I remember my elementary school teachers admonishing my classmates and me not to watch television while we did our homework. The reasons given were:
1) We ended up paying more attention to the program than our homework. Of course, there were those who did their homework during the commercial breaks.
2) Our homework ended up being sloppy and filled with errors.
3) Since our attention was divided, we didn’t learn anything, which is why we were given the homework in the first place.
Still, that doesn’t deter people from doing tasks like typing while watching a television program or reading while exercising on a stationary bike. How do the eye and brain collaborate so that a person can focus on primary task, such as typing, despite distractions? What is going on in the visual system that leads to memories being made.
Wouldn’t you know it, research is being done in these areas. One project is taking place at the University of Pennsylvania and another is being done at New York University (NYU).
Focus, Despite Distraction
Getting back to the example of doing homework while watching television, it is the “visual movement” neurons in the front of the brain that helps a person to stay focused on the homework.
Scientists at the University of Pennsylvania wanted to learn about the neural mechanism that helps the brain to decide whether to focus visual attention on a task that is rewarding or on an appealing distraction. They analyzed the neuron activity in animal models as they dealt with their attention being divided. What they found is a pattern of coordinated activity known as “beta bursts” in a collection of neurons in the lateral prefrontal cortex. These neurons are located in the front of the brain and are responsible for motivation and rewards and they seem to have a role in keeping the brain’s attention focused on the task by suppressing the influence of the distracting stimulus.
Researchers were eager to learn what leads to attention to certain stimuli, but other stimuli is suppressed. So, they recorded how the activity in the lateral prefrontal cortex shifts while completing a task, as the subject is being presented with visual distractions. Researchers found evidence that one kind of lateral prefrontal cortex neurons, known as visual-movement neurons, apply attention towards either the rewarding stimuli or the distracting one.
They also found that the visual-movement neurons in the lateral prefrontal cortex fired at together at the same frequency during periods when the subject was focusing on a task and ignoring visual distractions. These are the beta bursts and when they occurred in the moments before the visual stimuli were presented, the subjects were more likely to complete the task and ignore the stimuli. Conversely, when the beta bursts were weak or missing before the visual stimuli was presented, the subjects were more likely to pay attention to visual distraction.
This seem to indicate that the beta bursts begin in a network of visual-movement neurons and are “traffic directors” for the neurons that process different visual stimuli. It also shows that focusing on a task takes a lot of energy and it is a skill that can be improved.
How The Visual System Contributes To Memory
Our working memory allows a person to understand this sentence because each word is briefly stored in working memory until they are put together to form the meaning of the sentence. While the importance of working memory is known, what isn’t known are the neurological processes that sets this process in motion.
Enter research done at NYU to study how humans store the visual properties of memories in the occipital lobe, the location of the visual system. This study investigates how the neural codes store memories that change as individuals prepare responses based on these memories. It consisted of having subjects look where they remembered an object that disappeared after a few seconds.
Most theories about working memory state that the pattern of neural activity that stores a particular visual memory is the same as when it was first seen and encoded, whether it was a second or 10 seconds ago. These patterns store visual memories and establish a link between past stimulus and future memory guided response. Yet, recent studies show otherwise. Studies with animal show that the neural patterns are more dynamic than stable since the codes change over time.
So, to measure how the neural dynamics change, scientists developed methods to both measure the changing neural dynamics and make this information interpretable. They were able to encode a bump in neural activity when subjects were briefly presented with the visual target, in both the primary visual cortex and the high-level visual area. In the high-level visual area, the bump in activity remained at the target location throughout the memory delay. However, activity in the primary visual cortex evolves during a delay when a person is looking at the visual target and where they move their eyes after the delay. Scientists believe that this reflects the trajectory of the gaze shift that is being rehearsed in a person’s mind but is yet to be done.
These results show that the neural dynamics reflect the transformation of what we have seen into what we may do with the memory. So, if you want to remember the book you are reading or want to more fully enjoy the movie you are streaming, avoid multitasking.