Methods of Recording from the Brain Flashcards
What is the most basic kind of recording?
Intracellular or single-unit recording
How does the most basic kind of recording work?
an electrode is implanted in a particular neuron and the electrode records the change in the membrane potential.
What are the downsides to the most basic kind of recording?
Neurons are very small.
What is an alternative to the most basic kind of recording?
Extracellular recording - an electrode measures the membrane potentials from a population of cells from just outside those cells
What was phrenology?
This is when an experienced practitioner feels the bumps of your head and explains your neurological traits.
Who developed phrenology?
A german neuroanatomist Franz Joseph Gall who thought abilities and personality were located in certain parts of the brain and you could read it by feeling the bumps and contours of the brain.
What was phrenology used for?
As it grew, phrenology was used to justify the “inferiority” of certain races, classes, or sexes of human beings.
What is EEG? (think egg to remember this)
EEG stands for electroencephalogram and at first metal wires were inserted into the patient’s skull but modern EEG uses small metal discs called electrodes held together by a fabric cap and attached to the surface of the scalp with a little sticky jelly-like material.
What was the purpose of EEG?
the purpose of EEG is to record the electrical impulses created by large populations of neurons right through the skull. This appears on the recording equipment as large brain waves.
Who invented EEG?
In the 1920s, Hans Berger invented this to provide insights into mental processes.
What was EEG used for?
studying sleep, describing the different types of electrical waves that are present in the typical functioning brain and the differences in people without typical functioning brains.
What is a dipole, how is it made in the brain, and how well does EEG monitor these dipoles?
an area of negative charge next to an area of positive charge is a dipole The EEG electrodes on the scalp can capture these changes in charge very precisely and can show the changes in electrical activity in a certain field of neurons that take place over just a few milliseconds.
In the 1960s, what new information could scientists get from electrodes?
They could use computers to look at the electrical potential directly resulting from a particular stimulus or event shown to a subject, called ERP (event related potential)
What are the problems with EEG?
not really useful for pinpointing where in the brain certain activity is coming from, only useful for detecting or imaging activity from the outermost areas of the brain
Because of all the problems with EEG, what was a breakthrough?
magnetic resonance imaging or MRI
What is cognitive neuroscience?
neuroscience focused on the
cognitive or active thinking processes of living human beings
What is MRI?
medical imaging technique that uses a strong magnetic field to
produce detailed images of the inside of the body or other organism
How is MRI different from EEG?
MRI - the patient lies on a table inside a large, cylindrical machine called an MRI scanner, and the magnetic field is set up surrounding them
EEG - using a simple cap of electrodes
What is MRI used for?
examining parts of the body and detecting abnormalities and diagnosing injuries.
What happens to the patient during an MRI scan?
because the patient is put in a strong magnetic field, some of the hydrogen atoms in the body align.
List the 5 parts of an MRI scanner?
magnet, gradient coils, radio frequency coils, the patient table, and the bore
What can a basic MRI scan produce?
produce detailed images of the tissues inside the body and brain
How does an MRI work?
The strong magnetic field created by the MRI scanner causes the atoms in your body to align in the same direction. Radio waves are then sent from the MRI machine and move these atoms out of the original position. As the radio waves are turned off, the atoms return to their original position and send back radio signals.
There’s a specific way that processes the relaxation signals the atoms give off in an MRI that lets scientists see brain changes. What is it, what does it involve, and how does it work?
Specifically, red blood
cells carrying oxygen have different magnetic properties than red blood cells that are not carrying oxygen (deoxygenated). This means that when the magnetic field is applied (and when the RF pulse is applied), these forces act differently on oxygenated and deoxygenated blood,
