The Brain Our Three Pound Universe The Biological
The Brain: Our Three Pound Universe The Biological Basis of Behavior: Unit II
I. The Three Brains n A. Hindbrain – part of the brain at the rear base of the skull, involved in the basic processes of life ¨ 1. Oldest part ¨ 2. Responsible for automatic and survival functions ¨ 3. Three parts n n n Medulla Pons Cerebellum
n B. Midbrain – small part of the brain above the pons that relays sensory information upward (vision & hearing). ¨ Reticular n activating system C. Forebrain – the most highly developed part of the brain responsible for the most complex aspects of behavior and mental life. ¨ 1. Covers the brain’s central core ¨ 2. 4 parts n n Thalamus Hypothalamus Limbic System Cerebrum
Brain Lobes (Each hemisphere of the brain is divided into 4 lobes. ) 1. 2. Occipital (back) Temporal (side, behind ears) n n 3. 4. Wernicke’s Area Broca’s Area Parietal (top and rear) Frontal (behind forehead)
Major parts of the brain and their functions n Forebrain ¨ ¨ ¨ Thalamus “inner chamber”-relay station for sensory stimulation n Relays messages from sense organs for interpretation Hypothalamus “under”-vital functions, regulates body temp. , storage of nutrients, motivation, and emotion n Hunger, thirst, sexual behavior, caring for offspring, and aggression Cerebrum “brain”- 70% of brain’s weight n Receives sensory info. and transmits motor info. n Cerebral cortex “bark”-wrinkled surface, part that “thinks” ¨ Memory, language, emotions, complex motor functions, perception, etc. n Corpus callosum-connects two brain hemispheres of cerebral cortex
Limbic System n Inner fringe of cerebrum ¨ Learning and memory ¨ Emotion ¨ Hunger ¨ Sex ¨ Aggression ¨ *Evolutionary Psy*
Major parts of the brain and their functions (contd. ) n Midbrain ¨ Reticular Activating System-stretches from hindbrain through midbrain, to lower part of forebrain ¨ Coordinates basic movements with sensory info. n n Attention Sleep Arousal (heart rates/blood pressure) Alcohol lowers activity
Major parts of the brain and their functions (contd. ) n Hindbrain ¨ ¨ ¨ Medulla-heart rate and breathing, blood pressure, vital life functions Pons-coordinates left & right sides of body, regulates body movement, attention, sleep alertness, & facial expressions Cerebellum-balance and coordination, fine motor movements n Affected by alcohol (DUI test)
Brain Lobes (sensory & motor areas) n n Occipital (back) ¨ Primary visual area Temporal (side, behind ears) ¨ Hearing/auditory area n Wernicke’s Area ¨ Language function, puts together sounds & sights ¨ Damage-difficulty understanding written/spoken lang. Can speak quickly & easily but speech often makes no sense n Broca’s Area ¨ Language function/speech production ¨ Damage-can comprehend written/spoken lang. but difficulty speaking n Damage to areas causes “aphasia” ¨ Trouble understanding, producing language
Brain Lobes (condt. ) n n Parietal (top and rear) ¨ Skin senses (integrates sensory systems) touch, temperature, pressure Frontal (behind forehead) ¨ Motor skills & problem solving n Making plans & decisions, core of working memory, speech, learning, thinking
II. The Cerebral Hemispheres: Left and Right n n A. corpus callosum – a connection of nerve bundles that carry messages between our two brain hemispheres B. each hemisphere controls the opposite side of the body
n n n C. laterization – specialization of the two cerebral hemispheres (L&R) for particular functions 70% of lefties are left hemisphere dominant for language Left Hem. -usually handles verbal processing, language, speech, reading, & writing Right Hem. -usually handles nonverbal processing, spatial, musical, and visual Primary sensory & motor areas are symmetrical.
III. Split Brain Patients Study n n n Split Brain Patients- those who due to severe epilepsy, have their corpus callosum cut. Epilepsy-seizures due to neuron misfires that can spread from hem. to hem. Roger Sperry-won Nobel Prize in physiology/medicine.
Testing the Divided Brain
Accidents Phineas Gage Story n 3. 5 ft. iron rod n Personality changed after the accident. What does this tell us? n That different parts of the brain control different aspects of who we are. ¨ Damaged his frontal lobes
n Neuroimaging Techniques ¨ 1. Computerized axial tomography (CAT Scan) n n X-rays beam around the head (3 D view) Pinpoints injuries and brain deterioration
¨ 2. Position Emission Topography (PET Scan) n n n Can see which areas of the brain are activated when performing tasks A radioactive solution is injected into the body Shows activity vs snapshot
¨ 3. Magnetic Resonance Imaging (MRI) Can see structures in detail, hard to see areas n Magnetic fields and radio waves n More powerful than CAT scan, “slice images” n
4. Electroencephalograph (EEG) n Measures electrical activity of brain using small electrodes pasted to your scalp n Rhymic patterns produced are “brain waves”
Chapter 3 Main Points (exam review) Divisions of the Nervous System n Parts/functions of neuron n Parts/functions of brain n Endocrine glands and hormones n Heredity/genes/chromosomes n Nature vs. Nurture n
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