Central Nervous System

Limbic SystemLimbic System

边缘系统边缘系统

IIntroduction ntroduction

HistoryHistoryPaul Paul BrocaBroca (1824(1824--1880): 1880): a a FrenchFrenchphysicianphysician, , surgeonsurgeon,,anatomistanatomist, and , and anthropologistanthropologist.. He is best known for He is best known for his research on his research on Broca's areaBroca's area, a region , a region of the of the frontal lobefrontal lobe that has been that has been named after him. named after him.

The term The term ““le grand lobe le grand lobe limbiquelimbique””（边缘叶）（边缘叶）was first used by was first used by BrocaBrocain 1878.in 1878.

James James PapezPapez (1883(1883--1958):1958):an an AmericanAmerican neuroanatomistneuroanatomist

He is most famous for his He is most famous for his 1937 description of the 1937 description of the PapezPapezcircuitcircuit which is a which is a neuralneuralpathway in the pathway in the brainbrain thought thought to be involved in the to be involved in the corticalcorticalcontrol of control of emotionemotion. .

Papez Circuit (Emotions)Mammillary bodies

Other hypothalamic nucleiSeptal nuclei

Substantia innominata(Basal nucleus of Meynert)

Hippocampal Formation(hippocampus

and dentate gyrus)Anterior Thalamic

nuclear group

Cortex of Cingulate GyrusParahippocampal Gyrus

Neocortex

Fornix Mammillothalamictract

Paul D. MacLean (1913Paul D. MacLean (1913--2007)2007)

an American physician and neuroscientist who made significant contributions in the fields of physiology, psychiatry, and brain research.

The term ‘‘limbic systemlimbic 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 main circuit of Limbic SystemThe main circuit of Limbic System

Anatomy of limbic systemAnatomy of limbic system

What are the components of What are the components of limbic system ?limbic system ?

Core component: hippocampus and amygdala.Core component: hippocampus and amygdala.

Cortex: Cingulated and prefrontal cortex.Cortex: Cingulated and prefrontal cortex.

Nuclei: hippocampus , septal , amygdala.Nuclei: hippocampus , septal , amygdala.

Anterior and dorsomedial thalamusAnterior and dorsomedial thalamus

HypothalamusHypothalamus-- mammillary body and mammillary body and ventromedial hypothalamus.ventromedial hypothalamus.

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

Preservation of self (Homeostatic) and species Preservation of self (Homeostatic) and species (Reproduction).(Reproduction).

Visceral brain, less concerned with external Visceral brain, less concerned with external environment environment

Responsible for internal and emotional aspect Responsible for internal and emotional aspect of our behavior.of our behavior.

What are the other important What are the other important functions of limbic System?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

ComponentsComponents

AmygdaloidAmygdaloid body body 杏仁体杏仁体

Hippocampus (Hippocampus (““seahorseseahorse””) ) 海马海马

Hypothalamus Hypothalamus 下丘脑下丘脑

ParahippocampalParahippocampal gyrusgyrus 海马旁回海马旁回

CingulateCingulate gyusgyus 扣带回扣带回

MamillaryMamillary bodies bodies 乳头体乳头体

Anterior nucleus of thalamus Anterior nucleus of thalamus 丘脑前核丘脑前核

Part 1. Part 1. AmygdaloidAmygdaloid bodybody

• AmygdaloidAmygdaloid bodybody :

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

Regions of the Regions of the AmygdalaAmygdala

Large Large basolateralbasolateral region: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 Small corticomedialcorticomedial group of nuclei: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.

AmygdalaAmygdala ConnectionsConnectionsCerebral cortex

Olfactory systemThalamus

Brainstem reticular formation

Hypothalamus

AMYGDALA

Striaterminalis

Ventral Amygdalofugalfibers

AmygdalaAmygdala InputsInputs

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

AmygdalaAmygdala OutputsOutputs

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 Functions of the AmygdalaAmygdalaRelate environmental stimuli to Relate environmental stimuli to coordinated behavioral autonomic and coordinated behavioral autonomic and endocrine responses seen in speciesendocrine responses seen in species--preservation.preservation.Responses include:Responses include:

Feeding and drinkingFeeding and drinkingAgnostic (fighting) behaviorAgnostic (fighting) behaviorMating and maternal careMating and maternal careResponses to physical or emotional stresses.Responses to physical or emotional stresses.

Part 2. HippocampusPart 2. Hippocampus

Greek: Greek: ““Sea MonsterSea Monster””

HippocampusHippocampusAny 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 FORNIXFORNIX..

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 lobeshaped structure in medial temporal lobe

From Digital Anatomist

Gross Anatomy and locationGross Anatomy and location

MorphologyMorphology

Another terminology messAnother terminology messAllocortexAllocortex/ / archicortexarchicortex 古皮质古皮质

HippocampalHippocampal formation formation 海马结构海马结构

Dentate Dentate gyrusgyrus 齿状回齿状回

Hippocampus Hippocampus 海马海马

““CornuCornu ammonisammonis”” 阿蒙氏角阿蒙氏角

SubicularSubicular complex complex 下托下托

EntorhinalEntorhinal cortex 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 Development of HippocampusHippocampus

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

sospsl

sr

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

CajalCajal, 1901, 1901

hippocampal Network: The hippocampus forms a principally uni-directional network, with input from the Entorhinal Cortex (EC) that forsms 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 reciprocallyconnected to entorhinal cortex内嗅皮质Cholinergic and GABA inputvia septal nuclei 隔核AmygdalaVTA 中脑腹侧被盖区, LC蓝斑,Raphe n. 中缝核

EfferentsVia the fornix 穹隆Precommissural: septal nucleiPost-commisural: mammillarybodies (to anterior thalamic nucleus via mammillothalamictract)

Two limbic AxisTwo limbic AxisHippocampalHippocampal

ExtroceptiveExtroceptive 外感受外感受

Cognitive processesCognitive processes--learning and memory learning and memory 认知认知

Receive information from Receive information from cortical sensory areascortical sensory areasProject to ant. ThalamusProject to ant. ThalamusAnt. ThalamusAnt. Thalamus--cingulate cingulate gyrusgyrus--hippocampus (Papez hippocampus (Papez circuit)circuit)HippocampusHippocampus--mammillarymammillarybodybody--thalamusthalamusProject to basal ganglionProject to basal ganglionProject to mid brain via Project to mid brain via medial forebrain bundle.medial forebrain bundle.

AmygdaloidAmygdaloidIntroceptiveIntroceptive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 organsDorso medial thalamusDorso medial thalamusDorso medial thalamusDorso medial thalamus--prefrontal cortexprefrontal cortex--amygdala.amygdala.

Amygdala Amygdala ––ventroventro medial medial hypothalamushypothalamusProject to basal ganglion.Project to basal ganglion.Project to mid brain via Project to mid brain via medial forebrain bundle.medial forebrain bundle.

Part 3. HypothalamusPart 3. Hypothalamus

Limbic system and hypothalamusLimbic system and hypothalamus

Hypothalamus Hypothalamus 下丘脑下丘脑

PeptidergicPeptidergic neuroendocrineneuroendocrine cells:cells:MagnocellularMagnocellular neuronsneurons

““LargeLarge”” neuronsneurons

Located in Located in paraventricularparaventricular and and supraopticsupraoptic nucleinuclei

Secrete Secrete oxytocinoxytocin and vasopressin into general and vasopressin into general circulation via posterior pituitarycirculation via posterior pituitary

OxytocinOxytocin uterine contraction & milk ejectionuterine contraction & milk ejection

Vasopressin vasoconstriction, water Vasopressin vasoconstriction, water resorptionresorption by the kidneyby the kidney

““smallsmall”” neuronsneuronsLocated in medial basal region, Located in medial basal region, arcuatearcuate and and tuberaltuberalnuclei, nuclei, periventricularperiventricular region, region, preopticpreoptic and and paraventricularparaventricular nucleinucleiSecrete releasing and inhibiting hormones into portal Secrete releasing and inhibiting hormones into portal vasculature via anterior pituitaryvasculature via anterior pituitaryNobel 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

PeptidergicPeptidergic neuroendocrineneuroendocrine cells:cells:ParvocellularParvocellular neuronsneurons

Portal veins of hypophysis

Hypothalamus pathwaysHypothalamus pathwaysAfferent PathwayAfferent Pathway Projecting fromProjecting fromMedian forebrain bundleMedian forebrain bundle Collaterals from other tractsCollaterals from other tracts

FornixFornix Hippocampus (to MB)Hippocampus (to MB)

StriaStria terminalisterminalis amygdalaamygdala

Efferent PathwayEfferent Pathway Projecting toProjecting tohypothalamicohypophysealhypothalamicohypophyseal(from (from supraopticsupraoptic nuclei) nuclei)

NeurohypophysisNeurohypophysis (pituitary)(pituitary)

MammillothalamicMammillothalamic tracttract 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. Part 4. CingulateCingulate gyusgyus andandParahippocampalParahippocampal gyrusgyrus

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 !