Changing how people direct their attention – and the associated brain patterns – could be key to some promising behavioral therapies to help everyone from smokers to patients with attention deficit hyperactivity disorder (ADHD). A symposium Tuesday morning at CNS 2013 set out to integrate the current state of research on the neural networks involved in attention with research in perception, memory, and other aspects of cognitive science.
Behavioral studies are transitioning to multifaceted investigations that take into account disciplines such as genetics and brain anatomy, said Michael Posner of the University of Oregon. He pointed to research identifying a gene on Chromosome 11 that plays a role in ADHD, but only if the gene bearer’s parents aren’t up to snuff with their child-rearing skills.
Posner also called the results of recent brain imaging research from his laboratory “a harbinger for anatomically organized efforts to develop [behavioral] training.” The study revealed that mindful meditation in smokers actually changed the architecture of the brain’s white matter. What’s more, test subjects cut back on the number of cigarettes they went through by about 70 percent. Participants didn’t necessarily want to quit, so it was “actually surprising to the people who smoked when they found out they weren’t smoking so much,” Posner said.
Kia Nobre of the University of Oxford also has applied modern methods to the study of attention. But in her lab’s case, she and her colleagues study attention in people as it relates to memory, and specifically long-term memory.
When test subjects were asked to identify an object in the same set of pictures over and over, fMRI scans of their brains showed that the tasks energized the frontal parietal lobe, an area of the brain critical to long-term memory. And this part of the brain was actually much more involved than parts associated with vision. To take it a step further, Nobre and her colleagues found that subjects performed significantly better on orientation tasks when they engaged their long-term memory as opposed to their visual centers.
In a nod to the breadth of methodologies employed to understand attention, the symposium’s other two speakers talked about their research on brain waves. Sabine Kastner of Princeton University has uncovered the importance of the thalamus in keeping neurons in sync – a condition critical for attention. If the waves fall off the beat, it can cripple attention.
In studies on macaques, Kastner and her team looked at wave functions while the monkeys performed a series of tasks that required their attention. They found that a part of the brain at the back of the thalamus called the pulvinar plays a critical role synchronizing the waves of activity, working as a sort of “clock” in the attention network.
Earl Miller of MIT and his team are also interested in the synchronicity of brain waves. By implanting 60 electrodes into the brains of monkeys, they recently established that brain waves involved in top-down attention were beta (low-frequency) waves. In the more automatic, bottom-up attention – the kind you might instinctively pay to the source of a loud noise – gamma, or high-frequency, waves rule. “So it’s as if the brain is using two different spots on the FM dial for two different forms of attention,” Miller explained.
Top-down attention plays a crucial role in allowing us to hold more than one thought in our brains at the same time. Even humans can hold onto at most four or five thoughts at once, Miller pointed out. To keep track of multiple thoughts, groups of neurons oscillate out of sync with each other. As Kastner demonstrated in her talk, this slippage can often result losing the attentive state – a big reason, Miller says, why holding multiple ideas in our minds is so tough.