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Central Nervous System

Central Nervous System. Limbic System 边缘系统. Introduction. Case.

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Central Nervous System

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  1. Central Nervous System Limbic System边缘系统

  2. Introduction

  3. Case A 40-year-old woman awoke from sleep and complained to her husband of an indescribable unpleasant odor, nausea, and a panicky, fearful sensation. During the following week, she had repeated stereotyped episodes of this kind followed by decreased responsiveness and slow, inappropriate speech lasting 2 to 3 minutes. As we shall see, limbic system abnormalities can cause paroxysmal disorders as seen in this patient. In this chapter we will learn about this important and diverse neural system and the consequences of limbic system damage or dysfunction.

  4. History Paul Broca (1824-1880): a French physician, surgeon,anatomist, and anthropologist. He is best known for his research on Broca's area, a region of the frontal lobe that has been named after him. The term “le grand lobe limbique”（边缘叶）was first used by Broca in 1878.

  5. James Papez (1883-1958): an American neuroanatomist He is most famous for his 1937 description of the Papez circuit which is a neural pathway in the brain thought to be involved in the cortical control of emotion.

  6. Papez Circuit (Emotions) Mammillothalamic tract Fornix Mammillary bodies Other hypothalamic nuclei Septal nuclei Substantia innominata (Basal nucleus of Meynert) Hippocampal Formation (hippocampus and dentate gyrus) Anterior Thalamic nuclear group Neocortex Parahippocampal Gyrus Cortex of Cingulate Gyrus

  7. Paul D. MacLean (1913-2007) an American physician and neuroscientist who made significant contributions in the fields of physiology, psychiatry, and brain research. The term ‘limbic system’ was first used by MacLean in 1952 to describe a set of structurally and functionally related structures of the brain bordering the midline, inner surface of each cerebral hemisphere.

  8. What are the limbic system ? The LIMBIC SYSTEM includes diverse cortical and subcortical structures located mainly in the medial and ventral regions of the cerebral hemispheres. These structures are unified by their evolutionarily ancient origins, and they constitute the major portion of the forebrain in many species. Only in higher mammals has the larger neocortical mantle surpassed the limbic system in size.

  9. Anatomy of limbic system

  10. Main components of the LIMBIC SYSTEM • Core component: Hippocampus and amygdala. 海马与杏仁核 • Cortex: Cingulated ，parahipocampal gyrus and prefrontal cortex. 扣带回、海马旁回与前额叶皮质 • Nuclei: Hippocampus , septal nuclei 隔核 , amygdala, Anterior and dorsomedial thalamus (丘脑前核和背内侧核), Hypothalamus- mammillary body (下丘脑-乳头体）, Ventromedial hypothalamus （下丘脑腹内侧部）.

  11. The main circuit of Limbic System

  12. What are the main functions of Limbic System? The functions of the limbic system are also ancient, and they play an important role for survival in the animal kingdom. Limbic functions can be divided into the following four basic categories: 1. Homeostatic functions 稳态, including autonomic and neuroendocrine control 2. Olfaction 嗅觉 3. Memory 记忆 4. Emotions and drives “HOME”

  13. The other important functions of limbic System • Generates emotions (Emotional brain) • Add feeling to sensory experience which direct to behavior. • Affect: interpret the sensory experience as pleasant or unpleasant. • Memory and learning which is closely linked to emotion. • Sexual behavior, emotions of rage ,fear, anxiety and motivation

  14. Part 1. Amygdaloid body

  15. Amygdaloid body: • Large nuclear group in temporal lobe.

  16. Regions of the Amygdala • Large basolateral region:基底外侧核 Provides direct input to basal ganglia and motor system. • Small corticomedial group of nuclei:皮质内侧核 Related to olfactory cortex. • Central nuclei:中央核 Connected to hypothalamus.

  17. Amygdala Connections Cerebral cortex Olfactory system Thalamus Brainstem reticular formation Hypothalamus Stria terminalis AMYGDALA Ventral Amygdalofugal fibers 杏仁核腹侧通路

  18. Amygdala Inputs Olfactory System AMYGDALA Corticomedial Nuclear Group Temporal Lobe (associated with visual, auditory, tactile senses) Basolateral Nuclear Group Central Nucleus Brainstem (viscerosensory relay Nuclei: solitary nucleus and parabrachial nucleus) Ventral Amygdalofugal Fibers

  19. Amygdala Outputs Stria Terminalis Septal Nuclei Hypothalamus AMYGDALA Corticomedial Nuclear Group Dorsal Medial Thalamic Nucleus Nucleus Accumbens Hypothalamus Basolateral Nuclear Group Central Nucleus Ventral Amygdalofugal Fibers Nuclei of ANS Ventral Amygdalofugal Fibers

  20. Functions of the Amygdala • Relate environmental stimuli to coordinated behavioral autonomic and endocrine responses seen in species-preservation. • Responses include: Feeding and drinking Agnostic (fighting) behavior Mating and maternal care Responses to physical or emotional stresses.

  21. Part 2. Hippocampus

  22. Greek: “Sea Monster”

  23. Hippocampus • Any sensory stimulus will go to the hippocampus, and from there to the thalamus, hypothalamus and other limbic structures through FORNIX 穹窿. • Stimulation of hippocampus can cause pleasure, rage, sex drive, etc. • Important feature of hippocampus is that it creates prolonged response • It has only three layered cortex. • It has role in learning and memory

  24. “C” shaped structure in medial temporal lobe Gross Anatomy and location From Digital Anatomist

  25. Morphology • Another terminology mess • Allocortex/ archicortex 古皮质 • Hippocampal formation 海马结构 • Dentate gyrus 齿状回 • Hippocampus 海马 “Cornu ammonis”阿蒙氏角 • Subicular complex 下托 • Entorhinal cortex 内嗅皮质

  26. Hippocampus 1- hippocampal body 2 – head and digitationes hippocampi 3 – hippocampal tail 4 – fimbria (fornix)海马伞 5 – fornix穹隆 6 – subiculum下托

  27. Neocortex greatest developed in human

  28. Hippocampus of Rat

  29. Development of Hippocampus From Digital Anatomist From Digital Anatomist

  30. Cytoarchitecture • Two interlocking cell fields • Dentate gyrus • hippocampus Human Rodent

  31. so sp • Stratum oriens 始层 • Stratum pyramidale 锥体层 • Stratum lucidum 透明层 • Stratum radiatum 辐射层 • Stratum lacunosum-moleculare 网状分子层 sl sr sl-m ml Hilus CA1-CA3: pyramidal neurons Dentate Gyrus: granule cells

  32. Intrinsic connections 穿通纤维 苔藓纤维通路 谢弗侧支通路 Cajal, 1901

  33. hippocampal Network: The hippocampus forms a principally uni-directional network, with input from the Entorhinal Cortex (EC) that forms connections with the Dentate Gyrus (DG) and CA3 pyramidal neurons via the Perforant Path (PP). CA3 neurons also receive input from the DG via the Mossy Fibres (MF). They send axons to CA1 pyramidal cells via the Schaffer Collateral Pathway (SC), as well as to CA1 cells in the contralateral hippocampus via the Associational Commisural (AC)Pathway. CA1 neurons also receive inputs direct from the Perforant Path and send axons to the Subiculum (Sb). These neurons in turn send the main hippocampal output back to the EC, forming a loop.

  34. Connections • Afferents: • Much of cortex is reciprocally connected to entorhinal cortex 内嗅皮质 • Cholinergic and GABA input via septal nuclei 隔核 • Amygdala • VTA 中脑腹侧被盖区, LC蓝斑, Raphe n. 中缝核 • Efferents • Via the fornix 穹隆 • Precommissural: septal nuclei • Post-commisural: mammillary bodies (to anterior thalamic nucleus via mammillothalamic tract)

  35. Hippocampal Extroceptive 外感受 Cognitive processes-learning and memory 认知 Receive information from cortical sensory areas Project to ant. Thalamus Ant. Thalamus-cingulate gyrus-hippocampus (Papez circuit) Hippocampus-mammillary body-thalamus Project to basal ganglion Project to mid brain via medial forebrain bundle. Amygdaloid Introceptive内感受 Generation of emotions, motivational states 情感，动机 Cortical sensory areas and internal organs Dorso medial thalamus Dorso medial thalamus-prefrontal cortex-amygdala. Amygdala –ventro medial hypothalamus Project to basal ganglion. Project to mid brain via medial forebrain bundle. Two limbic Axis

  36. Part 3. Hypothalamus

  37. Limbic system and hypothalamus

  38. Hypothalamus 下丘脑

  39. Embryological Development of the Anterior and Posterior Pituitary

  40. Peptidergic neuroendocrine cells: Magnocellular neurons • “Large” neurons • Located in paraventricular and supraoptic nuclei • Secrete oxytocin and vasopressin into general circulation via posterior pituitary • Oxytocin uterine contraction & milk ejection • Vasopressin vasoconstriction, water resorption by the kidney

  41. Peptidergic neuroendocrine cells: Parvocellular neurons • “small” neurons • Located in medial basal region, arcuate and tuberal nuclei, periventricular region, preoptic and paraventricular nuclei • Secrete releasing and inhibiting hormones into portal vasculature via anterior pituitary • Nobel prize awarded to Guillemin (Salk), Schally and Yalow in 1977 for their (independent) work in proving the hypothesis that the hypothalamus releases hormones that regulate the pituitary

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