvard, where he received a bachelor’s degree in biomechanical sciences in 1967, a master’s degree in neuroscience in 1969, a Ph.D. in neuroscience in 1973 and a Doctor of Medicine degree in 1974. He joined the Rockefeller University’s faculty in 1995 and was a member of the National Academy of Sciences.

(to be continued)

Translation

揭開聽覺奧秘的 A. James Hudspeth 逝世，享年79歲（1/2）

他在發現聲波如何轉換成大腦可以感知為耳語、交響樂或雷鳴的信號方面發揮了關鍵作用

曼哈頓洛克菲勒大學的神經科學家 A. James Hudspeth 博士於8月16日在曼哈頓的家中去世，享年79歲。他在發現聲波如何在內耳轉換成大腦可以感知為耳語、交響樂或雷鳴的電訊號方面發揮了關鍵作用。

他的妻子 Ann Maurine Packard 博士表示，他的死因是腦癌 - 膠質母細胞瘤。

科學家早已了解聲波如何進入耳道並引起耳膜振動。他們也了解振動是如何通過中耳的三塊小骨頭傳遞到內耳的耳蝸的。耳蝸是一個鷹嘴豆大小的微小器官，充滿液體，形狀像蝸牛殼。

科學家們早就知道耳蝸中的微小受體細胞在聽覺過程中發揮作用。但到了1970年代 Hudspeth 博士開始他的研究時，人們仍然不理解清楚這些被稱為毛細胞（毛細胞的名稱源於一簇圓柱形、毛狀的桿狀細胞，稱為立體纖毛）的細胞是如何將聲波的機械振動轉化為大腦可以解讀為例如是孩子哭聲或狗吠聲的神經脈衝。

2018年，Kavli神經科學獎授予了 Hudspeth 博士和另外兩位科學家（Robert Fettiplace 和Christine Petit）。委員會在頒獎詞中寫道，Hudspeth 博士「為這一理解提供了重要的框架」而表彰他們在聽覺過程方面的開創性工作。

每個耳蝸包含約16,000個毛細胞。每個毛細胞頂部，有20到300個桿形細胞聚集成束－從最短到最長－排列成行，形狀像樓梯或管風琴。毛細胞排列在耳蝸內，每個毛細胞都調諧到一個較窄的頻率範圍，共同解碼每個聲音中的廣泛音調。

當聲波進入耳蝸時，立體纖毛桿開始彼此並排滑動。Hudspeth博士推測，這種向最高桿形細胞的移動會在彈性繫繩上產生張力，從而拉開立體纖毛尖端的微小孔隙 - 它本質上是個活門。

另一位科學家 James Pickles 也支持了他的推測。Pickles 發現，每根桿狀細胞都透過一根彈性蛋白絲（一種微型橡皮筋或彈簧）與相鄰的桿狀細胞連接。

Hudspeth 博士透露，當活門打開時，帶正電的鉀離子和鈣離子會湧入細胞，產生電訊號，並透過聽覺神經傳遞到大腦。

Hudspeth 博士發現，活門的開啟和關閉以微秒為單位，速度是我們其他感官的1,000倍。他說，立體纖毛只需移動一個水分子的寬度就能產生大腦所能感知的訊號。

他指出，聽覺不僅取決於速度，還取決於一個內建的擴大機系統，可以將聲音訊號增強約1,000倍，並銳化頻率調較，從而更容易區分聲音並理解言語中的細微差別。

哈佛大學神經學家、Hudspeth 博士以前的研究生之一 David Corey 在一次採訪中說道, Hudspeth博士 “是真正弄清毛細胞工作原理的人” 。

Albert James Hudspeth 於1945年11月9日出生於休士頓。他的父親 Chalmers Hudspeth 是一名律師。母親 Demaris (De Lange) Hudspeth 則負責日常家庭事務。

被同事們都這稱呼為Jim的他從小就被大自然的秩序所吸引。他和弟弟Tom在家裡養了200隻動物，包括箱龜、蟾蜍、浣熊、負鼠和犰狳。

他畢業於哈佛大學，1967年獲得生物力學學士學位，1969年獲得神經科學碩士學位，1979年獲得博士學位。 1973年獲得神經科學博士學位，1974年獲得醫學博士學位。 1995年加入洛克斐勒大學任教，並曾是美國國家科學院院士。

（待續）