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THE BRAIN

THE BRAIN. September 18, 2013. Ways we Study the Brain 52-54. CAT Scan PET Scan MRI Functional MRI. Lesions. Removal or destruction of some part of the brain. Frontal Lobotomy. What IS IT?. Jellylike mass of fat and protein Weighs about 3 pounds (1/45 th of the body’s weight)

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THE BRAIN

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  1. THE BRAIN September 18, 2013

  2. Ways we Study the Brain 52-54 • CAT Scan • PET Scan • MRI • Functional MRI

  3. Lesions • Removal or destruction of some part of the brain. • Frontal Lobotomy

  4. What IS IT? • Jellylike mass of fat and protein • Weighs about 3 pounds (1/45th of the body’s weight) • 100 billion neurons make up the "gray matter” • Millions of dendrites and axons are the "white matter"

  5. Brain Structures 54-62 • Hindbrain • Midbrain • Forebrain • Cerebral Cortex (part of forebrain)

  6. “Older” Brain Structures-hindbrain • Brainstem • Oldest and innermost part • Where spinal cord enters brain (medulla) • Controls heartbeat, breathing, & blood pressure • Crossover point for nerves • Injury results in death

  7. Older Brain Structures, cont’d.-hindbrain • Cerebellum • Extends from back of brainstem (bottom rear of brain) • Means “little brain” • Involves coordination of voluntary movement • Coordinates fine muscle movements. • Habitual motor skills

  8. Older Brain Structures, cont’d.-hindbrain PONS • Located just above the medulla. • Connects hindbrain with midbrain and forebrain. • Involved in facial expressions.

  9. Midbrain If stimulated • Coordinates simple movements with sensory information. • Most important structure in Midbrain is the Reticular Formation: controls arousal and ability to focus our attention. If Destroyed

  10. MIDBRAIN Cont’d • Thalamus • Located at top of brainstem • Sensory “switchboard” of brain • Receives sensory signals from the spinal cord and sends them to other parts of the forebrain. • Every sense except smell.

  11. Midbrain cont’d • Limbic System • Border between older brain and two halves • Amygdala– aggression and fear • Hypothalamus – hunger, thirst, body temperature, sex • Hippocampus - memory

  12. Amygdala • Involved in how we process memory with emotions. • Emotions connected to survival: anger, fear, disgust The emotion of anger has not changed much throughout evolution.

  13. Hypothalamus • Maybe most important structure in the brain. Controls and regulates • Body temperature • Sexual Arousal • Hunger • Thirst • Endocrine System The most powerful structure in the brain.

  14. Rat with an Implanted Electrode in pleasure center of Hypothalamus

  15. Hippocampus • Involved in the processing and storage of new memories.

  16. In what brain region would brain DAMAGE BE MOST LIKELY TO … • … disrupt your ability to jump rope? • … disrupt your ability to hear sounds? • … leave you unable to move faster in a threatening situation? • … leave you unable to breathe?

  17. Forebrain 58-62 • What makes us human. • Largest part of the brain. • Made up of the Cerebral Cortex.

  18. CEREBRAL CORTEX • Layer of densely packed neurons “gray matter” and “glial cells”(glue), that support brain cells & cover the cerebral hemispheres. • Wrinkles are called fissures. • 80% of brain’s weight • Divided into four regions • Frontal lobes • Parietal lobes • Occipital lobes • Temporal lobes

  19. Frontal Lobes • Abstract thought and emotional control. • Contains Motor Cortex: sends signals to our body controlling muscle movements. • Contains Broca’s Area: responsible for controlling muscles that produce speech. • Damage to Broca’s Area is called Broca’s Aphasia: unable to make movements to talk.

  20. Parietal Lobes • Contain Sensory Cortex: receives incoming touch sensations from rest of the body. • Most of the Parietal Lobes are made up of Association Areas. Where would this girl feel the most pain from her sunburn?

  21. Occipital Lobes • Deals with vision. • Contains Visual Cortex: interprets messages from our eyes into images we can understand.

  22. Temporal Lobes • Process sound sensed by our ears. • NOT LATERALIZED. • Contains Wernike's Area: interprets written and spoken speech. • Wernike'sAphasia: unable to understand language: the syntax and grammar jumbled.

  23. CEREBRAL CORTEX, CONT’d.

  24. Association Areas • Any area not associated with receiving sensory information or coordinating muscle movements.

  25. Cerebral cortex, cont’d. • MOTOR FUNCTIONS • Sends messages out to body • How do scientists know what it does? • electrical stimulation of different parts • neural prosthetics

  26. Cerebral cortex, cont’d. • SENSORY FUNCTIONS • Receives information from skin’s senses • More sensitive body regions have greater area of sensory cortex devoted to them

  27. Motor and Sensory Cortexes

  28. LOCALIZATION OF BRAIN FUNCTION • How do scientists know the functions of different parts of the brain? • “Old” methods • phrenology • Brain damage case studies • Example: Case of Phineas Gage • Modern technology • EEG, CT, MRI, PET

  29. Accidents Phineas Gage Story • Personality changed after the accident. What does this tell us? • That different part of the brain control different aspects of who we are.

  30. Specialization and Integration in Language

  31. Hemispheres Divided into two hemispheres. • Contralateral control: right controls left and vice versa. In general, Left Hemisphere: logic and sequential tasks. Right Hemisphere: spatial and creative tasks.

  32. Brain Activity when Hearing, Seeing, and Speaking Words

  33. Brain Plasticity • The idea that the brain, when damaged, will attempt to find news ways to reroute messages. • Children’s brains are more plastic than adults.

  34. The Corpus Callosum Divides the 2 hemispheres.

  35. Split Brain Patients Those who suffer from epilepsy, have their corpus callosum severed partially.

  36. Testing the Divided Brain http://www.youtube.com/watch?v=ZMLzP1VCANo

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