How Does The Brain Sort Out What's Important?

A paper published in the journal Neuron, Volume 70, Issue 1, 14 April 2011, entitled "Strength of Response Suppression to Distracter Stimuli Determines Attentional-Filtering Performance in Primate Prefrontal Neurons" by Lennert, T. and Martinez-Trujillo, J., of McGill U. found that malfunctions of a filter neuron could be a cause of mental disorders.

Therese Lennert
McGill University
 

It has been assumed for some time that people with diseases like ADHD, Tourette syndrome, obsessive compulsive disorder, and schizophrenia suffer from anomalies in the brain’s prefrontal cortex.


Damage to this brain region is often associated with failure to focus on relevant things, loss of inhibitions, impulsivity, and various kinds of inappropriate behavior, but determining what makes the prefrontal cortex so essential to these aspects of behavior has remained elusive...


...Martinez-Trujillo believes the key to the brain clutter and impulsivity shown by individuals with dysfunctional prefrontal cortices lies in a malfunction of a specific type of brain cell. He has identified neurons in the dorsolateral...prefrontal cortex that selectively filter out important from unimportant visual information.


“Contrary to common beliefs, the brain has a limited processing capacity. It can only effectively process about one percent of the visual information that it takes in,” Martinez-Trujilo says. “This means that the neurons responsible for perceiving objects and programming actions must constantly compete with one another to access the important information."


“What we found when we looked at the behavior of the neurons in the prefrontal cortex, was that an animal’s ability to successfully accomplish a single action in the presence of visual clutter, was dictated by how well these units suppressed distracting information.”