Sensory Systems—Audition, Vestibular Sensation and the chemical Senses

Audition

1. Peripheral Auditory Mechanisms
   1. Overview：
   2. The nature of the sound:注：The amplitude: The intensity of the sound. The pitch(两峰间距离)：The frequency注：声音在特定的方向传来时，两只耳朵的接收声音的频率发送相变
   3. Anatomy of the ear:注：Incus和malleus把能量放大了200倍。注：1.Cochlea:The biochemical fuction is to decompose complex sounds into their component frequncy, the neural function of it is to tansduce mechanical energy into neural signals and the communicated through the auditory nerve into the brain stem.注：What explains the tonotopy that is present in the auditory division of CN VIII?——The location of where the peripheral process receives contact from hair cells along the basilar membrane.注：The firing of action potentials in second-­order sensory neurons can be either up-­ or down-­regulated, depending on the direction in which the bundle of cilia (of the afferent hair cell) is bent.
   4. Sensory transduction:
   5. Sensory coding:
2. Central Auditory Processing
   1. Auditory pathways:注：Which auditory structure first displays pronounced selectivity for specific combinations of sound frequencies in the auditory pathway?——medial geniculate complex注：Primary auditory cortex位于superior temporal gyrus,Buried deep in the lateral fissure; superior olive 帮助我们辨别声音的位置。
   2. The superior olive complex:
      1. The medial superior olive:It encodes the localization of sound in space based on inter oral timing differences注：Which of the following most depends upon the utilization of bilateral auditory information?——sound localization
      2. The lateral superior olive:it encodes information about the location of the sound source based on inter oral intensity differences
   3. The Auditory cortex: PAC(A series tansverse gyrus are called Heschl’s Gyri.)、SAC（it includes what we call Wernicke’s area） 注：韦尼克区（理解话语）—位于Posterior aspect of SAC(右撇子位于左脑区，左撇子一般位于右脑区)，对应另一个半球的区域可understanding the emotional content of speech

Vestibular sensation:

1. Overview of the Vestibular function:
2. Head motion:
3. The anatomy of vestibular labyrinth:
4. Sensory tansduction:注：Saccular对Y（pitch）敏感；Utricular对X敏感（平行移动）注：hair cells在红色的bulb里（ampulla）
   1. otolith organs(this would be the macula of the utricle)注：一半de，一半Hy
5. Semicircular canals:注：1. The superior canal in one side of the head is actually operating in the plane of the inferior canal in the opposite side of the head.
   1. 问：When looking up into the night sky (while standing), which of the following events happened deep in the vestibular labyrinth?——The posterior semicircular canals on both sides of your head were phasically activated during the backward tilt of your head；About half of the hair cells in the sacculus on both sides of your head were depolarized while you maintained your head in a backward tilt.
   2. When riding a “merry-­‐go-­‐round” (that rotates in the counterclockwise direction), which of the following events happened deep in the vestibular labyrinth?——The left horizontal semicircular canal was activated.
6. Central Vestibular Processing
   1. Vestibulo-ocular reflex：
   2. Vestibular nystagmus（前庭性眼球震颤-点头）
   3. Posture:the medial spinal chord pathways are concerned with posture, the lateral spinal cord pathways are concerned with what we do with our hands and with our feet.注：MVT（mainly a connection to the cervical spinal cord）与头和脖子的移动有关；LVT（runs the length of the cord)与maintaining the extensor tone of the anti-gravity muscles of the lower extremity有关（阻止我们从一个方向移动到另一个方向）
   4. Higher vestibular processing:
   5. 问：Stare straight ahead at some frontal fixation target. Now turn your head to the right without breaking fixation. What just happened?—The motor neurons in your right oculomotor nucleus that innervate the right medial rectus muscle just increased their firing rate.

Chemical Senses

1. Overview:
2. Olfraction(嗅觉)：
   1. Anatomical overview:注：OT(dorsal and a bit anterior to the level of the optic chiasm)、PC（where the temporal lobe joins the frontal lobe）
   2. Sensory transduction:
   3. Receptors:注：Glomerulus是OE和brain的第一个突触连接
   4. 问：Which of the following statements concerning the encoding of olfactory signals is most accurate?——Central olfactory structures operate using a “temporal code”, since nearly synchronous oscillations in neural activity are broadly distributed when particular odorants are presented.
3. Gustation:
   1. Anatomy:
   2. System:
   3. Sensory transduction:
   4. 问：Which of the following statements concerning the encoding of gustatory signals is most accurate?——Subcortical gustatory processing appears to implement a “labeled-­‐line code” with the neural responses of sensory cells reflecting the molecular properties of the gustatory receptors that drive the response.
4. Trigeminal Chemoreception
   1. anatomy:(TG:nerve5)
   2.  transient receptor potential channels:
   3. Nerve:
   4. 问：If you choose to eat hot and spicy food (as I sometimes do), why does your mouth burn and your scalp sweat (among other visceral sensory and motor reactions)?——1. Capsaicin and related compounds in spicy food activate transient receptor potential (TRP) channels on taste cells in taste buds. 2. Capsaicin and related compounds in spicy food activate transient receptor potential (TRP) channels on free nerve endings of polymodal C nociceptive fibers in oral mucosa. 3. Signals pertaining to the activation of TRP channels are integrated in the nucleus of the solitary tract in the dorsal tegmentum of the caudal pons and upper medulla. 4. Signals pertaining to the activation of TRP channels are integrated in the spinal trigeminal nucleus in the lateral tegmentum of the caudal pons and medulla. 5. Central processing of signals derived from TRP channel activation are distributed to integrative centers in the hypothalamus and brainstem where visceral motor commands are distributed to sweat-­‐promoting preganglionic (sympathetic) neurons. 6. Central processing of signals derived from TRP channel activation are distributed to higher brain centers where sensations are elaborated in cortical networks.