BASIC AND CLINICAL STUDIES OF THE AUDITORY SYSTEM

为了给听力障碍的治疗提供合理的依据， 大波士顿地区的机构已经加入， 多学科小组进行生理机制的研究 在脊椎动物的听觉中起作用。 定义了系统的五个阶段 研究：1.）中耳把声音从外界传到 内耳 测量物理变量，如声压， 听骨运动，耳蜗的声输入阻抗， 选择脊椎动物。 声传播的数学模型 从这些数据和中耳的影响中产生中耳 探索肌肉收缩; 2.）在cochler中， 发生对神经活动的听觉刺激。 的关系 神经纤维对毛细胞形态的反应 神经支配和外周神经支配模式将通过以下方式进行研究： 在蜥蜴的细胞内标记生理上可识别的纤维 耳蜗 毛细胞递质的化学性质将是 研究的帮助下，生物测定敏感的鱼器官提取物丰富 在毛细胞中; 3.）听觉神经向大脑提供输入 从耳朵。 语音信息的编码将通过以下方式来解决： 从麻醉的听神经中的有髓纤维记录 猫 螺旋神经节神经元的记录产生了小的， 将在豚鼠中尝试听觉神经中的无髓鞘纤维; 4.）耳蜗核是大脑中的第一听觉核团。 的 中枢神经系统中无髓纤维的投射和连接 听神经将被跟踪，因为它们在耳蜗核中分叉， 成年猫 无髓鞘神经末梢的大体分布 纤维和母体细胞体的形态将被探索， 免疫学方法;和5.）中枢神经通路提供了 大脑中处理听觉信号的神经回路。 两 将研究反馈机制。 首先是中耳肌 反射途径，将在猫中定义和研究。 二是 耳蜗传出供应，将在手术患者中进行检查 通过测试人类的生理反应和心理物理表现 在橄榄耳蜗束被切断之前和之后 在另一组 研究表明，双耳感知将与人类的诱发电位有关。

In order to develop rational bases for treatment of hearing disorders, four institutions of the greater Boston area have joined in forming a multidisciplinary group to conduct research on the physiological mechanisms that operate in vertebrate hearing. Five stages of the system are defined for study: 1.) The middle-ear which transmits sound from the external to the inner ear. Measurements of physical variables such as sound pressure, ossicular movement, acoustic input impedance to the cochlea are made in selected vertebrates. Mathematical models for sound transmission through the middle ear are generated from these data and effects of the middle-ear muscle contractions are explored; 2.) The cochler where transduction of accoustic stimuli to neural activity occur. The relationship of auditory-nerve fiber responses to the morphology of the hair cells innervated and the peripheral innervation pattern will be studied by intracellularly marking physiologically identified fibers in the lizard cochlea. The chemical nature of the hair-cell transmitter(s) will be studied with the aid of bioassays sensitive to extracts of fish organs rich in hair cells; 3.) The auditory nerve which provides the input to the brain from the ear. The coding of speech information will be addressed by recording from myelinated fibers in the auditory nerve of anesthetized cats. Recordings from spiral ganglion neurons giving rise to the small, unmyelinated fibers in the auditory nerve will be attempted in guinea pigs; 4.) The cochlear nucleus is the first auditory nucleus in the brain. The central projections and connections of the unmyelinated fibers in the auditory nerve will be followed as they ramify in the cochlear nucleus of adult cats. The gross distribution of the endings from the unmyelinated fibers and the morphology of the parent cell bodies will be explored by immunological methods; and 5.) The central neural pathways that provide the neuronal circuitry in the brain for processing auditory signals. Two feedback mechanisms will be studied. The first is the middle-ear-muscle reflex pathway, which will be defined and studied in cats. The second is the cochlear efferent supply, which will be examined in surgical patients by testing physiological responses and psychophysical performance in humans before and after the olivocochlear bundle is cut. In another set of studies, binaural perception will be related to evoked potentials in man.