chapter 6, section 2. recording electrodes can be inserted into the brain to record activity. –...
TRANSCRIPT
Recording
• Electrodes can be inserted into the brain to record activity.– Can detect changes that occur when neurons fire.
• EEG: Attached to the scalp so many neurons can be monitored at once.
• Electrical activity of the brain rises and falls rhythmically.– Depends on wakefulness or sleepiness. – They are called brain raves.
Stimulation
• Electrodes can also set off the firing of neurons.
• Wilder Penfield– Stimulated the brains of patients during surgery to
determine functions various parts of the brain perform.
Lesions
• Cutting/destroying parts of the brain.– Sometimes scientists create these in animal
testing.
Accidents
• Learning from tragedy.• Phineas Gage, 1848– Respected railroad foreman, who executed good
judgment, and worked well with others.– Tamped a narrow hole with dynamite, and it
exploded. – Tamping iron weighed 13 lbs and 3 feet long.
Entered Gage’s head below the left eye, and exited through the top of the skull.
– Gage survived, but his personality changed greatly. Caused damaged to the frontal cortex.
• CT Scans– Moving ring passes X-ray
beams around and through a subject’s head. Radiation is absorbed, depending on brain tissue density.
– This produces a 3-D view of the brain.
• PET Scans– Injecting a radioactive
solution into the blood and measuring amount of radiation absorbed.• Active neurons absorb more
solution.
Images