When inferring the presence of a specific cognitive process from observed brain activation a kind of reasoning is applied that is called reverse inference. As a consequence, reverse inference is assumed as intrinsically weak by many and its validity has been increasingly regarded as limited.
Q. What is regrouping across zeros?
Regrouping is taking some value from one place and giving it to another place that needs more. Now, let’s give it a twist.
Table of Contents
- Q. What is regrouping across zeros?
- Q. How did Donders subtraction method work?
- Q. What is cognitive subtraction?
- Q. Why is the subtraction method in brain imaging important?
- Q. What is forward and reverse inference?
- Q. What is a forward inference?
- Q. Why is reverse inference problematic?
- Q. What is Functional MRI of the brain?
Q. How did Donders subtraction method work?
Donders calculated the time required for each stage by using a subtraction technique: Perception and motor time = the time required for the simple task. He demonstrated a simple principle: The time it takes to perform a task depends on the number and types of mental stages involved.
Q. What is cognitive subtraction?
Definition. In functional neuroimaging studies, cognitive subtraction refers to an aspect of experimental design involving the comparison of two conditions or brain states that are presumed to differ in only one discrete feature (the independent variable).
Q. Why is the subtraction method in brain imaging important?
The idea behind this was that the same brain regions, the same visual processing is involved in passively viewing things. But, the experimental task involved word recognition visually, and therefore, subtraction could be used to tease out the brain regions involved.
Q. What is forward and reverse inference?
Whereas the reverse inference is a (probabil- istic) assignment of a cognitive process to activation of a specific brain region [4], forward inference refers to the use of qualitatively different patterns of activity over the brain to distinguish between competing cognitive theories.
Q. What is a forward inference?
Forward inference is a special case with two theories and the observed results being either the same pattern of brain activity across two experimental tasks or different patterns of brain activity.
Q. Why is reverse inference problematic?
Inferring what someone is thinking or feeling by observing brain activity. Given that certain neurons or voxels show a change in activity, occurs what psychological task is being performed? Reverse inference is a problem because neurons (circuits and networks) are usually multipurpose (also called domain-general).
Q. What is Functional MRI of the brain?
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases.
