1. The Brain: Our Three Pound Universe
The Biological Basis of Behavior: Unit II

2. I. The Three Brains
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
Medulla
Pons
Cerebellum

3. B. Midbrain – small part of the brain above the pons that relays sensory information upward (vision & hearing).
Reticular 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
Thalamus
Hypothalamus
Cerebral cortex
Corpus callosum

4. Temporal (side, behind ears)
Brain Lobes (Each hemisphere of the cerebral cortex in divided into 4 lobes.)
Occipital (back)
Temporal (side, behind ears)
Wernicke’s Area
Broca’s Area
Parietal (top and rear)
Frontal (behind forehead)

7. Limbic System Inner edge of cerebrum Learning and memory Emotion
Hunger
Sex
aggression

8. Major parts of the brain and their functions
Forebrain
Thalamus-relay station for sensory stimulation
Relays messages from sense organs to cortex for interpretation
Hypothalamus-vital functions, regulates body temp., storage of nutrients, motivation, and emotion
Hunger, thirst, sexual behavior, caring for offspring, and aggression
Cerebrum- 70% of brain’s weight
Receives sensory info. and transmits motor info.
Cerebral cortex-wrinkled surface, part that “thinks”
Memory, language, emotions, complex motor functions, perception, etc.
Corpus callosum-connects two brain hemispheres of cerebral cortex

10. Major parts of the brain and their functions (contd.)
Midbrain
Reticular Activating System-stretches from hindbrain through midbrain, to lower part of forebrain
Coordinates basic movements with sensory info.
Attention
Sleep
Arousal (heart rates/blood pressure)
Alcohol lowers activity

12. Major parts of the brain and their functions (contd.)
Hindbrain
Medulla-heart rate and breathing, blood pressure, vital life functions
Pons-coordinates left & right sides of body, body movement, attention, sleep alertness, facial expressions
Cerebellum-balance and coordination, fine motor movements
Affected by alcohol (DUI test)

14. Brain Lobes (sensory & motor areas)
Occipital (back)
Primary visual area
Temporal (side, behind ears)
Hearing/auditory area
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
Broca’s Area
Language function/speech production
Damage-can comprehend written/spoken lang. but difficulty speaking
Damage to areas causes “aphasia”
Trouble understanding, producing language

15. Brain Lobes (condt.) Parietal (top and rear)
Skin senses (integrates sensory systems) touch, temperature, pressure
Frontal (behind forehead)
Motor skills, executive center
Problem solving, making plans & decisions, core of working memory, speech, learning, thinking

17. II. The Cerebral Hemispheres: Left and Right
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

18. 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.

20. III. Split Brain Patients Study
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.

21. Testing the Divided Brain

23. Accidents Phineas Gage Story 3.5 ft. iron rod
Personality changed after the accident.
What does this tell us?
That different parts of the brain control different aspects of who we are.
Damaged his frontal lobes

24. Neuroimaging Techniques
1. Computerized axial tomography (CAT Scan)
X-rays beam around the head (3D view)
Pinpoints injuries and brain deterioration

25. 2. Position Emission Topography (PET Scan)
Can see which areas of the brain are activated when performing tasks
A radioactive solution is injected into the body
Shows activity vs snapshot

26. 3. Magnetic Resonance Imaging (MRI)
Can see structures in detail, hard to see areas
Magnetic fields and radio waves
More powerful than CAT scan, “slice images”

28. 4.Electroencephalograph (EEG)
Measures electrical activity of brain using small electrodes pasted to you scalp
The rhymical patterns produced are “brain waves”

29. Chapter 3 Main Points (quiz review)
Divisions of the Nervous System
Parts/functions of neuron
Parts/functions of brain
Endocrine glands and hormones
Heredity/genes/chromosomes
Nature vs. Nurture