It has been said that the eyes are the front of the brain, especially since 80 percent of learning takes place via what we see. How does that happen and is it possible to utilize retinal imaging to diagnose age-related brain disorders? As always, researchers are studying these things and this is what was found at New York University.
Being able to store information for brief period of time, such as the location of a parked car or going to another room to retrieve an object, is known as working memory. This is the building block of higher cognitive processes and its failure leads to many neurological and psychiatric conditions, such as Alzheimer’s and schizophrenia. While the contents of working memory can be predicted from the patterns of brain activity, it wasn’t known what the patterns are coding.
Work in the lab of Clayton Curtis, professor of psychology and neural science at New York University, revealed the format of working memory in the brain. Curtis and study co-author Yuna Kwak, a doctoral student, theorized that human brains both discard task-irrelevant features and re-code task-relevant into formats that are efficient and distinct from the inputs. For example, when you see a phone number, you store the sounds of the numbers, not the image of the numbers.
To learn more about this, researchers measured the brain activity of study participants with functional magnetic resonance imaging (fMRI) while they performed visual working memory tasks, which consisted of a visual stimulus of either a tilted grating or a cloud of moving dots. After a short pause, the participants had to precisely indicate the exact angle of the grating tilt or the exact angle of the cloud of dots motion.
It was found that the patterns of neural activity were interchangeable. In other words, the pattern that predicted motion direction also predicted grating orientation. That lead to another question, namely, why were they interchangeable? Researchers guessed that only task-relevant characteristics of the stimuli were coded into memory in the form a line-like shape that was oriented to match the stimuli’s direction.
So, to test this, researchers projected the memory patterns onto a two-dimensional representation of visual space. This created a representation of the activity within the space of the monitor that the participants viewed and it allowed researchers to see how working memory was encoded. This method was able to separate how our brains selectively store relevant information while getting rid of information that is not relevant.
Part Two will deals with research that relates to the retina cognitive health.