Brain Centers.2012

8/12/2019 Brain Centers.2012

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THE BRAIN

(ENCEPHALON)

1. What is the brain?

2. What are the main functions of the brain?

3. What are the main components of the

brain?4. How the brain works?

5. What are the general functions of thebrain?

6. WHAT ARE THE BRAIN CENTERS?


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?


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THE BRAIN:

MASTER ORGAN

ORGAN OF MIND

THE BRAIN

MIND

BEHAVIOR

IT IS THE BRAIN THAT

MAKES MAN A MAN


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CEREBRUM

Cortex

Divided into six lobes* each

contains 1. Outer layer of gray matter

(subtantia grisea/collections of cell

bodies: cerebral cortex)

2. Underlying white matter

(substantiaalba/collections of nervefibers) that convey information

to/from the cortex.

THE CEREBRUM:

2 cerebral hemispheres +

diencephalon (in between)

The largest part of the brain

1

2

34

*1. Frontal lobe

2. Parietal lobe

3. Temporal lobe

4. Occipital lobe

(5. Insular lobe

6. Limbic lobe)

Subst. alba

Subst. grisea


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CEREBRAL CORTEX

Handles the most

sophisticated functions

of the brain from

processing visual

images, thinking andplanning

CEREBRAL CORTEX* =

ORGAN OF

CIVILIZATION

Cerebral cortex layers (histology)

(*Neocortex: 6 layers)


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CORTEX

CEREBRUM

BRAIN

SUBST. ALBA

SUBCORTEX

BASAL GANGL.

CNS BRAIN STEM

CEREBELLUM

SPIN. CORD

C

E

RE

B

R

A

L

C

O

R

T

EX

L O B E S

1. FRONTAL

2. PARIETAL

3. OCCIPITAL

4. TEMPORAL

5. LIMBIC

6. INSULA

FP

O T

MAJOR REGIONS OF

THE HUMAN BRAIN


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CEREBRAL CORTEX

Insula (Lobus insularis)

Operculum


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Dorsolateral aspect

Medial aspect

THE BRAIN

- Lobes

- Cerebral hemisphere:

gyri, sulci

- Brain stem

- Cerebellum


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BRODMANN AREAS*

*Based on cytoarchitectonic structure of cerebral cortex

(important for brain functional mapping ): 52 areas


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BRAIN CENTERS

PARTS OF THE BRAIN(collections of nerve cells/neurons)THAT INVOLVE(control, regulate, modulate/modify,

integrate, associate) IN PARTICULAR FUNCTION (S)

TYPES OF CENTERS

1. According to their principal functions:

(1). SENSORY

(2). ASSOCIATIVE

(3). MOTOR 2. According to their location:

(1). Cortical (Areas)

(2). Subcortical (Nuclei)


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1. WHAT IS THE

BRAIN ?

LITTLE ABOUT THE BRAIN

The most important organ

Structures and functions: complicated

Delicate substance: firm jelly

Located in the cranial cavity

Cells: astronomical (1011

neurons* + 1012

neuroglia)Synapses: 1015 * Milky Way Galaxy (Rasi Bima Sakti)

Hundreds of neuronal pool/nuclei/centers


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Typical weight: 3 pounds (1,5 kg)

(2% of our body weight)

Consumes 20% of our energy (80%

of this energy consumption is

devoted to maintain the imbalance)

The active human brain consumes

about 20 watts of electrical energy

1 2 3

Well protected by:

1. Cranium (skull); 2. Meninges (coverings)

3. Cerebrospinal fluid (CSF); 4. Blood-brain barrier (BBB);

5. Circle of Willis (circulus arteriosus Willisi)

WHAT IS THE BRAIN? (cont.)


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1. Cranium (skull)

2. Meninges:

(1). Duramater

(2). Arachnoidea mater

(3). Pia materSubarachnoid space

(contains: CSF)

1

2

1

2

PROTECTION OF THE BRAIN


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PROTECTION OF THE BRAIN

Cranium: physical force/trauma

Dura mater: very tough tissue (not easily tobe torn)

Cerebrospinal fluid: distributes physicalforce

Blood-brain-barrier (BBB):prevents toxicagents/virus/bacteria enter the brain

Circulus arteriosus Willisi: helps to maintaincontinuous blood supply to the brain (if therewas disorder of blood flow to the brain)


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3. BLOOD-BRAIN BARRIER (BBB)

(barrier for toxin/chemical hazards

to the brain)

4.CIRCULUS ARTERIOSUS

WILLISI

(arterial circle of Willis: formed by

the branches of a. basillaris and a.

carotis interna)


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BRAIN CENTERS:

Collections/pools of nerve cells (neurons) in the brainwhich involve, control, regulate or integrate

one or more of the body functions

BRAIN:

EVALUATES

STOREINPUT

IS INFORMED BY SENSES

ABOUT PRESENCE OF

RESOURCES & HAZARDS

GENERATES

ADAPTIVE

RESPONSES

EXECUTEDBY EFFECTORS

(input)(output)


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WHAT ARE THE MAIN &

GENERAL FUNCTIONS OF

THE BRAIN ?

A.MAIN FUNCTIONS:

1. Serves as the control center

for functions of the body

2. Allows us to copewith

our environmentS

(1). To maintain the bodyhomeostasis

(2). To survive


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B. GENERAL FUNCTIONS OF THE BRAIN

1.MONITORS(through sensory system)

SOMATOSENSORY

SENSORY

VISCEROSENSORY

BRAIN

R

E

C

E

P

T

O

R

S

(1)

(2)


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2. COORDINATES

The brain :

PROCESSING PRODUCES APPROPRIATE

INTEGRATING RESPONSES

INFO.

3. INSTRUCTS(COMMANDS: (1).conscious; (2). unconscious)

Somatomotor Skeletal muscles

Motor Smooth muscles/

Visceromotor Viscera

Cardiac muscles

Blood vessels

Glandular cells

(1)

(2)

E

F

F

E

CT

O

R

S

BRAIN


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CENTRAL

NERVOUS

SYSTEM

(CNS)

INTERNAL

ENVIRONMENTEXTERNAL

ENVIRONMENT

AUTONOMIC

NERVOUS

SYSTEM

Sensory neurons

Motor neurons

Sensory neurons

Motor neurons

SOMATIC

NERVOUS

SYSTEM

CNS: brain + spinal cord

PNS: 12 pairs of cranial nerves + 31 pairs of spinal nerves

RECEPTORS

EFFECTORS

RECEPTORS

EFFECTORS


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DEVELOPMENT OF THE BRAIN

STAGES

1. Lamina neuralis

2. Tuba neuralis

3. Three vesicle stage*

4. Five vesicle stage

*(1). Prosencephalon(Fore brain) Cerebral hemisphere

Diencephalon

(2). Mesencephalon(Midbrain) Mesencephalon

(3). Rhombencephalon(After brain) Metencephalon

Myelencephalon


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MAJOR REGIONS OF THE HUMAN BRAIN

I. PROSENCEPHALON

Cerebrum: (1). Cerebralhemisphere (R+L):

cortex; basal ganglia

II.Diencephalon(thalamus,

hypothalamus)

III. MESENCEPHALON:

tegmentum; tectum

(superior & inferior

colliculi)

IV. RHOMBENCEPHALON

Pons

Medulla oblongata

Cerebellum* BRAIN STEM (truncs cerebri): DIENC.(T, HPT)+

MESENC. + RHOMBENC. (PONS + MED.OBL.)

I

IIIII

IV

Brain stem


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Based on the two theories)*, Stephens

& Price (2000) propose a model of

human brain evolution.

They argue the brain evolved in

four stages, leaving our brain with

three distinct regions:

1. REPTILIAN BRAIN2. PALEOMAMMALIAN BRAIN

(LIMBIC SYSTEM)

3. NEOMAMMALIAN BRAIN

(NEOCORTEX)

which reflect their ancestral

roots in terms of the types of

behaviours they contribute.

1

2

3

* McLean theory + Henry & Stephens theory


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OUR HUMAN BRAIN contains the

foundations of vertebrate brain

evolution:

1. Our REPTILIAN BRAIN(our lizard

legacy/warisan)

2. Our PALEOMAMMALIAN BRAIN(our

furry Lil Mammal)

3. Evolved later is ourHUMAN

RATIONAL BRAIN(Neocortex;

our Monkey mind)

4. And highly developed in the human isPREFRONTAL CORTEX

(our Higher Porpoise: Higher purpose)

(HIGHER COGNITIVE FUNCTIONS)


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Triune brain

(McLean)

1. Reptilian brain

(brain stem/truncus

cerebri)

2. Paleomammalian

brain (limbic system)

3. Neomammalian

brain (neocortex)


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Stevens & Price (2000) propose four

evolutionary developmental stages inthe human brain:

1. REPTILIAN BRAIN(brain stem, basal

ganglia, olfactostriatum, corpus

striatum):-The most primitive cerebral component containing

algorithms vital to maintaining life

- The behavioral responses at this level are largely

govern by instinct, such as defence, dominancestriving/berjuang, agonistic threat displays and mating

1.REPTILIAN: SURVIVAL

(-SELF PRESERVATION

- SPECIES PRESERVATION)


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2. LIMBIC (PALEOMAMMALIAN BRAIN)

(1). Cortical structures*

(2). Subcortical structures comprising thelimbic system, including the hippocampus,

hypothalamus, thalamus, amygdala, septal

nuc., accumbens nuc.)

- It controls self homeostasis,emotion, hunger, sexual desire, sleep

and memory

McLean draws attention to three forms of behaviour that

distinguishes the evolutionary transition from reptiles to mammals:nursing & maternal care, audiovocal communication between

mother-offspring, and play

2. LIMBIC: EMOTION

* Cortical structure: cingulate gyrus, isthmus, Hippocampal formation:

hippocampus, hippoc. gyrus, dentate gyrus, parahippoc. gyrus


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HIGHER-ORDER COGNITIVE FUNCTIONS

(Prefrontal Cortex/PFC):

- Planning - Attention

- Prediction - Working memory

- Decision making - Logical reasoning

- Problem solving - Intelligence

- Creative thinking - etc.


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Three maincomponents of

the brain:

1. Cerebrum

2. Cerebellum

3. Brain stem(Truncus cerebri)


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LOCATION OF THE BRAIN CENTERS

(spreading all over the brain)

2. CEREBELLUM 3. BRAIN STEM

(TRUNCUS CEREBRI)1. CEREBRUM

(1). CORTICAL

(AREAS)

(2). SUBCORTICAL

(NUCLEI) (1)

(2)

23


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COMPLEXITY OF THE

HUMAN BRAIN

FUNCTIONS

ABSTRACT THOUGHT

CONCRETE THOUGHT

AFFILIATION

ATTACHMENT

(love/affection)

SEXUAL BEHAVIOR

EMOTIONAL REACTIVITY

MOTOR REGULATION

APPETITE/SATIETY

AROUSAL

SLEEP

BLOOD PRESSURE

HEART RATE

BODY TEMPERATURE

CO

M

P

L

E

X

I

T

Y

OFFUNCTION


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THREE MAIN COMPONENTS OF THE BRAIN

1. CEREBRUM

(TELENCEPHALON)*

(The largest and most

developmentally advanced

part of the brain)

* Responsible for severalhigher functions

(higher intellectual

function, speech, emotion,

integration of sensorystimuli of all types,

initiation of the final

common pathways for

movement & fine controlof movement

fMRI

functional Magnetic

Resonance Imaging


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CEREBRUM (cont.)


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LATERALIZATION

LEFT & RIGHT CEREBRAL

HEMISPHERES (CHs)

LEFT CH

Controls the majority functions on the right

side of the body

(Slightly more developed)

RIGHT CH

Controls most of the

functions on the left side

of the body

BRAIN FUNCTIONS IN GENERAL:

(1). Conscious thought processes & intellectual functions

(2). Memory storage & processing

(3). Conscious & subconscious regulation

of skeletal muscle contraction


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RIGHT & LEFT BRAIN

(LATERALIZATION/

DOMINANCE)

Right Brain:

Emotional/art brain

Left Brain:

Rational/mathematic brain

Language dominance

(+/- 90% of pop.

Right handed persons: 95%)


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BRAIN CENTERS ON THE CEREBRAL CORTEX

(4)(3,1,2)

(9,10,11,12)

(44,45)

(17,18,19)

(39)

Dorsolateral face of the brain


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1. Motor cortex (4):

involved in

conscious thought

and controls the

voluntary movement

of the body

2. Somatosensorycortex (5,7):receives

and processes

sensory signals

from the body

3. Visual cortex(17,18,19):receives

and process signals

from the retinas of

the eyes

12

3


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1. Corpus callosum

(a large band of nerve

fibers through which

info. Flows back andforth between the left

and the right

hemisphere of the

brain

2. Thalamus(the relay

station for most info.

going into the brain

3. Hypothalamus

(regulates sexhormones, blood

pressure and body

temperature)

1

2

3

4 5 6

7

8

Medial face of the brain


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4. Amygdala

(regulates the heart beat

and other visceral

functions and processesthe emotion fear)

5. Hippocampus(helps

establish long-term

memory to regions of

the cerebral cortex:

memory consolidation)

6. Pons & medulla

(control of breathing,

circulation, heartbeat,and digestion)7. Cerebellum(essential for

coordination of movement, balance)

8. Basal ganglia(a control system for

movement & cognitive function)

45

6

7

8


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2. BRAIN STEM (TRUNCUS CEREBRI)

- The final pathway between cerebral

structures and the spinal cord- Responsibles for a variety of

autonomic functions (control of

respiration, heart and blood

pressure, wakefullness, arousal& attention)

DIENCEPHALON

A. THALAMUS:

Relay & processing centers for

sensory information

AB

CD

E

3A. Thalamus; B. Hypothalamus; C.

Midbrain; D. Pons; E. Med. obl.)


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B. HYPOTHALAMUS

1. Centers controlling:

- emotions- autonomic functions

- hormones production

2. Controls stereotyped motorpatterns (behaviors) related to:

- eating

- drinking

- sexual activity

3. Modifies respiratory reflexes

B


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C. MESENCEPHALON (MIDBRAIN)

(1). Processing of visual & auditory data

(a). receives visual info.: superior

colliculus ; (b). receives auditory

info.: inferior colliculus

(2). Generation of reflective somatic

motor responses

(3). Maintenance of consciousness:

reticular formation/RAS (Reticular

Activating System)

(4). Connects the forebrain to the hind

brain (assists in transmission of

impulses)

(a)

(b)

C

MESENC.:1. TEGMENTUM (ventral)

2. TECTUM (dorsal) aqueduct


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D. PONS (METENCEPHALON)

(1). Relays sensory info. to

cerebellum & thalamus

(2). Subconscious somatic &

visceral motor system

E. MEDULLA OBLONGATA

(MYELENCEPHALON)

(1). Relays sensory info. to

thalamus & to other portions

of the brain stem

(2). Autonomic centers for

regulation of visceral function: - cardiovascular

- respiratory

- digestive system

D

E

C

3 CEREBELLUM (METENCEPHALON)


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3. CEREBELLUM (METENCEPHALON)

(The second largest area of the brain)

Responsibles for maintaining balance and

further control of movement andcoordination, and body position)

(1). Coordinates complex somatic motor

patterns

(2). Adjusts output of other somatic motorcenters in brain & spinal cord

3

3

Cerebellum

cortex (Archi-/A, Paleo-/P & Neocortex/N)

Subcortical ( nuclei):

- Nuc. fastigii (A: balance)

-Nuc. emboliformis + globosus (P: muscle tonus)

- Nuc. dentatus (N: coordination)


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CEREBRAL CORTEX:

Frontal, Parietal, Occipital, Temporal lobes

(consist of several functional areas)

CEREBRAL CORTEX

(52 Brodmann Areas based on

cytoarchitechture of the cortex)


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Primary motor (4)

Primary sensory (3,1,2)

Motor association area

(Premotor area: 6,8)

Prefrontal cortex (PFC)

(9,10,11,12)

Speech center (Broca) (44,45)

Auditory cortex (41,42)

Auditory association (22)

General interpretative area

(Wernicke) (39)

Sensory assoc.area (5,7)

Visual assoc. area (19)

Visual cortex (17,18)

CORTICAL CENTERS/AREAS


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LIMBIC SYSTEM

I. Cortical components (limbic lobe):Cingulate gyrus, isthmus, hippocampal

formation (hippocampus, gy. hippoc.,

gy. parahippoc., subiculum, dentate gy.)

2. Subcortical components (nuclei):

amygdala, septal nuclei, mammillary

body,

preoptic nuc., hypothal., thalamus)

BASAL GANGLIA (NUCLEI BASALES):

(- lenticular nuc.: globus pallidus, putamen;

- caudate nuc.: caput, corpus, cauda)


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LANGUAGE AREAS/ZONE

(95% ON THE LEFT CH)

1. Brocas area

(motor/expressive

speech area)(44,45)

2. Wernickes area(sensory/receptive area)

Arcuate fasciculus: a band

of nerve fibers that

connects Wernickes area

with Brocas area

Gangguan bahasa (aphasia): 1. Aphasia

Broca,;2. Aphasia Wernicke; 3. Aphasia arcuata


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LANGUAGE AREAS/ZONE

Geschwind proposed this anatomical

model showing the successive

participation of several brain areas asa person speaks a written words

M t C t i l d i S t t


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Motor Cortex: involved in

conscious thought and controls

the voluntary movement of body

parts

Somatosensory cortex:

receives and processes

sensory signals from the

body

Visual cortex: receives

and processes signals

from the retinas of the

eyes


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TO UNDERSTAND MAN WE HAVE TO STUDY THE BRAIN

Brain Centers.2012

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