A video game player manages to make ultra-fast decisions without compromising his or her performance. Far from reducing our ability to concentrate, video games can actually increase it. In the future, will they help us remobilize synaptic plasticity in adults and children alike? Undoubtedly, they are a powerful stimulant of attention, which is why my laboratory has developed a whole range of educational tablet games for math and reading, based on cognitive science principles.
Video games also have their dark side: they present well-known risks of social isolation, time loss, and addiction. Teachers who captivate their students, books that draw in their readers, and films and plays that transport their audiences and immerse them in real-life experiences probably provide equally powerful alerting signals that stimulate our brain plasticity.
The second attention system in the brain determines what we should attend to. This orienting system acts as a spotlight on the outside world. From the millions of stimuli that bombard us, it selects those to which we should allocate our mental resources, because they are urgent, dangerous, appealing. Because they have no interest for me. My experience is what I agree to attend to.
Only those items which I notice shape my mind. Selective attention operates in all sensory domains, even the most abstract. For example, we can pay attention to the sounds around us: dogs move their ears, but for us humans, only an internal pointer in our brain moves and tunes in to whatever we decide to focus on. At a noisy cocktail party, we are able to select one out of ten conversations based on voice and meaning. In vision, the orienting of attention is often more obvious: we generally move our head and eyes toward whatever attracts us.
By shifting our gaze, we bring the object of interest into our fovea, which is an area of very high sensitivity in the center of our retina. However, experiments show that even without moving our eyes, we can still pay attention to any place or any object, wherever it is, and amplify its features. We can even attend to one of several superimposed drawings, just like we attend to one of several simultaneous conversations.
And there is nothing stopping you from paying attention to the color of a painting, the shape of a curve, the speed of a runner, the style of a writer, or the technique of a painter. Any representation in our brains can become the focus of attention.
In all these cases, the effect is the same: the orienting of attention amplifies whatever lies in its spotlight. The neurons that encode the attended information increase their firing, while the noisy chattering of other neurons is squashed. The impact is twofold: attention makes the attended neurons more sensitive to the information that we consider relevant, but, above all, it increases their influence on the rest of the brain.
Downstream neural circuits echo the stimulus to which we lend our eyes, ears, or mind. Ultimately, vast expanses of cortex reorient to encode whatever information lies at the center of our attention.
Attention acts as an amplifier and a selective filter. For an object to come into the spotlight, thousands of others must remain in the shadows. To direct attention is to choose, filter, and select: this is why cognitive scientists speak of selective attention. This form of attention amplifies the signal which is selected, but it also dramatically reduces those that are deemed irrelevant. This is where the spotlight metaphor reaches its limits: to better light up a region of the cortex, the attentional spotlight of our brain also reduces the illumination of other regions.
The mechanism relies on interfering waves of electrical activity: to suppress a brain area, the brain swamps it with slow waves in the alpha frequency band between eight and twelve hertz , which inhibit a circuit by preventing it from developing coherent neural activity.
Paying attention, therefore, consists of suppressing the unwanted information—and in doing so, our brain runs the risk of becoming blind to what it chooses not to see.
Blind, really? In this classic experiment, you are asked to watch a short movie where basketball players, dressed in black and white, pass a ball back and forth.
Your task is to count, as precisely as you can, the number of passes of the white team. A piece of cake, you think—and indeed, 30 seconds later, you triumphantly give the right answer. What gorilla? We rewind the tape, and to your amazement, you discover that an actor in a full-body gorilla costume walked across the stage and even stopped in the middle to pound on his chest for several seconds.
It seems impossible to miss. Furthermore, experiments show that, at some point, your eyes looked right at the gorilla. Yet you did not see it. By doing so, scientists have also inadvertently started to take baby steps toward a better understanding of how body and mind—through automatic sensory experiences, physical movements, and higher-level consciousness—are deeply and inextricably intertwined.
For a long time, because attention seemed so intricately tied up with consciousness and other complex functions, scientists assumed that it was first and foremost a cortical phenomenon.
A major departure from that line of thinking came in , when Francis Crick, known for his work on the structure of DNA, proposed that the attentional searchlight was controlled by a region deep in the brain called the thalamus, parts of which receive input from sensory domains and feed information to the cortex. He developed a theory in which the sensory thalamus acted not just as a relay station, but also as a gatekeeper—not just a bridge, but a sieve—stanching some of the flow of data to establish a certain level of focus.
Read: The attention machine. But decades passed, and attempts to identify an actual mechanism proved less than fruitful—not least because of how enormously difficult it is to establish methods for studying attention in lab animals.
He was drawn to a thin layer of inhibitory neurons called the thalamic reticular nucleus TRN , which wraps around the rest of the thalamus like a shell. By the time Halassa was a postdoctoral researcher, he had already found a coarse level of gating in that brain area: The TRN seemed to let sensory inputs through when an animal was awake and attentive to something in its environment, but it suppressed them when the animal was asleep.
In the study, the researchers used mice trained to run as directed by flashing lights and sweeping audio tones. They then simultaneously presented the animals with conflicting commands from the lights and tones, but also cued them about which signal to disregard. As expected, the prefrontal cortex, which issues high-level commands to other parts of the brain, was crucial. But the team also observed that if a trial required the mice to attend to vision, turning on neurons in the visual TRN interfered with their performance.
And when those neurons were silenced, the mice had more difficulty paying attention to sound. The researchers also found that the communication was initiated by the IFJ and the activity was staggered by 20 milliseconds — about the amount of time it would take for neurons to electrically convey information from the IFJ to either the FFA or PPA. The researchers believe that the IFJ holds onto the idea of the object that the brain is looking for and directs the correct part of the brain to look for it.
They are also investigating whether it might be possible to train people to better focus their attention by controlling the brain interactions involved in this process.
Home News How the brain pays attention. Study finds a striking difference between neurons of humans and other mammals. A connectome for cognition.
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