普通生物學 -- 神經系統與應用 Chapter 49 神經系統 Nervous System ( 中樞神經系統 CNS) 柯立偉老師 交通大學生物科技學系 Outline Nervous System 神經系統 (review) Organization of Vertebrate Nervous System Five Different Neurons in Nervous System Glia Cell in the Nervous System Central Nervous System (CNS) Neuroanatomy and Development ( 大腦神經解剖與建置 ) Brain and Spinal Cord Overview ( 大腦, 小腦, 間腦, 腦幹 ) 大腦 間腦 腦幹 小腦 脊隨 國立交通大學生物科技學系柯立偉老師 1
Organization of Vertebrate Nervous System In vertebrates The CNS is composed of the brain and spinal cord The peripheral nervous system (PNS) is composed of nerves and Central nervous Peripheral nervous ganglia. system (CNS) system (PNS) Brain Spinal cord Cranial nerves Ganglia outside CNS Spinal nerves Figure 49.4 Organization of Vertebrate Nervous System The spinal cord conveys information from and to the brain and also produces reflexes independently of the brain A reflex 反射動作 is the body's automatic response to a stimulus For example, a doctor uses a mallet to trigger a kneejerk reflex Quadriceps muscle Cell body of sensory neuron in dorsal root ganglion Gray matter White matter Figure 49.3 Hamstring muscle Spinal cord (cross section) Sensory neuron Motor neuron Interneuron 國立交通大學生物科技學系柯立偉老師 2
Different Neurons in Nervous System Glia in the Nervous System VENTRICLE Cilia CNS Neuron PNS Astrocyte Oligodendrocyte Schwann cell Microglial Capillary Figure 49.6 Glia have numerous functions to nourish 滋養, support, and regulate neurons. 國立交通大學生物科技學系柯立偉老師 3
Glia in the Nervous System Astrocyte ( 星形膠質細胞 ) It induce cells lining capillaries in the CNS to form tight junctions, resulting in a blood-brain barrier and restricting the entry of most substances into the brain. Microglia ( 小膠質細胞 ) Immune cells that protect against pathogen 病原體. Oligodendrocyte ( 少突膠質細胞 ) Generating myelinate 髓鞘 axon in the CNS, greatly increases the conduction speed of action potentials. Schwann cell Generating myelinate 髓鞘 axons in the PNS. Central Nervous System (CNS) Neuroanatomy and Development 大腦神經解剖與建置 國立交通大學生物科技學系柯立偉老師 4
Motivation The relationship between brain anatomy ( 解剖學 ) and cognition has been the source of fascination ( 魅力 ) and puzzlement ( 迷惑 ) for hundreds of years. 舉例來說, 許多研究認為大腦組織功能與智慧是有關聯的 ex. Albert Einstein To identify unique anatomical features of Einstein s brain that might explain his genius. When he died in 1955 at the age of 76, his brain was extracted and saved. weighed, perfused with formalin, measured and photographed sectioned and embedded in a material that permitted it to be thinly sliced to make histological slides for microscopic analysis To compare with the brains from a few dozen normal persons that had been donated for scientific research. IQ vs. Brain Organization 我的腦哪裡不一樣?? 國立交通大學生物科技學系柯立偉老師 5
Two Prominent Features of Einstein s Brain First: the Sylvian fissure ( 大腦側裂溝 ) (the division that separates the temporal lobe from the frontal and parietal lobes), in Einstein s brain had an unusual anatomical organization. Unlike the control brains, Einstein s brain showed a strange confluence ( 匯集處 ) of the Sylvian fissure with the central sulcus on the brain s lateral surface. The Sylvian fissure in most brains projects posteriorly ( 後面 ) to end in an area surrounded by the supramarginal gyrus ( 腦回邊界之上 ). Second: Einstein s inferior parietal lobe ( 下頂葉 ) was actually larger, and indeed thicker ( 較厚的 ) in lateral to medial extent. The increased size of Einstein s inferior parietal cortex might have been related to his intellectual capacity. (Hypothesis, not conclusion) From such investigations, hypotheses can be generated and then tested in brains removed at autopsy or, in the modern age of neuroimaging, in brains in the living human. Neuroanatomy the branch of anatomy that studies the anatomical organization of the nervous system Gross neuroanatomy : the focused is on general structures and connections visible to the naked eyes ( 裸眼 ) Microscopic neuroanatomy (fine neuroanatomy) : to describe the organization of neurons and their connections and subcellular structure 國立交通大學生物科技學系柯立偉老師 6
Methods in Neuroanatomy How to view the brain?? Removing the brain from the head and put it in a container filled with preservative ( 防腐劑 ) such as formalin ( 福馬林 ) Meninges ( 腦膜 ) a dense layers of collagenous fibers ( 膠原纖維 ) 硬腦膜 蛛網膜 軟腦脊膜 動脈 國立交通大學生物科技學系柯立偉老師 7
Meninges Both the brain and spinal cord are protected by a tough protective tissue called meninges consisting of three layers: Dura matter Arachnoid membrane Pia matter 15 The photograph of the human brain Cerebrum Brain stem cerebellum Spinal cord 國立交通大學生物科技學系柯立偉老師 8
Cerebrum Cerebrum gyrus (gyri) sulcus (sulci) Gyri ( 腦回 ): the protruding ( 突出 ) rounded surface Sulci ( 溝 ): the numerous smaller invaginations ( 堆疊 ) seen as creases ( 皺摺 ) 國立交通大學生物科技學系柯立偉老師 9
Cerebrum Three main anatomic planes 冠狀切 水平切 箭狀切 20 國立交通大學生物科技學系柯立偉老師 10
Navigating in the Brain The front is the rostral end, toward the frontal lobes. The posterior end is the caudal end, toward the occipital lobe. The top and bottom are, respectively, the dorsal and ventral surfaces of the brain. 腦 1.5kg average gyrus (gyri 複 ): 凸處迴轉 sulcus (sulci 複 ): 皺褶 ventricular: 腦室 20% 氧在腦缺氧 10 分即死身體動 / 不動腦中血液變化小 國立交通大學生物科技學系柯立偉老師 11
Different View of the Brain dorsal view ( horizontal axial section) 左 front 右 Interhemispheric fissure (longitudinal fissure) lateral view (sagittal section) frontal dorsal occipital occipital sylvian fissure( 裂溝 ) 區分 temporal lobe from frontal lobe 及 parietal ventral Central Nervous System (CNS) Brain Spinal Cord 國立交通大學生物科技學系柯立偉老師 12
Human Brain Development Embryonic brain regions Brain structures in child and adult Forebrain Midbrain Hindbrain Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon Cerebrum (includes cerebral cortex, white matter, basal nuclei) Diencephalon (thalamus, hypothalamus, epithalamus) Midbrain (part of brainstem) Pons (part of brainstem), cerebellum Medulla oblongata (part of brainstem) Midbrain Hindbrain Mesencephalon Cerebrum Metencephalon Diencephalon Myelencephalon Diencephalon Midbrain Forebrain Telencephalon Spinal cord Pons Medulla oblongata Cerebellum Spinal cord Embryo at 1 month Embryo at 5 weeks Child Figure 49.9b Overview of Our Brain Left cerebral hemisphere Cerebrum 大腦 Right cerebral hemisphere Cerebral cortex 大腦皮層 Corpus callosum 胼胝體 Basal nuclei 基底核 Figure 49.9d Cerebellum 小腦間腦 Diencephalon 視丘 Thalamus Figure 49.9c 松果體 Pineal gland 下視丘 Hypothalamus 腦下垂體 Pituitary gland Spinal cord 脊髓 腦幹 Brainstem Midbrain Pons 橋腦 Medulla oblongata 延腦 國立交通大學生物科技學系柯立偉老師 13
Cerebrum 大腦 The cerebrum is divided into right and left cerebral hemispheres, which receive information and control movement of the left and right body. A thick band of axons known as the corpus callosum 胼胝體 enables the right and left cerebral cortices to communicate. Basal nuclei 基底核 serve as centers for planning and learning movement sequences, deep within the white matter. Left cerebral hemisphere Cerebrum Right cerebral hemisphere Cerebral cortex Corpus callosum Basal nuclei Figure 49.9c Adult brain viewed from the rear Four Lobes: sylvian sulcus 國立交通大學生物科技學系柯立偉老師 14
Gray matter and White matter Gray matter and White matter The brain and spinal cord contain Gray matter, which consists of neuron cell bodies, dendrites, and unmyelinated axons White matter, which consists of bundles of myelinated axons Gray matter White matter Ventricles Figure 49.5 國立交通大學生物科技學系柯立偉老師 15
Primary sensory cortex for vision Brodmann area 17, BA 17 Striate cortex (cytoarchitectonic name) Calcarine cortex (gross anatomical name) Primary visual cortex (functional name), V1 (for visual area 1 ) 不同命名不一定都有一對一的對應區域 Ex. BA18 of the visual system, is not synonymous with V2. 國立交通大學生物科技學系柯立偉老師 16
Functions of Human Cerebral Cortex Figure 49.15 Frontal lobe Prefrontal cortex (decision making, planning) Motor cortex (control of skeletal muscles) Somatosensory cortex (sense of touch) Parietal lobe Sensory association cortex (integration of sensory information) Broca s area (forming speech) Visual association cortex (combining images and object recognition) Temporal lobe Auditory cortex (hearing) Wernicke s area (comprehending language) Cerebellum Occipital lobe Visual cortex (processing visual stimuli and pattern recognition) Motor Areas of the Frontal Lobe Frontal lobe: planning / execution of movements a. motor cortex : precentral gyrus =Motor strip 2 部分 primary motor cortex (M1): BA4 b. prefrontal cortex a* precentral gyrus:primary motor cortex 之前有 2 個 more main motor areas (within BA6). premotor cortex (lateral surface) supplementary motor cortex (dorsal to premotor area) * Axons in motor neurons extend to the spinal cord and brainstem * Synapse on motor neurons in the spinal cord b. prefrontal cortex (high-order association areas): higher aspects of motor control planning / execution of behaviors that require the integration of information over time 分 3 more areas: 1.dorsal lateral prefrontal cortex working memory 2.orbitofrontal cortex 3.anterior cingulate and medial front regions 國立交通大學生物科技學系柯立偉老師 17
Somatosensory Areas of the Parietal Lobe Parietal Lobe somatosensory cortex : central sulcus (posterior) and postcentral gyrus and adjacent areas. (BA 1, 2, and 3) 1.receive inputs from the somatosensory of the thalamus 2.represent information: touch, pain, 溫度, 四肢姿態的信息 (limb), 本體感受 (proprioception) 分為 SⅠ (primary somatosensory cortex ) SⅡ (secondary somatosensory cortex ) Two pathways: 外界 sensory signal anterolateral system (pain, 溫度 ) Thalamus SⅠ SⅡ dorsal column medial lemniscal system (touch, proprioception, movement) 國立交通大學生物科技學系柯立偉老師 18
Frontal lobe Parietal lobe Leg Hip Trunk Neck Head Knee Hip Toes Genitalia Jaw Tongue Primary motor cortex Tongue Pharynx Abdominal organs Primary somatosensory cortex Figure 49.17 國立交通大學生物科技學系柯立偉老師 19
Direct Stimulation on the Cortex Visual Processing Areas in the Occipital Lobe Retina Thalamus Lateral geniculate nucleus Colors/ 亮度 / 空間頻率 /orientation /movement (Details in Ch5 & 6) V1: primary visual cortex ( striate cortex) (Bradmann Area 17) 埋在 occipital lobe 的 calcarine fissure 中 primary visual pathway cortical projector (retinageniculo-striate pathway) Retina subcortical brain region superior colliculus of midbrain visuomotor functions ( 如眼動, eyemovents) secondary(2nd)visual pathway (subcortical projection) 國立交通大學生物科技學系柯立偉老師 20
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Auditory Processing Areas in the Temporal Lobe and Association Cortex Temporal Lobe (TL) Primary Auditory cortex: cochlea 耳蝸 (1) superior part of Temporal Lobe (BA 41 & 42) (2) buried ( 埋 ) in sylvian (lateral) fissure (tonotopic organization) subcortical relay Association Cortex BA 22 (surrounds the auditory cortex) aids in the perception of auditory inputs medial geniculate of thalamus Cortex 中非 sensory / motor 區 (Audio/video/ somatosensory 等 ), 皆為 association cortex, 如 front cortex / temporal cortex Ex:(1)visual association cortex ( 在 parietal 及 temporal lobes) (2)parietal-temporal-occipital junction 在左腦 :language processing 在右腦 :attentional orienting supratemporal cortex (Heschl s gyri) 國立交通大學生物科技學系柯立偉老師 22
Playing a Music 動覺 味覺 體感覺 嗅覺 聽覺 視覺 國立交通大學生物科技學系柯立偉老師 23
Language and Speech Studies of brain activity have mapped areas responsible for language and speech Broca's area in the frontal lobe is active when speech is generated Wernicke's area in the temporal lobe is active when speech is heard These areas belong to a larger network of regions involved in language Max Hearing words Seeing words Speaking words Generating words Min Figure 49.16 Review - Brain and its Functions 國立交通大學生物科技學系柯立偉老師 24
新皮質細皮質基底核間腦 Cingulate gyrus 扣帶迴 Hippocampus 海馬迴 (allocortex) Limbic lobe 邊緣葉 ( 系統 ) Limbic Lobe ( 邊緣葉 ) Limbic Lobe mesocortex 6 層 ( 如 cingulate gyrus) allocortex 1~4 層 ( 如 hippocampus) temporal / frontal /parietal / occipital lobes 6 層 neocortex ( 新皮質 ) 人類的新皮質 (neocortex) 佔整個腦的 76% 國立交通大學生物科技學系柯立偉老師 25
穹窿 ( 拱型空間 ) 前聯合喉 Classical Limbic Lobe: 1. cingulate Gyrus ( 扣帶迴 ) 2. hypothalamus ( 下視丘 ) 3. anterior thalamic nuclei ( 前丘腦核 ) 4. hippocampus ( 海馬迴 ) Papez Circuit: 1930 James Papez first suggested these structures were organized into a system for emotional behavior. Two key components of the Limbic system (today): amygdala ( 杏仁核 ), a group of neurons anterior to the hippocampus (orbitofrontal cortex + parts of basal ganglia + medial dorsal nucleus of thalamus, not shown here). 國立交通大學生物科技學系柯立偉老師 26
Limbic Lobe Hippocampus( 海馬迴 ) -inferior and media of temporal lobe - 分為 4 CA (cornu ammonis 大角 ) fields CA1~CA4 Entorhinal cortex 嗅皮質 cingulate cortex dentate gyrus hippocampus pyramidal nervous fornix 與 memory 及 emotional processing( 由於 hippocampus 與 cingulate mammillary bodies 與 limbic system 互連 ) papez circuit emotional behavior Amygdala( 核心 )+orbitofrontal cortex+(parts of) basal ganglia +medial dorsal nucleus of thalamus Limbic Lobe : 演化史上 neo cortex 老原始 與 emotional processing, learning, and memory 有關 Thalamus Emotions Generation and experience of emotions involve many brain structures including the amygdala 杏仁核, hippocampus 海馬迴, and parts of the thalamus 視丘, are grouped as the limbic system. The limbic system also functions in motivation, olfaction, behavior, and memory. Hypothalamus Olfactory bulb Figure 49.13 Amygdala Hippocampus 國立交通大學生物科技學系柯立偉老師 27
Emotions Generation and experience of emotion also require interaction between the limbic system and sensory areas of the cerebrum. The structure most important to the storage of emotion in the memory is the amygdala, a mass of nuclei near the base of the cerebrum. Nucleus accumbens Amygdala Happy music Sad music Figure 49.14 國立交通大學生物科技學系柯立偉老師 28
Basal Ganglia Basal Ganglia ( 腦部基底核 ) -subcortical structures ( 在側腦室 (lateral ventricles) 之前 ) - 在 control of movement 扮演重要的角色 - 細分成 3 部分 :(Fig 3.20, p80) globus pallidus ( 蒼白球 ) corpus caudate nucleus ( 尾狀核 ) striatum Putamen ( 硬核 ) neostriatum basal ganglia + subthalamic nucleus + substantia nigra (i) motor control [somatic motor and oculomotorsystems] (ii) cognitive functions : short-term memory process (dorsolaternal prefrontal cortex) execution functions (behaviors) The subthalamic nucleus ( 丘腦底部 ) and the substantia nigra ( 黑質 ) are considered part of the basal ganglia. Parkinson 與位於中腦 (midbrain) 的 substantia nigra 有密切關係, 因 substantia nigra 中生產 dopamine 的細胞大量死亡所致 國立交通大學生物科技學系柯立偉老師 29
Diencephalon ( 間腦 ) Diencephalon Thalamus Pineal gland Hypothalamus Pituitary gland Figure 49.9d Diencephalon ( 間腦 ) Incoming information from all the senses is sorted in the thalamus 視丘 and sent to the appropriate cerebral centers for further processing. Through the hypthalamus 下視丘 control of the pituitary gland 腦下垂體, it regulates hunger and thirst, plays a role in sexual and mating behavior, and controls the fight-or-flight response. It is also the source of posterior pituitary hormones and of releasing hormones that act on the anterior pituitary. The epithalamus includes the pineal gland 松果體 the source of melatonin. Diencephalon Thalamus Pineal gland Hypothalamus Pituitary gland Spinal cord Figure 49.9d 國立交通大學生物科技學系柯立偉老師 30
Diencephalon ( 間腦 ) Diencephalon ( 間腦 ) 含 thalamus (inner chamber 含意 ) 及 hypothalamus ( 下視丘 ) Massa intermedia 左 thalamus 左右連接 右 thalamus Thalamus ( 視丘 ) 座落於 brainstem 最前端 ( 蛋形 ) gateway to the cortex for the sensory systems ( 雙間 ) 亦參與 brainstem projection system ( 嗅覺 olfactory 除外 ) Fig. 3.24 Gross anatomy of the thalamus. This diagram shows the thalamus of the left and right hemispheres in a see-through brain. The thalamus is egg shaped. It serves as the gateway to the cortex for the sensory systems and contains reciprocal loops with all cortical regions, organized according to subdivisions of the thalamus. The thalamus also is innervated by brainstem projection systems. 國立交通大學生物科技學系柯立偉老師 31
Brainstem ( 腦幹 ) Brainstem Midbrain Pons 橋腦 Medulla oblongata 延腦 Figure 49.9d Brainstem ( 腦幹 ) The brainstem consist of the midbrain, the pons 橋腦 and the medulla oblongata 延腦. The midbrain coordinates visual reflexes, such as the peripheral vision reflex. A major function of the pons and medulla is to transfer information between the PNS and the midbrain and forebrain, also helping coordinate large-scale body movements, such as running and climbing. An additional function of the medulla is the control of several automatic, homeostatic functions, including breath, heart and blood vessel activity, swallowing 吞嚥, vomiting 嘔吐, and digestion 消化. Figure 49.9d Spinal cord Brainstem Midbrain Pons Medulla oblongata 國立交通大學生物科技學系柯立偉老師 32
Brainstem ( 腦幹 ) Diencephalon ( 間腦 ) cerebral cortex midbrain hindbrain pons medulla 控制 : (1)respiration( 呼吸 ) (2)consciousness (sleep/ wakeness) spinal cord Components of the Brainstem The pons 橋腦 : the upper segment of the brain stem It contains nerve fibers that connect the two halves of the cerebellum. It is vital in coordinating movements involving right and left sides of the body. The medulla oblongata 延腦 : the lower part of brain stem It transmits ascending and descending nerve fibers between the spinal cord and the brain. It also directly controls many involuntary muscular and glandular activities, including breathing, heart contraction, artery dilation, salivation, vomiting, and probably laughing. 國立交通大學生物科技學系柯立偉老師 33
Cerebellum ( 小腦 ) The cerebullem coordinates movement and balance and helps in learning and remembering motor skills. Receiving and integrating sensory information from the muscles and also monitors motor commands issue by the cerebrum during motor and perceptual functions. Left cerebral hemisphere Right cerebral hemisphere Cerebrum Figure 49.9c Adult brain viewed from the rear Cerebellum 國立交通大學生物科技學系柯立偉老師 34
Cerebellum ( 小腦 ) Cerebellum( 小腦 ) 包括 : (1)cerebellum cortex (2)4 對 deep nuclei (3)internal white matter =I/O 功能 : 維持 posture ( 姿態 ), walking, coordinated movement 小腦不直接控制 movements 而整合 body & motor commands 去 modify motor flow 產生 smooth 而協調的行為動作. Process of Movement Inputs (1)brain 中處理 motor/sensory 資料 ( 描述 body position) I/P cerebellum Deep nuclei O/P Thalamus (2)vestibular projection( 平衡 ) (3)audiory/visual inputs I/P brainstem spinal cord brainstem nucleus motor premotor cortex 國立交通大學生物科技學系柯立偉老師 35
Spinal Cord ( 脊椎神經 ) 在 medulla 到末梢神經 ( 全身 ) 之間 Ventral root 傳遞 final motor signal 到 muscles Dorsal root 傳遞 peripheral sensory info 到 brain Ventral Horn: contains the large motor neurons that project to muscles Dorsal Horn: contains sensory neurons and interneurons. at each level of spinal cord 存在 reflex pathway ( 如 knee-jerk reflex) 國立交通大學生物科技學系柯立偉老師 36