Chapter 6- Body and Behavior. The Nervous System. Controls emotions, thinking, movements, and behavior Two Parts Central Nervous System (CNS)- brain and spinal cord Peripheral Nervous System (PNS)- smaller nerves that reach other parts of the body
Intensity of activity in each neuron depends on how many other neurons are acting on it
Each individual neuron is either
ON or OFF depending on
whether most of the neurons
acting on it are either exciting
Afferent neurons- relay messages from the sense organs to the brain
Efferent neurons- relay messages from brain to glands and muscles
Interneurons- carry impulses between neurons
When people are prone to grand mal seizures, separating the brain hemispheres will make them more severe
Side effects: seem normal
… but, if a man whose brain has been split holds a ball in his right hand, he will be able to say it is a ball, but in his left hand, he will not be able to say what it is. Information cannot cross to the speech center in the left hemisphere
to the temporal lobe, can
trigger memory sequences
radio was being played in
the operating room
** Pain relief without drugs
thoughts and ideas
A CT scan is essentially a computerized assembly of several x-ray images taken from a series of different angles. With a CT, the resolution is much better than conventional x-rays, and the detail that can be seen is much greater.
**Can pinpoint brain injuries and deterioration
PET measures the emission of positrons from the brain after a small amount of radioactive isotopes, or tracers, have been injected into the blood stream. A common example is a glucose-relative with embedded fluor-18. With this molecule, the activity of different regions of the brain can be measured. The result is a three-dimentional map with the brain activity represented by colors.
MRI is a noninvasive imaging technique that does not use x-rays. The process involves passing a strong magnetic field through the head. The magnetic field used is 30,000 + times that of the earth's magnetic field. It's effect on the body, however, is harmless and temporary. The MRI scanner can detect radiation from certain molecules, which are present in different concentrations in different tissues.