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Unformatted text preview: ease them into the bloodstream. 18
18 Mapping the Brain 19
19 Electroencephalogram 20
20 Positron Emission Tomography Active areas have increased blood flow
Radioactive isotopes (small amounts) are placed in the blood
Sensors detect radioactivity
Different tasks show distinct activity patterns
21 Magnetic Resonance Imaging Magnetic fields align certain ions and compounds
When field is removed, these molecules release energy as radio waves
Computer calculates tissue density from radio waves
Provides clear, 3D images 22
22 A Tour Through the Brain
The Brain Stem
The Hypothalamus and the Pituitary Gland
The Limbic System
The Cerebrum 23
23 The Human Brain The brain split in half from fronttoback Inside surface of right half of brain
Eyes on the left, near the word “hypothalamus” 24
24 The Brain Stem Brain Stem: At the top of the spinal cord, consisting of medulla and pons Medulla: Responsible for some automatic functions, such as breathing and heart rate
Pons: Involved in sleep, waking, and dreaming.
Reticular Activating System: A dense network of neurons found in the core of the brain stem; it arouses the cortex and screens incoming information.
25 The Cerebellum Cerebellum: Regulates movement and balance, and is involved in learning some simple responses. 26
26 Thalamus and Hypothalamus Thalamus: Hypothalamus: Relays sensory messages to the cerebral cortex.
Involved in emotions and drives vital to survival (e.g., fear, hunger, thirst, and reproduction); it regulates the autonomic nervous system. Pituitary Gland: Small endocrine gland at the base of the brain, which releases many hormones and regulates other endocrine glands.
27 The Limbic System Limbic System: Amygdala: A group of brain areas involved in emotional reactions and motivated behavior.
Involved in the arousal and regulation of emotion and the initial emotional response to sensory information. Hippocampus: Involved in the storage of new information in memory.
28 The Case of Phineas Gage Gage was a railroad construction foreman An 1848 explosion forced a steel tamping rod through his head Others said he was “…no longer Gage…” Lost his job, worked as a sideshow exhibit
29 The Two Hemispheres of the Brain
Split Brains: A House Divided
A Question of Dominance 30
30 Visual Pathways Each hemisphere receives information about the opposite side of the visual field. Objects to your left put images on right side of each retina; goes to right side of brain Half of optic nerve fibers cross at the optic chiasm
31 Split Brains: A House Divided Hemispheres of brain sometimes separated to treat severe epilepsy Split brain operation includes the optic chiasm
Optic nerve no longer crosses Visual information goes only to one hemisphere Different sides of brain see different information 32
32 Hemispherectomy Hemisphere of brain sometimes taken out to treat severe epilepsy “However, when a child has Rasmussen’s encephalitis, a rare, disease affecting one whole hemisphere of the brain, a hemispherectomy to remove all or almost all of one side of the brain may be performed. While it seems impossible that someone could function with only hal...
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- Fall '13