1. Module 4: The Brain

2. Why study the brain? Every good thing happens in the brain
Thoughts, memories, dreams, pleasure, love, decisions, motivation
Everything that we want to avoid happens in the brain
Anger, nightmares, physical pain, emotional pain, anxiety, depression
“The mind is what the brain does”
So is an emotion
So is a behavior

3. How do we study the brain?
Autopsies
Clinical observations
EEG
Neuroimaging

4. Electroencephalogram (EEG)
an amplified recording of the waves of electrical activity
these waves are measured by electrodes placed on the scalp

5. Neuroimaging PET (positron emission tomography) Scan
Radioactive form of sugar is given
Sugar goes to the region of the brain that is active
MRI (magnetic resonance imaging)
uses magnetic fields and radio waves
Generates images that distinguish among different types of soft tissue
Functional MRI
Reveals blood flow, therefore brain activity
Compares successive MRI scans while the patient is performing a task

6. MRI
Schizophrenia

7. fMRI
The visual cortex is activated as the subject looks at faces

8. The Older and Newer Brain Structures

9. Older Brain Structures: The brainstem
Relays sensory input except smell
Filters information
Controls alertness
Brainstem is the medulla and the pons
Brainstem is the crossover point – nerves from each side of the body connects to the opposite side of the brain.
Pons
Coordinates movements
Heartbeat and breathing
Brainstem

10. Cerebellum the “little brain” at the rear of the brainstem
Non-verbal learning: judge time, modulate emotions, discriminate using senses
helps coordinate voluntary movement and balance
Baseball sized
Clearly works with the pons
Damage results in difficulty walking, keeping balance, shaking hands, etc. jerky-exaggerated movement

11. The Limbic System Hippocampus: processes memory
Amygdala: Influences aggression and fear
Perception of these emotions
Processing of emotional memories
Hypothalamus: Monitors the blood chemistry and the pituitary gland
Influences feelings of hunger, thirst, body temperature and sexual arousal
Houses the pleasure or reward centers
Limbic system resides around the older brain parts and the cerebral hemispheres
If hippocampus is damaged, individuals become unable to process new memories
Amygdala has two bean sized structures
It is likely that addictive behaviors are partly due to damage or malfunction of the limbic system
Note that pleasure is associated with neurotransmitters endorphines and dopamine

12. The Cerebral Cortex: our resource for adaptability
Cerebral Hemispheres
Corpus Callosum
the intricate fabric of interconnected neural cells that covers the cerebral hemispheres
the body’s ultimate control and information processing center
Corpus callosum maintains the information flow between the two hemispheres of the brain

13. The Structure of the Cortex
Frontal Lobes: Thinking, planning, movement
Parietal Lobes: body sensation
Occipital Lobes: Vision
Temporal Lobes: Hearing, language
Lobes are separated by prominent fissures (folds)
80% of the weight of the brain is the cortex
It has 300 trillion synaptic connections

14. The Motor Functions
Parts of the body requiring precise control takes up more room on the motor cortex

15. Sensory functions
Higher sensitivity in an area is associated with larger area on the sensory cortex
Lips in humans
Whiskers in rats
Stimulation in the sensory cortex produces feelings
Stimulation of the auditory cortex  hearing sounds (hallucinations)

16. Association areas of the cortex: 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

17. Language functions: mostly on the left hemisphere
Some individuals have discrepant abilities to read-write-speak-sing.
READING
Register in visual area
Transform words into auditory code
Auditory code received and understood
Motor area produces the word

18. Brain Plasticity The brain’s capacity for modification
Brain reorganizes itself following damage (especially in children)
Brain reorganizes itself through intense learning experiences
London cab drivers

19. Our divided brain
Hemispheres control and receive information from the opposite sides of the body
Hemispheric Specialization
Left hemisphere: language, logic, and complex motor behavior
Right hemisphere: non-linguistic functions including recognition of faces, places, and sounds (music)
The hemispheric specializations are evident from studies of
Damage to one hemisphere (I.e. Broca’s area)
Split-brain subjects