We don’t realise it, but with every glance we make our eyes take in a staggering amount of visual information. Whether we are crossing a street, watching a football game or strolling through the park, we are met with rich landscapes of visual detail. Still, we have no trouble focusing on what interests us and ignoring the rest. How our brains filter this constant torrent of input is a mystery, but new research from McGill University in Canada has pinpointed neurons involved.
The study, recently published in the journal Neuron by neuroscientists Therese Lennert and Julio Martinez-Trujillo, focused on part of a region in the brain called the prefrontal cortex. This region enables us to plan actions and make decisions, and is important in focusing attention.
To explore how neurons in this particular area, known as the dorsolateral prefrontal cortex, respond to distracting information, the researchers monitored neural activity while animal subjects observed two sets of moving dots: the target of interest and the distracter. They found that when distraction was minimal, the neurons suppressed their response to it. Yet, as distraction increased, the neurons responded more and the subjects had greater difficulty focusing on the target.
Lennert explained, “It’s well-established that this brain area is important in attention. What we add is that the suppressive response of that region correlates with behaviour.” Essentially, the subjects’ ability to pay attention rested on how well their neurons filtered out the distractions.
Overall, this work brings insight into exactly why this region of the prefrontal cortex is vital for making sense of our visual world. As a further step, additional study of these neurons could help determine what goes wrong in conditions like attention deficit hyperactivity disorder, where the brain cannot properly filter out unimportant information.
Read the original paper.
Posted on Wednesday, 20th July, 2011