A brain region that focuses on vision also receives signals that may help configure the operation of the brain, School of Medicine neuroscientists reported.
If the brain is thought of as an army, the new signals may give scientists a unique opportunity to trace how messages from the high command reach all the way down to individual soldiers in a particular platoon and affect their activities.
That’s because the brain region in question, called V1, has already been the focus of detailed studies at the level of individual brain cell interactions and how they encode and analyze data from the eyes.
“To really understand how a control signal works, you first have to know how the mechanism being controlled works, and we already have a fairly detailed feel for that in V1,” said Anthony I. Jack, Ph.D., a postdoctoral fellow and lead author of a study that appeared recently in the journal Neuron. “This provides us with a potential way of understanding a major puzzle: on a minute scale, how do control signals change how neurons process incoming information?”
Much of the human brain’s power derives from its ability to take one stimulus and process it in different ways to meet a variety of needs. Different parts of the brain have specialized abilities that can contribute in various ways to completion of different tasks. They just need to be told when to shift from one task to the next.
Scientists have long recognized V1 as the place where visual data first enters the cortex, the area responsible for many of the higher functions of human thought, analysis and decision-making. Aspects of the visual signal analyzed by V1 include the orientation of edges and lines.
“Edges form the boundaries of visual objects,” Jack said. “By encoding this information, the neurons in V1 provide the brain with the information that it uses to visually distinguish one object from another.”
The new results apparently show V1 responding to another, more abstract type of boundary: the divisions between mental tasks. The finding led to three years of follow-up studies, most devoted to showing that the signals coming into V1 were not a product of other, lower-level cognitive processes.
“What is exciting about this finding is the potential it presents for learning more about how control signals work at the neuronal level,” said Jack.
“At present, most ideas about how control signals work are based on theoretical models that seem plausible but have little detailed experimental support. That is problematic because nature often surprises us. It certainly did in this case.”