The Brain

Brain Rap

How do we see the brain?• EEG- electrodes on the brain that record

brain waves

• CT- shows structure of the brain

• PET- use dye to show brain activity

• MRI- shows tissue responses to pulses of magnetic energy

–fMRI- distinguishes activity levels of individual brain cells during various mental processes

EEG

CT Scan

PET Scan

MRI

fMRI

The 3 Layers of the Brain

• Brain Stem

• Limbic System

• Cerebral Cortex

3 Layers of the Brain

1. Brain Stem (R-Complex)

2. Limbic System

3. Cerebral Cortex

Carl Sagan video

Major Parts of the Brain Stem

• Medulla- controls automatic functions

• Pons- regulates sleep and dreams

• Reticular Formation- core of BS; monitors incoming sensory info and attention

• Thalamus- receives info and prioritizes and distributes it accordingly

• Cerebellum- handles coordination and balance

Anatomy of the Brain Stem

Mike the Headless Chicken

Major Elements of the Limbic SystemExists in all mammals- involved in memory, emotion and

caring for young• Hippocampus- establishes LTM• Amygdala- controls emotion; holds emotionally

charged LTM; center of fear and aggression (Waterboy got this wrong- don’t confuse with medulla!)

• Hypothalamus- body’s blood lab- monitors heart-rate, body temp, etc- important in _____ division of the PNS

Cerebral Cortex

• Primates ONLY: where all critical thought occurs

Lobes of the Cerebral Cortex1. Frontal- movement,

thinking1. Motor cortex

2. Parietal- touch, spatial relationships

1. Somatosensory cortex

3. Occipital- vision1. Visual cortex

4. Temporal- hearing, speech, some LTM1. Auditory cortex

Phineas Gage

Motor and Somatosensory Cortex• Homunculus:

represents the amount of space on the M and S cortexes dedicated for each location on the body.– Which part of the

human body has most representation on these cortexes? 2nd most? Least?

Association Cortex• Majority of cerebral cortex is used to associate

information from all cortical regions.– It will combine information from all over the brain,

interpret the sensations, plan, decide and prepare us to act.

Cerebral Dominance• Tendency of each hemisphere to control certain

functions

Left Brain Right Brain

• Regulates + emotion• Speech muscles• Movement sequence• Spontaneous

speaking/writing• Word and # memory• Understanding what you

hear or read

• Regulates – emotion• Response to simple

command• Shape and music

memory• Understanding spatial

relationships and visual images

• Recognition of faces

Hemispherical Communication• Corpus Callosum: bundle of nerve fibers that

transfers information between the hemispheres of the brain