The limbic system Neuronal circuitry controls of emotional behavior and motivational drives Neuronal...

The limbic systemThe limbic system

Neuronal circuitry Neuronal circuitry controls of emotional controls of emotional behavior and motivational behavior and motivational drivesdrives

Composed of subcortical and Composed of subcortical and cortical componentscortical components

Limbic SystemLimbic System

Figure 12.18

limbiclimbic

Subcortical Subcortical groupgroup

Hypothalamus ,septum,paraolfactHypothalamus ,septum,paraolfactory area,epithalamus,ant.thalamic ory area,epithalamus,ant.thalamic nuclei,hippocampus,amygdala,basnuclei,hippocampus,amygdala,bas

al gangelial gangeli

Limbic cortexLimbic cortex

Orbitofrontal Orbitofrontal coretx,subcallosal gyrous coretx,subcallosal gyrous

cingulate gyrus and cingulate gyrus and parahippocamp gyrousparahippocamp gyrous

Limbic System: Emotion Limbic System: Emotion and Cognitionand Cognition

The limbic system interacts with the The limbic system interacts with the prefrontal lobes, therefore:prefrontal lobes, therefore: One can react emotionally to conscious One can react emotionally to conscious

understandingsunderstandings One is consciously aware of emotion in One is consciously aware of emotion in

one’s lifeone’s life Hippocampal structures – convert Hippocampal structures – convert

new information into long-term new information into long-term memoriesmemories

The hypothalamus not The hypothalamus not only influences how you only influences how you feel, it influences how feel, it influences how

you interpret the you interpret the consequences of those consequences of those

feelings.feelings.

limbiclimbic

VisceralAfferents

Nucleusof the

Solitary Tract

Brain StemNuclei

AutonomicPreganglionic

Nuclei

HormonalOutput

AutonomicOutput

TargetOrgans

HypothalamicNuclei

Hypothalamic Role in Emotion

Hypothalamus

PituitaryReleasing Factors

AutonomicNervous System

Adenohypophysis(Anterior Pituitary)

Neurohypophysis(Posterior Pituitary)

Sympathetic

Parasympathetic

“I feel fear!”

Hypothalamus

AmygdalaAmygdala

Cortex, Cortex, septumseptum

medial forebrain

bundle

Amygdala Amygdala ventral

routeBrainstemBrainstemspinal cordspinal cord

medial

forebrain

bundle

stria

terminalis

Anterior NucleusAnterior Nucleusmtt

BrainstemBrainstemdorsal long.

fasciculus

post.post.magno

(SO, PV)ant.ant.parvo

PituitaryPituitary

Hypothalamus,MajorHypothalamus,Major

Hypothalamus is the most important Hypothalamus is the most important output sorce output sorce

It communicate with brain stem by It communicate with brain stem by medial forebrain medial forebrain bundle ,bidirectionaly between bundle ,bidirectionaly between forebrain and brain stem forebrain and brain stem

Hypothalamus cont.Hypothalamus cont.

Controls: Controls: 1-vegetative and 1-vegetative and endocrine functions 2-endocrine functions 2-behavior and motivationbehavior and motivation

vegetative and endocrine vegetative and endocrine functionsfunctions

Cardiovascular regulation involves Cardiovascular regulation involves 1-Post. And lateral 1-Post. And lateral hypothalamus area, increase BP and hypothalamus area, increase BP and HR. HR. 2-preoptic area ,decrease BP and HR 2-preoptic area ,decrease BP and HR *1and 2 mediated by *1and 2 mediated by cardiovascular centre in the pontile cardiovascular centre in the pontile and medullary part of reticular and medullary part of reticular formation formation

Body temperature Body temperature regulationregulation

Preoptic area Preoptic area

Thermo-regulation Thermo-regulation (body temperature)(body temperature)

Involves autonomic nervous, endocrine, Involves autonomic nervous, endocrine, and skeletomotor systemsand skeletomotor systems

Body temperature detectorsBody temperature detectors Peripheral: skin, spinal cord, visceraPeripheral: skin, spinal cord, viscera Central: anterior hypothalamusCentral: anterior hypothalamus

Body temperature effectorsBody temperature effectors Heat retention or generation: Heat retention or generation:

posterior hypothalamusposterior hypothalamus Heat dissipation: anterior Heat dissipation: anterior

hypothalamushypothalamus

Thermo-regulation Thermo-regulation (body temperature)(body temperature)

Heat dissipating mechanismsHeat dissipating mechanisms Dilation of blood vessels in the skin Dilation of blood vessels in the skin Inhibition of shiveringInhibition of shivering

Heat conserving mechanismsHeat conserving mechanisms Vasoconstriction of blood vessels in Vasoconstriction of blood vessels in

the skinthe skin Shivering Shivering Increased secretion of thyroxinIncreased secretion of thyroxin

Methods of thermo-regulation by the body

Response to Cold Response to Heat

Regulation of body water Regulation of body water intakeintake

Thirst centre,lateral hypothalamusThirst centre,lateral hypothalamus Electrolyte concentrationmaking Electrolyte concentrationmaking

desire to drinkdesire to drink Supraopticx:urinary excrition due to Supraopticx:urinary excrition due to

ADH ADH

ThirstThirst

Function of serum osmolality and blood Function of serum osmolality and blood volumevolume

Osmotic receptors in the hypothalamusOsmotic receptors in the hypothalamus Volume receptors in the right atrium of Volume receptors in the right atrium of

the heart and great veinsthe heart and great veins Vasopressin release from hypothalamusVasopressin release from hypothalamus

Increases water reabsorption from Increases water reabsorption from the kidneythe kidney

Inhibited by ethanolInhibited by ethanol

Circadian RhythmCircadian Rhythm Oscillations during the course of the dayOscillations during the course of the day

CorticosteriodsCorticosteriods

Feeding and drinking behaviorFeeding and drinking behavior

Growth hormone secretionGrowth hormone secretion

Lesions of the suprachiasmatic nuclei of Lesions of the suprachiasmatic nuclei of

the hypothalamus disrupts these the hypothalamus disrupts these oscillationsoscillations

Control of Feeding

FeedingFeeding Complex interaction of many systemsComplex interaction of many systems Regulation of energy metabolism by the Regulation of energy metabolism by the

Ventromedial and Lateral nuclei of the Ventromedial and Lateral nuclei of the hypothalamushypothalamus Physical Lesions produce hyperphagia and Physical Lesions produce hyperphagia and

obesity or reduced attention to food.obesity or reduced attention to food. Amygdala may also be involved indirectlyAmygdala may also be involved indirectly

Lesions produce hyperphagia-like symptomsLesions produce hyperphagia-like symptoms Ventromedial hypothalamic lesions also cause Ventromedial hypothalamic lesions also cause

increased insulin secretion Obesity.increased insulin secretion Obesity.

Feedback Mechanisms Feedback Mechanisms Controlling FeedingControlling Feeding

Feedback from gut hormonesFeedback from gut hormones e.g. Cholecystokinine.g. Cholecystokinin

Released from small intestine in Released from small intestine in response to feedingresponse to feeding

Inhibits or suppresses feedingInhibits or suppresses feeding

Uterine contraction and Uterine contraction and milk ejectionmilk ejection

Oxytocin stimulation by Oxytocin stimulation by PARAVENTRICULAR PARAVENTRICULAR

هسته آميگدال و ارتباط آن با نواحي مختلف مغز

ارتباطات عصبي سيستم ليمبيك

ارتباطات اصلي شكنج سينگوال

مسيرهاي پردازش اطالعات

Hippocampus circuitHippocampus circuit

Ent. cortex From perforant To Ent. cortex From perforant To dentate gyrous mossy fiber cA3 dentate gyrous mossy fiber cA3 schaffer collaterals cA1 to subiculum schaffer collaterals cA1 to subiculum to ento cortex to ento cortex