4.3 Research Methods Flashcards
In 1861, Paul Broca found that a patient who had lost the ability to speak had damage in part of his left frontal cortex. Additional patients with loss of speech also showed damaged in and around that area, now known as ____ ____.
Broca’s area
Examine the effects of brain ____. After damage or temporary inactivation, what aspects of behaviour are impaired?
damage
Examine the effects of ____ a brain area. Ideally, if damaging some area impairs behaviour, stimulating that area should enhance the behaviour.
stimulating
____ brain activity during behaviour. We might record changes in brain activity during fighting, sleeping, finding food, solving a problem, or any other behaviour.
Record
____ brain anatomy with behaviour. Do people with some unusual behaviour also have unusual brains? If so, in what way?
Correlate
An ____ is a removal of a brain area, generally with a surgical knife.
ablation
Surgical removal is difficult for tiny structures far below the surface of the brain. In that case, researchers make a ____, meaning damage.
lesion
To damage structure in the interior of the brain, researchers use ____ instrument, a device for the precise placement of electrons in the brain.
stereotaxic
____ ____ ____, the application of intense magnetic field to a portion of the scalp, temporary inactivates neurons below the magnet. This procedure enables researchers to study a given individual’s behaviour with the brain area active, then inactive, and then active again.
Transcranial magnetic stimulation
Researchers can insert electrodes to stimulate brain areas in laboratory animals. A new technique, ____, enables research to turn on activity in targeted neurons by a device that shines a laser light within the brain.
optogenetics
Where as intense transcranial magnetic stimulation inactivates the underlying brain area, a brief, mild application ____ it.
stimulates
A limitation of any stimulation study is that complex behaviours and experiences depend on a temporal pattern of activity across many brain areas, not just a general increase of activity in one, so ____ stimulation produces ____ responses.
artificial
Studies of human brains almost always use ____ methods – that is, methods that record from outside the skull without inserting anything.
non-invasive
A device called the ____ (EEG) records electrical activity of the brain through electrodes attached to the scalp.
electroencephalograph
The EEG can record spontaneous brain activity or activity in response to a stimulus, in which case we call the results ____ ____ or ____ ____.
evoked potentials or evoked responses
A ____ (MEG) is similar, but instead of measuring electrical activity, it measures the faint magnetic fields generated by brain activity.
magnetoencephalograph
Like an EEG, an MEG recording identifies the approximate location of activity to within about a ____.
centimetre
Another method, ____ ____ (PET), provides a high-resolution image of activity in a living brain by recording the emission of radioactivity from injected chemicals.
positron-emission tomography
PET scans have been replaced by ____ ____ ____ ____ (fMRI), which is less expensive and less risky.
functional magnetic resonance imaging
Standard MRI scans record the energy released by ____ molecules after the removal of a magnetic field.
water
And fMRI is a modified version of MRI based on ____ (the blood protein that binds oxygen) instead of water. ____ with oxygen reacts to a magnetic field differently than ____ without oxygen.
haemoglobin
When a brain area becomes more active, two relevant changes occurred: First, blood vessels ____ to allow more blood flow into the area. Second, as the brain area uses ____, the percentage of haemoglobin without oxygen increases.
dilate : oxygen
A given brain area may have many ____, and we have to be cautious about equating one area with one function.
functions
If we think we know what a given fMRI pattern means, we should be able to use that pattern to ____ what someone is doing or thinking.
identify
Gall in the 1800s assumed that bulges and depressions on a skull corresponded to the brain areas below them. This understanding is known as ____.
phrenology
A ____ ____ ____, better known as a CT or CAT scan is where a physician injects dye into the blood (to increase contrast in the image) and then places the person’s head into a CT scanner.
computerised axial tomography
____ are then passed through the head and recorded by detectors on the opposite side. CT scans help to detect tumours and other structural abnormalities.
X-rays
Another method is ____ ____ ____ (MRI), based on the fact that any atom with an odd numbered atomic weight, such as hydrogen, has an axis of rotation.
magnetic resonance imaging
Research using modern methods to measure brain size suggests a moderate positive relationship between brain size and ____, although many puzzles and uncertainties remain.
intelligence
Men and women are equal in IQ scores, despite men having ____ brains.
larger
