Module 4.3 Flashcards
What was phrenology?
The process of relating skull anatomy to behaviors
Describe the CT scan.
method of visualizing a living brain by injecting dye into the blood and then passing x-rays through the head and recording them by detectors on the other side
What is the basis for the MRI?
Any atom with an odd-numbered atomic weight has an axis of rotation
Describe the EEG.
device that measures the brain’s electrical activity through electrodes on the scalp
What types of activity can the EEG measure?
It can record spontaneous brain activity or activity in response to a stimulus
How is the MEG different from the EEG?
The EEG measures electrical activity in the brain and the MEG measure magnetic activity in the brain.
How does the PET scan work?
Person receives an injection os a radioactive chemical. When a radioactive atom decays, it releases a positron that immediately collides with a nearby electron, emitting two gamma rays in opposite directions. The head is surrounded by gamma ray detectors and when two detectors record gamma rays at the same time, they identify a spot halfway between those detectors as the point of origin of the gamma rays. A computer uses this info to determine how many gamma rays are coming from each spot in the brain and therefore how much of the radioactive chemical is located in each area. The area showing the most radioactivity are the ones with the most blood and the most brain activity.
What is the physical basis for fMRI?
Hemoglobin; hemoglobin with oxygen reacts to a magnetic field differently from hemoglobin without oxygen. Because oxygen consumption increases when a brain area’s activity increases, researchers set the fMRI scanner to detect changes in the oxygen content of the blood as it responds to the amount of synaptic input reaching each brain area
What are the problems with inferring function from records of brain activity?
Interpreting results is complex. If you have more activity during a task you did the best in, the interpretation is that you activated more of your brain. If you do worse at an activity, the interpretation is that you need to activate more of your brain to deal with the more difficult task.
What did Paul Broca discover?
He discovered that a patient who had lost the ability to speak had damage to his left frontal cortex
What are four methods of deliberately inactivating brain activity in some location?
Lesions, the gene knockout approach, and transcranial magnetic stimulation
Compare the magnetic stimulation used to stimulate certain brain areas with that used to inactivate brain areas.
Intense magnetic stimulation inactivates and brief, mild stimulation stimulates it.
What is the problem with inferences about the function of brain areas based on localized stimulation?
Complex behaviors and experiences depends on many brain areas, not just one.
Why do scientists consider brain-to-body ratio rather than overall brain size when studying the relation of brain size to intelligence?
Because even though we consider ourselves to be the most intelligent animals, we do not have the largest brain-to-body ratio.
What are limitations of data correlating brain size and intelligence?
The correlation is barely about zero and this could mean either that they are unrelated or they were poorly measured.
