Central Nervous System

Limbic SystemLimbic System

边缘系统边缘系统

Introduction Introduction

CaseCase A 40-year-old woman awoke from sleep and complained to her A 40-year-old woman awoke from sleep and complained to her

husband of an indescribable unpleasant odor, nausea, and a panicky, husband of an indescribable unpleasant odor, nausea, and a panicky,

fearful sensation. During the following week, she had repeated fearful sensation. During the following week, she had repeated

stereotyped episodes of this kind followed by decreased stereotyped episodes of this kind followed by decreased

responsiveness and slow, inappropriate speech lasting 2 to 3 responsiveness and slow, inappropriate speech lasting 2 to 3

minutes. minutes.

As we shall see, As we shall see, limbic system abnormalities can cause abnormalities can cause

paroxysmal disorders as seen in this patient. In this chapter we will paroxysmal disorders as seen in this patient. In this chapter we will

learn about this important and diverse neural system and the learn about this important and diverse neural system and the

consequences of limbic system damage or dysfunction.consequences of limbic system damage or dysfunction.

HistoryHistory

Paul Broca (1824-1880): Paul Broca (1824-1880): a French pha French physician, surgeon,anatomist, and antysician, surgeon,anatomist, and anthropologist.hropologist. He is best known for his r He is best known for his research on Broca's area, a region of thesearch on Broca's area, a region of the frontal lobe that has been named afte frontal lobe that has been named after him. er him.

The term The term ““le grand lobe limbiquele grand lobe limbique””（边缘叶）（边缘叶） was first used by Broca was first used by Broca in 1878.in 1878.

James Papez (1883-1958):James Papez (1883-1958):

an American neuroanatomistan American neuroanatomist

He is most famous for his He is most famous for his

1937 description of the 1937 description of the Papez Papez

circuitcircuit which is a neural which is a neural

pathway in the brain thought pathway in the brain thought

to be involved in the cortical to be involved in the cortical

control of emotion. control of emotion.

Papez Circuit (Emotions)

Mammillary bodiesOther hypothalamic nuclei

Septal nucleiSubstantia innominata

(Basal nucleus of Meynert)

Hippocampal Formation(hippocampus

and dentate gyrus)Anterior Thalamic

nuclear group

Cortex of Cingulate GyrusParahippocampal Gyrus

Neocortex

FornixMammillothalamic

tract

Paul D. MacLean (1913-2007)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’‘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.

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.

What are the limbic system ?What are the limbic system ?

Anatomy of limbic systemAnatomy of limbic system

Core componentCore component: Hippocampus and amygdala.: Hippocampus and amygdala.

海马与杏仁核海马与杏仁核 Cortex: Cortex: Cingulated Cingulated ，， parahipocampal gyrus and prefrontal cortex. parahipocampal gyrus and prefrontal cortex.

扣带回、海马旁回与前额叶皮质扣带回、海马旁回与前额叶皮质 Nuclei: Nuclei: Hippocampus , septal nuclei Hippocampus , septal nuclei 隔核隔核 , amygdala,, amygdala,

Anterior and dorsomedial thalamus (Anterior and dorsomedial thalamus ( 丘脑前核和背内侧核丘脑前核和背内侧核 ),),

Hypothalamus- mammillary body (Hypothalamus- mammillary body ( 下丘脑下丘脑 -- 乳头体）乳头体） , ,

Ventromedial hypothalamus Ventromedial hypothalamus （下丘脑腹内侧部）（下丘脑腹内侧部） ..

Main components of the LIMBIC SYSTEM

The main circuit of Limbic SystemThe main circuit 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”

What are the main functions of Limbic What are the main functions of Limbic System?System?

The other important functions of limbic SystemThe other important functions of limbic System

Generates emotions (Emotional brain) Generates emotions (Emotional brain)

Add feeling to sensory experience which direct to Add feeling to sensory experience which direct to

behavior.behavior.

Affect: interpret the sensory experience as pleasant or Affect: interpret the sensory experience as pleasant or

unpleasant.unpleasant.

Memory and learning which is closely linked to emotion.Memory and learning which is closely linked to emotion.

Sexual behavior, emotions of rage ,fear, anxiety and Sexual behavior, emotions of rage ,fear, anxiety and

motivationmotivation

Part 1. Amygdaloid bodyPart 1. Amygdaloid body

• Amygdaloid bodyAmygdaloid body :

Large nuclear group in temporal lobe.Large nuclear group in temporal lobe.

Regions of the AmygdalaRegions of the Amygdala

Large basolateral region:Large basolateral region: 基底外侧核基底外侧核Provides direct input to basal ganglia and Provides direct input to basal ganglia and

motor system.motor system.

Small corticomedial group of nuclei:Small corticomedial group of nuclei: 皮质内侧核皮质内侧核Related to olfactory cortex.Related to olfactory cortex.

Central nuclei:Central nuclei: 中央核中央核Connected to hypothalamus.Connected to hypothalamus.

Amygdala ConnectionsAmygdala Connections

Cerebral cortexOlfactory system

ThalamusBrainstem reticular formation

Hypothalamus

AMYGDALA

Striaterminalis

Ventral Amygdalofugal fibers杏仁核腹侧通路

Amygdala InputsAmygdala Inputs

AMYGDALA

Corticomedial NuclearGroup

Basolateral NuclearGroup

Central Nucleus

OlfactorySystem

Temporal Lobe(associated with visual,auditory, tactile senses)

Brainstem (viscerosensory relayNuclei: solitary nucleus

and parabrachial nucleus)

VentralAmygdalofugal

Fibers

Amygdala OutputsAmygdala Outputs

AMYGDALA

Corticomedial NuclearGroup

Basolateral NuclearGroup

Central Nucleus

VentralAmygdalofugal

Fibers

Septal NucleiHypothalamus

Dorsal Medial Thalamic NucleusNucleus Accumbens

Hypothalamus

Nuclei ofANS

VentralAmygdalofugal

Fibers

Stria Terminalis

Functions of the AmygdalaFunctions of the Amygdala

Relate environmental stimuli to Relate environmental stimuli to coordinated behavioral autonomic and coordinated behavioral autonomic and endocrine responses seen in species-endocrine responses seen in species-preservation.preservation.

Responses include:Responses include:Feeding and drinkingFeeding and drinking

Agnostic (fighting) behaviorAgnostic (fighting) behavior

Mating and maternal careMating and maternal care

Responses to physical or emotional stresses.Responses to physical or emotional stresses.

Part 2. HippocampusPart 2. Hippocampus

Greek: “Sea Monster”Greek: “Sea Monster”

HippocampusHippocampus Any sensory stimulus will go to the hippocampus, and from Any sensory stimulus will go to the hippocampus, and from

there to the thalamus, hypothalamus and other limbic there to the thalamus, hypothalamus and other limbic

structures through structures through FORNIX FORNIX 穹窿穹窿 ..

Stimulation of hippocampus can cause pleasure, rage, sex Stimulation of hippocampus can cause pleasure, rage, sex

drive, etc.drive, etc.

Important feature of hippocampus is that it creates Important feature of hippocampus is that it creates

prolonged responseprolonged response

It has only three layered cortex.It has only three layered cortex.

It has role in learning and memoryIt has role in learning and memory

““ CC”” shaped structure in medial temporal lobe shaped structure in medial temporal lobe

From Digital Anatomist

Gross Anatomy and locationGross Anatomy and location

Morphology Morphology

Another terminology messAnother terminology mess Allocortex/ archicortex Allocortex/ archicortex 古皮质古皮质 Hippocampal formation Hippocampal formation 海马结构海马结构

Dentate gyrus Dentate gyrus 齿状回齿状回 Hippocampus Hippocampus 海马海马 ““Cornu ammonisCornu ammonis”” 阿蒙氏角阿蒙氏角 Subicular complex Subicular complex 下托下托 Entorhinal cortex Entorhinal cortex 内嗅皮质内嗅皮质

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

HippocampusHippocampus

Neocortex greatest developed in humanNeocortex greatest developed in human

Hippocampus of RatHippocampus of Rat

Development of HippocampusDevelopment of Hippocampus

From Digital Anatomist

From Digital Anatomist

CytoarchitectureCytoarchitecture

Human

Rodent

Two interlocking cell fields

• Dentate gyrus

• hippocampus

Hilus

CA1-CA3: pyramidal neurons

Dentate Gyrus: granule cells

sospslsr

ml

sl-m

•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

Intrinsic connectionsIntrinsic connections

Cajal, 1901Cajal, 1901

穿通纤维

谢弗侧支通路

苔藓纤维通路

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.

ConnectionsConnectionsAfferents:

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)

Two limbic AxisTwo limbic Axis

HippocampalHippocampal Extroceptive Extroceptive 外感受外感受 Cognitive processes-Cognitive processes-

learning and memory learning and memory 认知认知 Receive information from Receive information from

cortical sensory areascortical sensory areas Project to ant. ThalamusProject to ant. Thalamus Ant. Thalamus-cingulate Ant. Thalamus-cingulate

gyrus-hippocampus (Papez gyrus-hippocampus (Papez circuit)circuit)

Hippocampus-mammillary Hippocampus-mammillary body-thalamusbody-thalamus

Project to basal ganglionProject to basal ganglion Project to mid brain via Project to mid brain via

medial forebrain bundle.medial forebrain bundle.

AmygdaloidAmygdaloid IntroceptiveIntroceptive 内感受内感受 Generation of emotions, Generation of emotions,

motivational states motivational states 情感，动机情感，动机 Cortical sensory areas and Cortical sensory areas and

internal organsinternal organs Dorso medial thalamusDorso medial thalamus Dorso medial thalamus-Dorso medial thalamus-

prefrontal cortex-amygdala.prefrontal cortex-amygdala.

Amygdala –ventro medial Amygdala –ventro medial hypothalamushypothalamus

Project to basal ganglion.Project to basal ganglion. Project to mid brain via medial Project to mid brain via medial

forebrain bundle.forebrain bundle.

Part 3. HypothalamusPart 3. Hypothalamus

Limbic system and hypothalamusLimbic system and hypothalamus

Hypothalamus Hypothalamus 下丘脑下丘脑

Embryological Development of the Anterior and Posterior Pituitary

Peptidergic neuroendocrine cells:Peptidergic neuroendocrine cells: Magnocellular neuronsMagnocellular neurons

““ Large” neuronsLarge” neurons

Located in Located in paraventricularparaventricular and and supraoptic nucleisupraoptic nuclei

Secrete oxytocin and vasopressin into general Secrete oxytocin and vasopressin into general

circulation via circulation via posterior pituitaryposterior pituitary

OxytocinOxytocin uterine contraction & milk ejection uterine contraction & milk ejection

VasopressinVasopressin vasoconstriction, water vasoconstriction, water

resorption by the kidneyresorption by the kidney

““ small” neuronssmall” neurons

Located in medial basal region, arcuate and tuberal Located in medial basal region, arcuate and tuberal

nuclei, periventricular region, preoptic and nuclei, periventricular region, preoptic and

paraventricular nucleiparaventricular nuclei

Secrete releasing and inhibiting hormones into portal Secrete releasing and inhibiting hormones into portal

vasculature via anterior pituitaryvasculature via anterior pituitary

Nobel prize awarded to Nobel prize awarded to Guillemin (Salk), Schally and Guillemin (Salk), Schally and

YalowYalow in 1977 for their (independent) work in proving the in 1977 for their (independent) work in proving the

hypothesis that the hypothalamus releases hormones hypothesis that the hypothalamus releases hormones

that regulate the pituitarythat regulate the pituitary

Peptidergic neuroendocrine cells: Peptidergic neuroendocrine cells: Parvocellular neuronsParvocellular neurons

Portal veins of hypophysis

Hypothalamus pathwaysHypothalamus pathways

Afferent PathwayAfferent Pathway Projecting fromProjecting from

Median forebrain bundleMedian forebrain bundle Collaterals from other tractsCollaterals from other tracts

FornixFornix Hippocampus (to MB)Hippocampus (to MB)

Stria terminalisStria terminalis amygdalaamygdala

Efferent PathwayEfferent Pathway Projecting toProjecting to

hypothalamicohypophyseal hypothalamicohypophyseal (from supraoptic nuclei) (from supraoptic nuclei)

Neurohypophysis (pituitary)Neurohypophysis (pituitary)

Mammillothalamic tractMammillothalamic tract Anterior thalamic nucleusAnterior thalamic nucleus

Widespread projections to many brain regions, including the cerebral cortex, via histamine and hypocretin containing neurons in the tuberal region of the hypothalamus

Part 4. Cingulate gyusPart 4. Cingulate gyus andand Parahippocampal gyrus Parahippocampal gyrus

思考题思考题 简述边缘系统的研究历史简述边缘系统的研究历史 边缘系统包括哪些结构？核心结构是什么？边缘系统包括哪些结构？核心结构是什么？ 试述杏仁核的位置、核团分部、纤维联系及功能。试述杏仁核的位置、核团分部、纤维联系及功能。 试述海马的位置、分区、细胞构筑、内部通路及试述海马的位置、分区、细胞构筑、内部通路及外部纤维联系。外部纤维联系。

试述下丘脑的位置及其与神经内分泌的关系。试述下丘脑的位置及其与神经内分泌的关系。

Thanks !Thanks !