2. Franz Josef Gall (1758-1828)
• Phrenology
• Discredited when a
scientist, Pierre Flourens,
lesioned, or ablated,
animal brains
• Popularized the idea of
cerebral localization of
function
17. Electrical signals are transported down
an axon
• Dendrites: receive information
• inputs
• Axon: transmits electrical
signals
– Myelin: insulates the nerve cell
– Speeds up transmission
– Terminal buttons: release
transmitters
• Synapse: site of chemical
communication
19. Grey (or Gray) & White
Matter
Gray is the spelling more commonly seen in American use.
Grey is the spelling more commonly seen in British use (e.g. Earl Grey)
22. Action potentials
• Neurons specialize in
the transfer of
information within
the nervous system.
– Operated electrically
• Action potential
– Communicate
chemically
• Neurotransmitter
23. • Ions – electrically charged molecules
– Anions = negative
– Cations = positive
• A resting cell is more negative than its surrounding fluid
(extracellular fluid).
• The resting membrane potential is ~-70mV
– This is a negative polarity
27. Serotonin: Example neurotransmitter
• Serotonin (5-HT) is involved in mood
• Anti-depressants allow for more 5-HT (e.g. SSRI:
serotonin selective reuptake inhibitor)
28. Structural Imaging
• CAT (or CT): computerized axial
tomography
– Beam of X-rays (radiation)
at multiple angles
• MRI: magnetic resonance imaging
– Uses radio waves and measures cellular response in
a strong magnetic field
29. Functional Imaging
Active brain regions require more energy
provided by blood glucose.
• PET: positron emission tomography
– Radioactive substance to visualize blood flow
– OR to measure metabolic change (energy usage)
• fMRI: functional magnetic resonance imaging
– BOLD signal – Blood Oxygen Level Dependent
– Measures metabolic activity