The Brain

The Brain• Made up of

neurons • 23 billion nerve

cells and 300 trillion synapses

• Glial cells –

My husband is my glial cell. He takes care of me!!! Whose yours?

Ways we Study the Brain

Accidents

Phineas Gage • Personality

changed after the accident.

What did this tell us?• That different part

of the brain control different aspects of who we are.

Lesions

• Frontal Lobotomy

Electroencephalogram• EEG• Detects brain

waves through their electrical output.

• Used mainly in

Computerized Axial Tomography

• CAT Scan• 3D X-Ray of

the brain.

Magnetic Resonance Imaging

• MRI

Positron Emission Tomography

• PET Scan

Functional MRI• Identifies most active areas of the brain

during a specific mental task

Brain Structures

• Scientists divide the brain up into three parts.

Brain Regions• – medulla, pons, reticular

formation, thalamus, cerebellum

• Hippocampus, Amygdala, Hypothalamus

• frontal lobe, parietal lobe, temporal lobe, occipital lobe,

Brain Stem• Part of the brain with the

oldest ancestry• 5 Regions:

– Medulla– Pons– Reticular formation– Thalamus– Cerebellum

Limbic System

• EMOTIONAL CONTROL CENTER of the brain.

• REWARD CENTER of the brain (hypothalamus)

• Located between the brainstem and cerebral hemispheres

• Made up of Hypothalamus, Amygdala and Hippocampus.

Areas of the Cerebral Cortex

• Divided into eight lobes, four in each hemisphere

Figure 3B.13 Left hemisphere tissue devoted to each body part in the motor cortex and the sensory cortex As you can see from this classic though inexact representation, the amount of cortex devoted to a body part is not proportional to that part’s size. Rather, the brain devotes more tissue to sensitive areas and to areas requiring precise control. Thus, the fingers have a greater representation in the cortex than does the upper arm.

© 2011 by Worth Publishers

Association Areas• Locate in cerebral cortex • Not directly involved in sensory

and motor activity (sensory cortex, motor cortex, visual cortex or auditory cortex)

• Involved in higher mental functions such as

• Example:

Figure 3B.16 Areas of the cortex in four mammals More intelligent animals have increased “uncommitted” or association areas of the cortex. These vast areas of the brain are responsible for integrating and acting on information received and processed by sensory areas.

© 2011 by Worth Publishers

Language Development• Aphasia –

• Frontal Lobe– Broca’s Area –

• Temporal Lobe– Wernicke’s Area –

• Parietal Lobe

– Angular Gyrus –

The Divided Brain

• Plasticity –

• .• The younger you are, the more plastic

your brain is.• Contraint induced therapy - teaching a

patient to regain the use of an impaired limb by limiting the use of the good limb

• Neurogenesis – What can you do to producenew neurons?

Hemispheres• Brain Lateralization -

divided into a left and right hemisphere.

• Contralateral controlled- left controls right side of body and vice versa.

• Left Brain –

• Right Brain –

Split-Brain Patients

• Sperry and Gazzaniga • Corpus Callosum –

connects two brain hemispheres and carries messages between them

• Removed in patients with severe epilepsy

• When removed you have a split-brain patient.

Figure 3B.22 The information highway from eye to brain Information from the left half of your field of vision goes to your right hemisphere, and information from the right half of your visual field goes to your left hemisphere, which usually controls speech. (Note, however, that each eye receives sensory information from both the right and left visual fields.) Data received by either hemisphere are quickly transmitted to the other across the corpus callosum. In a person with a severed corpus callosum, this information sharing does not take place.

© 2011 by Worth Publishers

Figure 3B.23 Testing the divided brain When an experimenter flashes the word HEART across the visual field, a woman with a split brain

However, if asked to indicate with her left hand what she saw,

.

From Gazzaniga, 1983

Figure 3B.25 Which one is happier? Look at the center of one face, then the other. Does one appear happier?

The Brain and Consciousness

• Consciousness –

• Dual Processing –