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ANATOMY, PHYSIOLOGY, AND DISORDERS OF THE AUDITORY SYSTEM - PART 6

Tất cả các cấu trúc thần kinh của các con đường thính giác tăng dần có thể tạo ra âm thanh khơi dậy tiềm năng điện có thể được ghi lại bởi một điện cực được đặt vào cấu trúc tương ứng. 2. Tiềm năng hợp chất hành động (CAP) | CHAPTER 7 Evoked Potentials from the Nervous System 1. ABSTRACT 1. All neural structures of the ascending auditory pathways can generate sound evoked electrical potentials that can be recorded by an electrode placed on the respective structure. 2. Compound action potentials CAP recorded directly from the intracranial portion of the auditory nerve in small animals are different from those recorded in humans because the eighth cranial nerve is longer in humans than in small animals 2.5 cm in humans and approximately 0.8 cm in the cat . 3. In humans the latency of the main negative peak of the CAP recorded with a monopolar electrode from the intracranial portion of the human auditory nerve is approximately one millisecond longer than that of the N1 component of the action potential AP recorded from the ear. 4. Evoked potentials recorded with a bipolar electrode from a long nerve such as the human auditory nerve represent propagated neural activity. 5. The responses recorded from the auditory nerve to continuous low frequency sounds is the frequency following response FFR . 6. The response recorded from the surface of a nucleus such as the cochlear nucleus and the inferior colliculus in response to transient sounds has an initial positive-negative deflection which is generated by the termination of the nerve that serves as the input to the nucleus. The slow deflection that follows is generated by dendrites and the fast components riding on the slow wave are somaspikes generated by firings of nerve cells. 7. Far-field evoked potentials are the potentials that can be recorded from locations that lie far from the anatomical location of their generators such as the surface of the scalp. 8. Neural activity in many of the structures of the classical ascending auditory pathways but not all give rise to far-field evoked potentials that can be recorded from electrodes placed on the scalp. 9. Auditory brainstem responses ABR and the middle latency responses MLR are far-field .