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Biological Bases of Behavior Chapter 3

Biological Bases of Behavior Chapter 3. What’s In This Chapter?. What does biology have to do with our behavior? What’s in a brain????? How does the brain tell the body what to do? How does the body let the brain know what it’s doing? Can your brain do things without the body?

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Biological Bases of Behavior Chapter 3

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  1. Biological Bases of Behavior Chapter 3

  2. What’s In This Chapter? • What does biology have to do with our behavior? • What’s in a brain????? • How does the brain tell the body what to do? • How does the body let the brain know what it’s doing? • Can your brain do things without the body? • Can your body do things without the brain knowing it?

  3. The Brain • Lesion • tissue destruction • a brain lesion is a naturally or experimentally caused

  4. Phineas Gagemusic video

  5. How we Investigate the Brain Electroencephalogram (EEG) • an amplified recording of the waves of electrical activity that sweep across the brain’s surface • these waves are measured by electrodes placed on the scalp

  6. How we Investigate the Brain • Electrical Stimulation of the Brain (ESB) • Mostly used with research on animals & some human brain surgery • Weak electrical currents sent into a brain structure to activate it • Transcranial magnetic stimulation (TMS) • New technique that temporarily enhance or depress activity in a specific area of the brain (about 2 centimeters in to the brain)

  7. CT (computed tomography) Scan • a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; also called CAT scan • Two-dimensional Sample image: Perfusion CT in a patient with stroke demonstrates the part of the brain with severely decreased blood flow (arrows).

  8. What are some common uses of the procedure? • Detection of bleeding, brain damage and skull fractures in patients with head injuries. • Detects a blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke. • Detection of most brain tumors. • Planning radiation therapy for cancer of the brain or other tissues. • Guiding the passage of a needle used to obtain a tissue sample (biopsy) from the brain.

  9. PET Scan PET (positron emission tomography) Scan • a visual display of brain activity (metabolic activity) that detects where a radioactive form of glucose goes while the brain performs a given task

  10. PET Scan Process • observe blood flow or metabolism in any part of the brain. • subject is injected with small quantity of radioactive glucose • Brain cells use glucose as fuel • shows levels of activity as a color-coded brain map • red indicates more active brain areas, • Blue/green: less active areas. • gray outer surface is MRI picture of the surface of the brain inner colored structure is cingulategyrus, part of the brain's emotional system

  11. MRI Scan MRI (magnetic resonance imaging) • technique uses magnetic fields and radio waves • produces computer-generated images • distinguish among different types of soft tissue • allows us to see structures within the brain • A brief pulse of radio waves disorients the brain’s atoms momentarily, when the atoms return to their normal spin, they release detectable signals.

  12. Healthy brain (left) Brain with schizophrenia (right) enlarged fluid filled brain region

  13. Examples of PET and MRI techniques Thalamus Cortex • These 2 images show subjects who received a painful injection of the chemical capsaicin into the upper arm. show increased blood flow (the PET scan shows the thalamus and primary somatosensory cortex after the injection. The gray areas of the images (the MRI) Using this method can identify the areas of the brain that are active during specific conditions. • could be used to study just about any other cognitive function.

  14. fMRI Scan • Functional magnetic resonance imaging (fMRI) • New MRI that monitors blood flow and oxygen consumption in the brain to identify areas of high activity • Higher resolution than a PET scan • Investgating the Anatomy of Sexual Arousal • p. 96 Discussion

  15. Brain Structures • The brain has three main parts: the forebrain, midbrain, and hindbrain. • The forebrain: cerebrum, thalamus, hypothalamus, & Limbic system • The midbrain: part of the brainstem • The hindbrain: cerebellum, pons and medulla (lower part of the brainstem)

  16. Lower-Level Brain Structures • Brainstem • the oldest part • central core of the brain • beginning where the spinal cord swells as it enters the skull • responsible for automatic survival functions • Medulla [muh-DUL-uh] • base of the brainstem • controls heartbeat and breathing

  17. The Brain

  18. Brain stem • "brain stem" is the part of your brain that was first to evolve in primitive human beings. • called a "reptilian brain" since it resembles almost the whole brain of a reptile. • source of all your instincts and feelings! • links your brain to your "spinal cord.“ • It is where all the incoming and outgoing "messages" come together and cross over.

  19. Controls sleeping, waking, and dreaming

  20. Reticular Formation (the panty hose) • a nerve network inside the brainstem that playsan important role in controlling arousal/sleep • Severe damage can induce a coma • Located in the brainstem • Thalamus [THAL-uh-muss] (411 operator) • the brain’s sensory switchboard, located on top of the brainstem; communication passes through • it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

  21. Cerebellum [sehr-uh-BELL-um] “Sarah the Southern Belle” • the “little brain” attached to the rear of the brainstem • it helps coordinate voluntary movement and balance • Important in walking, balance, or shaking hands

  22. The Limbic System

  23. Limbic System: a doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres • emotions such as fear and aggression • basic drives such food and sex • includes the hippocampus, amygdala, and hypothalamus. • Amygdala [ah-MIG-dah-la] • two almond-shaped neural clusters that are components of the limbic system and are linked to emotion (aggression/rageand fear)

  24. Hypothalamus: • neural structure lying below (hypo) the thalamus; directs several maintenance activities • eating • drinking • body temperature • helps govern the endocrine system via the pituitary gland • is linked to emotion • “pleasure center” or “reward center”

  25. The Limbic System • Electrode implanted in reward center • So reinforcing that the mouse pressed the pedal up to 7000x in one hour

  26. The Cerebral Cortex Cerebral Cortex • the intricate fabric of interconnected neural cells that covers the cerebral hemispheres • the body’s ultimate control and information processing center Glial Cells- glue cells • cells in the nervous system that support, nourish, and protect neurons

  27. Cerebral Cortex: Basic Subdivisions

  28. Structure of the Cerebral Cortex Frontal Lobes “behind your forehead” • involved in speaking and muscle movements and in making plans (initiative) and judgments (morality) Parietal Lobes “top and rear” • include the sensory cortex Occipital Lobes “back of head” • include the visual areas, which receive visual information from the opposite visual field Temporal Lobes “above the ears” • include the auditory areas

  29. Function of the Cerebral Cortex Motor Cortex • area at the rear of the frontal lobes that controls voluntary movements Sensory Cortex • area at the front of the parietal lobes that registers and processes body sensations

  30. The Cerebral Cortex

  31. The Cerebral Cortex • Functional MRI scan shows the visual cortex (occipital lobes) activated as the subject looks at faces

  32. Visual and Auditory Cortex Occipital Lobes Temporal Lobes

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

  34. The Cerebral Cortex & Language 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

  35. Specialization and Integration

  36. Specialization and Integration • Brain activity when hearing, seeing, and speaking words

  37. The Cerebral Cortex:Brain Reorganization • Plasticity • the brain’s capacity for modification, as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development • Children have a surplus of neurons • When one area is damaged, other areas may in time reorganize and take over some of its functions • “stem cell research”

  38. Corpus callosum Our Divided Brains Corpus Callosum • large band of neural fibers • connects the two brain hemispheres • carries messages between the hemispheres • Transfer more than a billion bits of info per sec.

  39. Our Divided Brains • The information highway from the eye to the brain • The opposite side of the brain’s hemisphere controls the opposite side of the body

  40. Hemispheric Specialization

  41. The Hemispheres of the Brain Clinical neurologists Gereon Fink of the University of Düsseldorf in Germany and John Marshall from the Radcliffe Infirmary in Oxford, pursued the idea that the difference between the two hemispheres lay in their style of working.

  42. “The left brain does the work that no one in their right mind would want to do.” -Amanda Barrow 1st period

  43. The Left Hemisphere (Verbal) • The left brain focuses on detail. • It is the natural home for all mental skills that need us to act in a series of discrete steps or fix on a particular fragment of what we perceive. • skills such as recognizing a friend's face in a crowd or "lining up" words to make a sentence.

  44. LEFT Hemisphere FUNCTIONS Speech Language Logic Writing

  45. RIGHT • Hemisphere • FUNCTIONS • concentrates on the broad, • background picture. • It has a panoramic focus.. • good at seeing general connections • best able to represent the relative position of objects in space • handles emotional and metaphorical aspects of speech.

  46. Right Hemisphere Functions Spatial Reasoning Art Music Emotions

  47. So, in a neat and complementary division of labor, one side of the brain thinks and sees in wide-angle while the other zooms in on the detail.

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