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 Surgical destruction of the brain tissue Lobotomy - consists of cutting the connections to and from the prefrontal cortex, the anterior part of the frontal lobes of the brain

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 Concentration of glucose Radioactivity decays rapidly, so limited to monitoring short tasks Maps areas of the brain responsible for specific activities such as movement or speech

Functional MRI Identifies most active areas of the brain during a specific mental task Identify regions of the brain that handle pain

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, Oldest to newest Regions In more evolved creatures are the limbic system and cerebral cortex Cerebral cortex - most highly developed part of the human brain – responsible for thinking and information processessing

Brain Stem Part of the brain with the oldest ancestry 5 Regions: Medulla Pons Reticular formation Thalamus Cerebellum NOT consciously aware of brain stems functions secretary of all the functions your body needs to stay alive, like breathing air, digesting food, and circulating blood. secretarye of all the functions your body needs to stay alive, like breathing air, digesting food, and circulating blood. In charge of all of the functions your body needs to stay alive ie. Breathing, digestions, blood circulation, controls involuntary muscles – stomach heart, Brains secretary – sorts through all of the messages that brain and rest of body send back and forth

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. Only mammals and humans have a limbic system – gives us capability for emotions and memory Drug addiction and cravings are associate with the limbic systems pleasue

Areas of the Cerebral Cortex Divided into eight lobes, four in each hemisphere The association areas—areas that are free to process all kinds of information Association areas are located in the cerebral cortex Regions not assoc with motor and sensory cortex ¾ of cortex is Uncommitted to sensory or muscular activity (motor cortex or sensory cortex) Association areas – involved in higher mental functions such as learning, remembering, thinking and speaking Ex. Enables you to recognize me as your favorite teacher! Anticipate you will receive a detention for your bad behavior in class or suspended for drinking at a football game Know that you will get called down to Short’s office if you are fighting in the hallway

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 Temporal Lobe Broca’s Area – Temporal Lobe Wernicke’s Area – Parietal Lobe Angular Gyrus – Aphasia – impairment of language caused usually by a stroke Subfunctions of speech are produced in different areas of the brain Broca’s - Involved in controlling speech = left frontal lobe Wernicke’s – involved in understanding and producing meaningful speech – left temporal lobe Angular gyrus – enables you to read aloud

The Divided Brain Plasticity – . Neurogenesis – 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 – Functions of one brain area taking over the functions of another damaged brain area Constraint induced therapy – Teaching a patient to regain the use of an impaired limb by limiting his or her use of the good limb rewire damaged brains by forcing patients to use a nonfunctioning limb. Feeling the existance of an amputated part of the body is a result of brain plasticity Neurogenesis - Recent brain research contradicts previously held beliefs, indicating that new neurons are actually formed in the brain. Physical exercise, sleep and exposure to stimulating environments can help to form new neurons Christopher Reeves was able to regain some functioning in his lungs and fingers (moved finger on national television) = some hope for neurogenisis if spinal cord damaged What can you do to produce new 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 – Brain lateralization – specialization of each hemisphere recognize faces with right hemisphere, but not left Perceive an optical illusion – right hemisphere Read facial emotion – right hemisphere Adding a series of numbers – left brain What certain words have in common – inferences Left handedness = genes or prenatal factors may influence, but identical twins are unlikely to share meaning…not likely genetic

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. Corpus callosum – quickly transfers info from one side of the brain to others Psychologist Michael Gazzaniga asked split-brain patients to stare at a dot as he flashed HE·ART on a screen. HE appeared in the left visual field, ART in the right. When asked, patients said they saw ART Psychologist Michael Gazzaniga asked split-brain patients to stare at a dot as he flashed HE·ART on a screen. HE appeared in the left visual field, ART in the right. When asked to point to the word with their left hand, patients pointed to HE Can simultaneously copy different figures with the right and left hand

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 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 Dual Processing –