ZPeople only use 10% of their brain zPeople are either right-brained or left- brained which explains...

People only use 10% of their brain People are either right-brained or left-

brained which explains their natural abilities

Everything people have ever experienced is stored somewhere in their brain

At birth people have all the neurons that they will ever have

Modern Myths…

Human Brain

About 3 pounds 78% water, 10%

fat, 8% protein Less than 2.5% of

body’s weightUses 20% of

body’s energy

Amazing Brain Numbers

100 billion neurons

1 trillion glial cells

1,000 trillion synaptic connection points

280 quintillion memories

Techniques for studying the brain1. brain stimulation2. lesions3. CT scan (formerly CAT scan)4. PET scan5. MRI scan6. fMRI scan

Fig. 2.10 The functions of brain structures are explored by selectively activating or removing them. Brain research is often based on electrical stimulation, but chemical stimulation is also used at times.

Table of ContentsTable of Contents ExitExit

Brain lesion experimentally destroys brain tissue to study animal behaviors after such destruction.

“deposits” in the brain bank

Clinical observations help explain a number of brain disorders.

Alterations in brain changes due to neurological and psychiatric diseases are now being catalogued.

Electroencephalogram (EEG)

An amplified recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalp.

Electroencephalogram (EEG)Hearing in a baby

Electroencephalogram (EEG)

beta

delta

theta

alpha

Brain Imaging

CT (computed tomography) Scana series of X-ray photographs

taken from different anglescombined by computer into a

composite representation of a slice through the body

also called CAT scan

Fig. 2.12 An MRI scan of the brain.

© Huntington Magnetic Resonance Center, Pasadena, California


this CAT scan shows extremely severe atrophy. The black areas should be white (cerebral cortex) and…

there is very little cerebral cortex

Whose brain is this???

Terri Schiavo: vegetative state 1990 - 2005-heart attack related to bulimia

Positron-Emission Tomography PET Scan

A method for analyzing biochemical activity in the brain, using injections of a glucose-like substance containing a radioactive element

Active areas have increased blood flowSensors detect radioactivity because

active areas consume glucose rapidlyDifferent tasks show distinct activity

patterns

PET Scan

PET Brain Scan

PET scan to identify depression and Alzheimer’s Disease

Magnetic Resonance Imaging (MRI)Method for studying body and brain tissue

using magnetic fields and radio frequencies

Magnetic fields alight certain ions/compoundsWhen field is removed, molecules release

energy as radio wavesComputer calculates tissue density from radio

wavesProvides clear 3D image

MRI Scan

Top images show ventricular enlargement in a schizophrenic patient.

Functional MRI images

This image shows brain regions when a participants lies.

Anterior Cingulate Cortex: active w/conflicting urges

Hindbrain (continuation of the spinal cord)- medulla- reticular formation- pons-cerebellum

Midbrain (above the hindbrain)-small area between hindbrain and forebrain to relay info eyes, ears and skin that controls certain automatic behaviors

Forebrain (front part of the brain)-most highly developed part of brain-responsible for most complex aspects of behavior – thinking and decision making

Older Brain Structures

Brainstem the oldest part of the brain, beginning where the spinal cord swells and enters the skull. Responsible for automatic survival functions.

Parts of the Brain StemPons

Involved in sleeping, waking, dreaming relay station for the cerebral cortex and the

medullaMedulla

Responsible for certain automatic functions (breathing, heart rate)

Reticular Activating System Arousal/alertness

Cerebellumthe “little brain” attached to the rear of the

brainstemRegulates balance and coordination of

movementPlays a part in: Analyzing sensory info Solving problems Understanding words

Thalamus

the brain’s sensory switchboard, located on top of the brainstem.

Relays incoming sensory messages (except olfactory) to higher areas (cerebral cortex)

transmits outgoing motor signals

Thalamus

Limbic Systema doughnut-shaped system of neural structures

at the border of the brainstem and cerebrum

• associated with emotions such as fear, aggression

• drives for food and sexIncludes

Amygdala Hypothalamus Hippocampus

The Limbic System

When the limbic system is manipulated rat will navigate fields or climb up a tree

Brain stimulation to reward for turning right or left!!

The Amygdala two almond-shaped neural clusters linked to

emotion of fear and anger.Responsible for:

Arousal Regulation of emotion

Involved in: Emotional memory Influence fear & aggression

psychosurgery in humans reduces rage but has devastating after effectsunethical

Stimulate the Amygdala

Hypothalamus & Pituitary GlandHypothalamus

Involved in emotions and drives vital to survival (hunger, sex)

Regulates autonomic nervous system

Pituitary Gland Small endocrine gland which

releases hormones and regulates other endocrine glands

Governed by hypothalamus

Hypothalamus neural structure lying below (hypo) the

thalamus; directs maintenance activitiesEating, drinking, body temperatureventromedial hypothalamus – satiety center: causes us to stop eating when stimulated. (“stop” button) If area is destroyed, eat unless we are deprived of food.

lateral hypothalamus - hunger center causes us to eat when stimulated. (“start”) If area destroyed, no hunger, and we will starve to death unless forced to eat.

Hypothalamus

Hypothalamus - Motivation

Rats cross an electrified grid for self-stimulation, when electrodes are placed in the reward (hypothalamus) center

The Hippocampus“Gateway to memory”Responsible for:

Storage of new information in memory Comparing sensory information with what

the brain expects about the world Enabling us to form spatial memories for

navigating the environment

Hippocampus

Cerebral Cortex

Cerebral Cortex

Cerebral Cortex - The outermost layer of gray matter making up the superficial aspect of the cerebrum.

•The body’s ultimate control and information processing center.

The Cerebral Cortex

• Glial Cells cells in the nervous system that

support, nourish, and protect neurons

Front of the Brain Back of the Brain

Cerebral Features:

• Sulci – Small grooves dividing the gyri– Central Sulcus – Divides the Frontal Lobe from the Parietal Lobe

• Fissures – Deep grooves, generally dividing large regions/lobes of the brain

– Longitudinal Fissure – Divides the two Cerebral Hemispheres– Transverse Fissure – Separates the Cerebrum from the Cerebellum– Sylvian/Lateral Fissure – Divides the Temporal Lobe from the Frontal and Parietal Lobes

• Gyri – Elevated ridges “winding” around the brain.

Gyri (ridge)

Fissure

(deep groove)

Sulci (groove)

http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif

Longitudinal Fissure

Transverse Fissure

Sylvian/Lateral Fissure

Central Sulcus

http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg http://www.dalbsoutss.eq.edu.au/Sheepbrains_Me/human_brain.gif

Specific Sulci/Fissures:

Cerebrum -The largest division of the brain. It is divided into two hemispheres, each of which is divided into four lobes.

CerebrumCerebrum

Cerebellum


The CerebrumLargest brain structureTwo cerebral hemispheres connected by

the corpus callosumSurrounded by cerebral cortex (thin

layers of cells – gray matter)Responsible for higher forms of thinking2 cerebral hemispheres separated by

longitudinal fissure (L/R hemispheres)

The cerebrum receives all info from the senses (except smell)

In charge of most sensory, motor, and cognitive processes

The Cerebral CortexLobes of the Brain (4)

FrontalParietalOccipitalTemporal

http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

Brain divided into 4 regions or lobes

Lobes of the Brain - FrontalThe frontal lobe of the brain is located top front part of

the skull• It plays an integral role in the following functions/actions:

- Memory Formation- Emotions- Decision Making/Reasoning

- Personality

Investigation (Phineas Gage)

- involved in speaking; muscle movement motor cortex (Broca’s)

Frontal Lobe - Cortical Regions

• Broca’s Area – controls facial neurons, speech, and language comprehension. •located on Left frontal lobe.

– Broca’s Aphasia – Results in the ability to comprehend speech, but the decreased motor ability (or inability) to speak and form words.

Lobes of the Brain - Parietal LobeThe parietal lobe of the brain is located behind the

frontal lobe

• plays major role in following functions/action:

- Spatial awareness and perception(Proprioception - Awareness of body/ body parts in space and in relation to each other)

Pleasure, pain, touch, temperature include the sensory cortex

Parietal Lobe - Cortical Regions

Primary Somatosensory Cortex – Site involved with processing of tactile and proprioceptive information.

- Assists with the integration and interpretation of sensations relative to body position and orientation in space.

Lobes of the Brain – Occipital Lobe

• Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Occipital Lobe – Cortical Regions

Primary Visual Cortex – This is the primary area of the brain responsible for sight -recognition of size, color, light, motion, dimensions, etc.

• Visual Association Area – Interprets information acquired through the primary visual cortex.

Primary Visual Cortex

Visual Association Area

Regions

Visual Function

Functional MRI scan shows the visual cortex activated as the subject looks at faces

Lobes of the Brain – Temporal LobeThe temporal lobes are located on the sides of

the brain• play an integral role in the following functions:

- Hearing- Organization andcomprehension of language

Temporal Lobe – Cortical Regions

Primary Auditory Cortex – Responsible for hearing

• Wernicke’s Area – language comprehension. located on the left temporal lobe.

- Wernicke’s Aphasia – Language comprehension is inhibited. -Words and sentences not clearly understood, and sentence formation may be inhibited or non-sensical.

Primary Auditory Cortex

Wernike’s Area

Primary Olfactory Cortex (Deep)Conducted from Olfactory Bulb

Regions

Auditory FunctionFunctional MRI scan shows the auditory cortex is activate in patients who hallucinate.

Click the Region to see its Name

Lobes and Structures of the Brain

B. A.

C.

D. E.

F.

G.


Lobes and Structures of the Brain

B.

A. (groove)

C. (groove)

D. E.

F.

G.

B. Frontal Lobe

G. Parietal Lobe

F. Occipital Lobe

D. Temporal Lobe

A. Central Sulcus

(groove)

E. Transverse Fissure

C. Sylvian/Lateral Fissure


Cortical RegionsA.

B.

C.

D.E. F.

G.

H.

I.

J.K.


Cortical Regions

A.

B.

C.

D.E. F.

G.

H.

I.

J.K.

A. Primary Motor Cortex/ Precentral Gyrus

B. Broca’s Area

C. Orbitofrontal Cortex

K. Primary Somatosensory Cortex/ Postcentral Gyrus

I. Primary Gustatory Cortex

J. Somatosensory Association Cortex

G. Primary Visual Cortex

H. Visual Association Area

E. Primary Auditory Cortex

F. Wernike’s Area

D. Primary Olfactory Cortex (Deep)


Functions of the Cortex

Motor Cortex: area at the rear of the frontal lobes controls voluntary movements. Sensory Cortex: (parietal cortex) receives information from skin surface and sense organs.

The Cerebral Cortex

A: Primary Motor Cortex

* This graphic representation of the regions of the Primary Motor Cortex and Primary Sensory Cortex is one example of a HOMUNCULUS: Homunculus

Q: What do you notice about the proportions depicted in the homunculus?

Q: What is meant by depicting these body parts in such outrageous proportions?

A: They are not depicted in the same scale representative of the human body.

A: These outrageous proportions depict the cortical area devoted to each structure.

Back-Hom.

* Note: Homunculus literally means “little person,” and may refer to one whose body shape is governed by the cortical area devoted to that body region.

Auditory FunctionFunctional MRI scan shows the auditory cortex is activate in patients who hallucinate.

Association Areas More intellegent animals have

increased “uncommitted” or association areas of the cortex

Language Problems in the Brain

Aphasia is an impairment of language, usually caused by left hemisphere damage either to Broca’s area (impaired speaking) or Wernicke’s area (impaired understanding).

Broca’s Area an area of the left frontal lobe that directs the muscle movements involved in speech

Wernicke’s Area an area of the left temporal lobe involved in language comprehension and expression

Specialization & IntegrationBrain activity when hearing, seeing, and speaking words – association areas

Phineas Gage

Gage was a railroad construction foremanAn 1848 explosion forced a steel tamping

rod through his headOthers said he was “no longer Gage” –

previously mild-mannered/friendly and became ill-tempered and undependable

Lost his job, worked as a sideshow exhibitLearned frontal lobe effects personality

Brain Reorganization

Plasticity the brain’s capacity for modification,

as evident in brain reorganization following damage

especially in children other brain areas learn to control

functions

Our Divided Brain

Our brain is divided into two hemisphere

Left hemisphere processes reading, writing, speaking, mathematical, comprehension skills

termed as the dominant brain in the 1960

Right hemisphere is typically responsible for spatial relationships and analyses

Defining Left & Right Brain FunctionsLeft Brain

Analytical, data side Prove it to me! Left brained people are programmers, engineers,

most project managers, “techy types”…Right Brain

Abstract, free flowing Anything is possible! Right-brained people are artists, musicians,

dancers, writers. “free thinkers”.Balanced Brain

Combining the best of both

•A number of brain scan studies have shown normal individuals engage their right brain when they engage in a perceptual task, (see it)•and •left brain when carrying out a linguistic task (say it)

Hemispheric Lateralization

Q: Assuming this comical situation was factually accurate, what Cortical Region of the brain would these doctors be stimulating?

Copyright: Gary Larson

Fig. 2.21 The left and right brain have different information processing styles. The right brain gets the big pattern; the left focuses on small details.


Left Brain / Right Brain Functions

Left Brain works with Right Brain works with:

Logic

Words

Parts and specifics

Analysis (breaking apart)

Sequential thinking

Tends to be time-bound

Governs right side of your body

Emotions

Pictures

Wholes/relationships among parts

Synthesis (putting together)

Simultaneous and holistic thinking

Tends to be time free

Governs left side of your body

Higher levels of norepinephrine Higher levels of dopamine

LOOK at the chart on the right say the word from left to rt. (make many mistakes?)Now say the color…(make many now???)The left brain will try to say the color while the right brain will read the word!

If the woman appears to be rotating clockwise you tend to be right brain dominant.

If the woman appears to be rotating counter-clockwise you tend to be left brain dominant.

If the woman seems to change the direction of her rotation back and forth you are one of those rare individuals who use both side of their brain equally.

We all, of course, what hand we are…when we hold a pen, but how far does this bias extend throughout your body?

Are you left-eared? Left eyed? Let’s have some fun...For a change!!!

Imagine the centre of your back is itching. Which hand do you scratch it with?

Interlock your fingers. Which thumb is uppermost?

Imagine you are applauding. Start clapping your hands. Which hand is uppermost?

Wink at an imaginary friend straight in front of you. Which eye does the winking?

Put your hands behind your back, one holding the other. Which hand is doing the holding?

Someone in front of you is shouting but you cannot hear the words. Cup your ear to hear better. Which ear do you cup?

Count to three on your fingers, using the forefinger of the other hand. Which forefinger do you use?

Fixate a small distant object with your eyes and point directly at it with your forefinger. Now close one eye. Now close other eye.

Which eye was open when the fingertip remained in line with the small object?

(When the other eye, the non-dominant one, is open and the dominant eye is closed, the finger will appear to move to one side of the object.)

Lateralization of FunctionDamage to the corpus callosum interferes

with the exchange of information between right and left hemispheres.

Epilepsy is a condition characterized by repeated episodes of excessive synchronized neural activity. Mainly due to decreased release of the

inhibitory neurotransmitter GABA.Physicians once cut the corpus callosum to

prevent seizures

Divided Brain – Split brain

Corpus Callosum

Split Brain Procedurethe two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them.

Lateralization of FunctionRoger Sperry (1974) revealed subtle

behavioral differences for split brain people.Because the left side of the brain is dominant

for language in most people, most split brain people: Have difficulty naming objects briefly

viewed in the left visual field.But yet can touch the object w/ left hand!!

Visual input with split-brain – Roger Sperry and others

Lateralization of Function

The left half of each retina connects to the left hemisphere (right visual field)

The right half of each retina connects to the right hemisphere (left visual field)

Half of the axons from each eye cross to the opposite side of the brain at the optic chiasm.

Split-Brain Experiment

Subjects were presented information to one or the other side of their brains (right: hammer/left: cow)

Patients identified verbally the pictures to the right visual field (hammer)

When patients were asked to point to the image seen on left, patients point to the picture on left w/left hand (cow)

Our Divided Brain With the corpus

callosum severed, objects (apple) presented in the right visual field can be named.

Objects (pencil) in the left visual field cannot

But left hand can touch it!!

Split Brain

Split-Brain Experiment

Try drawing two shapes with both of you hands simultaneously.

BB

C

Phantom Limb Syndromehttp://www.youtube.com/watch?v=8AcDXnzmsMc

http://nobelprize.org/educational/medicine/split-brain/index.html

http://www.youtube.com/watch?v=MZnyQewsB_Y

Brain Structures and their Functions

Fig. 2.25 This simplified drawing shows the main structures of the human brain and describes some of their most important features. (You can use the color code in the foreground to identify which areas are part of the forebrain, midbrain, and hindbrain.)


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