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THE BRAIN

THE BRAIN. Suppose we took your brain out of your body right before you died. We keep your brain alive by floating it in a tank of cerebral fluid while feeding it enriched blood and then transplanted the living brain into the body of a person with severe brain damage….

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THE BRAIN

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  1. THE BRAIN • Suppose we took your brain out of your body right before you died. We keep your brain alive by floating it in a tank of cerebral fluid while feeding it enriched blood and then transplanted the living brain into the body of a person with severe brain damage…. • Who’s personality, traits, habits, talents, would that “new” person have? • Would that be “YOU” in a new body or “Someone Else” in control of your brain?

  2. Tools of Discovery: How do we study the brain? Early Methods Modern Methods Modern methods record the brains electrical, metabolic, and magnetic signals using various techniques. Brain Lesion EEG CT Scan PET Scan MRI fMRI • Observation: Clinical Observations of patients revealed some brain-mind connections. • For example: Damage To • one side of brain caused paralysis on opposite side of body. • back of brain disrupts vision. • left front of brain causes speech difficulties.

  3. The Brain Techniques to Study the Brain A brain lesion experimentally destroys brain tissue to study animal behaviors after such destruction. Hubel (1990)

  4. Microelectrode Techniques • Very small electrodes inserted into individual neurons • Used to study activity of a single neuron • study the brain

  5. Macroelectrode Techniques • Used to get a picture of overall activity in the brain • An example is an EEG (Electroencephalogram), which uses electrodes placed on a person’s scalp to measure an amplified recording of the electrical waves sweeping across the brain’s surface.

  6. Structural Imaging • Computerized Axial Tomography (CAT-scan) • Uses X-rays to create a 3-dimensional image of the brain • CT scans can often show the size and locations of brain abnormalities caused by tumors, blood vessel defects, blood clots, strokes and other problems.

  7. Structural Imaging cont’d • Magnetic Resonance Imaging (MRI) • Uses a magnetic field and radio waves to produce computer-generated images • They distinguish among different types of brain tissue. • Image shows ventricular enlargement in a schizophrenic patient.

  8. CT Scan vs. MRI • CT may be less expensive than MRI. In addition, it is less sensitive to patient movement. • CT can be performed if you have an implanted medical device of any kind, unlike MRI. • MRI contrast materials used for image enhancement have very low incidence of side effects

  9. Functional ImagingShows the brain working (functioning in real time) • EEG imaging • 21 Sensors on the scalp record changes in electrical activity and feed them into a computer. The computer translates them into color and motion on a map of the brain displayed on a television monitor

  10. Functional ImagingShows the brain functioning in real time (movies or series of images) • Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) • Use radioactive glucose to determine location of greatest brain activity PET Scan of Alzheimer's Disease Brain PET Scan of Normal Brain

  11. Functional Imaging • Functional Magnetic Resonance Imaging (fMRI) • Shows function and structure by measuring movement of blood molecules within the brain.

  12. Medula Oblungata What do we have in common with these animals? OUR “OLD BRAIN”

  13. Older Brain Structures The Brainstemisthe oldest part of the brain, beginning where the spinal cord swells and enters the skull. It is responsible for automatic survival functions.

  14. Brain Stem The Medulla [muh-DUL-uh] is the base of the brainstem that controls heartbeat and breathing. Reticular Formationisa nerve network in the brainstem that plays an important role in controlling arousal.

  15. Brain Stem Pons and inside that the (Reticular Formation)isa nerve network in the brainstem that plays an important role in controlling arousal. • It is involved in motor control and sensory analysis... for example, information from the ear first enters the brain in the pons. It has parts that are important for the level of consciousness and for sleep. The Reticular Formation controls: • Attention • Cardiac Reflexes • Motor Functions • Regulates Awareness • Relays Nerve Signals to the Cerebral Cortex • Sleep

  16. Brain Stem The Thalamus [THAL-uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla.

  17. Cerebellum The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance.

  18. The Limbic System The Limbic Systemisa doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus.

  19. Amygdala The Amygdala [ah-MIG-dah-la] consists of two almond-shaped neural clusters linked to the emotions of fear and anger.

  20. Hypothalamus The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating, drinking, body temperature, and control of emotions. It helps govern the endocrine system via the pituitary gland.

  21. Reward Center Rats cross an electrified grid for self-stimulation when electrodes are placed in the reward (hypothalamus) center (top picture). When the limbic system is manipulated, a rat will navigate fields or climb up a tree (bottom picture). Sanjiv Talwar, SUNY Downstate

  22. The Cerebral Cortex The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. It is the body’s ultimate control and information processing center.

  23. Structure of the Cortex Each brain hemisphere is divided into four lobes that are separated by prominent fissures. These lobes are the frontal lobe (forehead), parietal lobe (top to rear head), occipital lobe (back head) and temporal lobe (side of head).

  24. The Cerebral Cortex • Frontal Lobes • involved in speaking and muscle movements and in making plans and judgments • Parietal Lobes • include the sensory cortex • Occipital Lobes • include the visual areas, which receive visual information from the opposite visual field • Temporal Lobes • include the auditory areas

  25. Acronym to help remember the 4 lobes of the brain: FTOP: Freud TorehisPants Off

  26. Functions of the Cortex The Motor Cortex is the area at the rear of the frontal lobes that control voluntary movements. The Sensory Cortex (parietal cortex) receives information from skin surface and sense organs.

  27. Visual Function The functional MRI scan shows the visual cortex is active as the subject looks at faces. Courtesy of V.P. Clark, K. Keill, J. Ma. Maisog, S. Courtney, L.G. Ungerleider, and J.V. Haxby, National Institute of Mental Health

  28. Auditory Function The functional MRI scan shows the auditory cortex is active in patients who hallucinate.

  29. Association Areas More intelligent animals have increased “uncommitted” or association areas of the cortex.

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

  31. The Cerebral Cortex • Aphasia • impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing 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 • zombie brains

  32. Specialization & Integration Brain activity when hearing, seeing, and speaking words

  33. Split Brain • Corpus Callosum • the large band of neural fibers connecting the two brain hemispheres and carrying messages between them. • ..\..\Myers Pwr Points 2013 edition\Myers AP - Unit 03B.ppt • Split Brain • a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.

  34. Right-Left Differences in the Intact Brain

  35. LEFT & RIGHT BRAIN

  36. Interactive Websites • 3D Brain • Split Brain Game

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