When we think of stuff, we often have mental representations (likely to be images) of whatever we are
thinking. We are capable of representing objects quite vividly in our minds without actually having
physical access to these objects. Intuitively, this tells us that thought processes interact quite a bit with
perceptual processes. In fact, it has been shown that similar brain regions are activated when we
imagine something than when we we actually perceive something. Furthermore, eye movements,
among other physical reactions, tend to resemble the perspective we would have (in the case of seeing).
For instance, people move their eyes downward when they are asked to imagine flying over their house
and describing it. This allows us to accomplish things when we are away from our place of interest and
allows us to imagine objects and places that we have never seen.
In 1971, Shepard and Metzler investigated how long it takes for people to identify if two objects
are the same object that has been rotated or if they are mirror images of one another. It was found that
reaction time increases linearly as the angle by which the object must be rotated increases in the case of
both objects being the same.
Intuitively, we would think that imagery involves brain regions associated with long-term
memory like the frontal, parietal, and temporal lobes. Instead, research has shown that increases in
activity were seen visual sensory areas in the case of recreating mental images of things.
Feedforward information processing: information goes from the sensory areas to the cognitive
areas. This stream of information is considered to be slower and more precise than feedback
information. Early sensory systems -> late sensory systems -> cognitive systems.
Feedback systems: information goes from cognitive areas to sensory areas. Cognitive systems
-> late sensory systems -> early sensory systems. This type of system change percepts before they are
processed in depth; for instance, our expectations and attention can inform our senses through a
feedback pathway to ignore certain parts of the information that is being received.
Feedback and feedforward systems interact with one another.
Brain regions that participate in vision have about a 2/3 overlap with brain regions that
participate in imagery. Data on this has been collected from fMRIs, patient data, and data from typical
participants. Researchers asked participants to either visualize objects or to perceive objects while their
brain activity recorded; they were then asked to judge something about the imagined/perceived object.
FMRI scans show that pretty much exactly the same brain regions of the frontal lobes are activated
during perception and imagery. In the parietal lobe, the same was observed. Note that these results were
done by taking the scans for both perception and imagery and