lecture #3 - brain structure and basic functions

cogsci

phineas gage

• 1848

• metal rod shot through his skull and penetrated his brain

• managed to function after the incident and had seemingly no problems in behaviour

phineas gage (pre-injury characteristics)

• well-balanced mind

• smart

• persistent in carrying out his plans

phineas gage (personality after the incident)

• disrupted balance between thinking and behaviour

• unpredictable

• no longer gage

• little respect for others

• used extreme profanity

what was intact/damaged for gage

• intact intelligence and emotions

• damaged logical thinking and impulse control

• impaired conscience

broadmann areas

• sampled core areas of the cortex under the microscope and saw that the cells looked different in different parts of the brain

functional specialization

• specific areas have specific functions

gyri

• brain has folds

• gyri increases brain surface area

• the more folds the greater the cognitive function

white matter

• myelinated axons

  • myelin sheath gives axons white colour

• necessary to transfer signals beyween neurons rapidly

gray matter

• unmyelinated axons

  • dark/grayish tissues

• gray cause of how it shows up when the brain is cut

hierarchy of the brain

1. cortex

2. limbic system

3. brain stem

limbic system

• fight or flight responses

• monitoring things outside of your awareness

cortex

• higher order cognition

• decision making

• object recognition

• consciousness

brain stem

• basic life support

roentgen

• first x-ray done on his wife

x-ray

• high energetic invisible rays of light

• bones are dense → absorb x-rays → appear light

• soft tissues are less dense → dont absorb x-ray → appear dark

why cant we see the brain on x-ray

• brain is encased in skull

• the dark continent

• cannot see past the skull

pheumoencephalography

• inject air into ventricles

• air bubble moves

• x-rays taken

CT scan

• take multiple 2D x-rays of body

• use program to combine slices into one 3D image