THE ESSENTIAL
- Responses to distraction stimuli are suddenly suppressed beyond the sensory cortex.
- It is the prefrontal cortex that orchestrates this process of filtering stimuli to let pass only those which are essential to perform the task at hand.
- This discovery may help better target and understand the treatment of neuropsychiatric diseases such as attention deficit hyperactivity disorder and schizophrenia.
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To stay focused, our brains have the ability to block many distracting stimuli. Psychologists from the University of California (United States) have discovered for the first time that it is in our cortex that our brain filters stimuli to sort out those that are important for us to perform the task. accomplish and those who are there to distract us. The researchers published their results in the Journal of Neuroscience.
The prefrontal cortex
By conducting experiments on mice, the researchers were able to locate the exact location in the brain where distracting stimuli are blocked. To do this, they trained mice in a sensory detection task using target and distractor stimuli. The mice learned to respond to rapid stimuli and to ignore identical stimuli in the opposite distraction field. The team used a new imaging technique, which allows high spatio-temporal resolution with a cortex-wide field of vision, to find where distracting stimuli are blocked.
The results of this study made it possible to identify the cortex as being the place of our brain filtering the various stimuli. “We observed responses to target stimuli in several sensory and motor cortical regions, notes Edward Zagha, who led the study. In contrast, responses to distraction stimuli were abruptly suppressed beyond the sensory cortex.. (…) When someone is highly distracted, their cortex does not sufficiently deploy the intentional signals necessary to prevent distractor stimuli from propagating in working memory or triggering a behavioral response. These processes – the ‘gatekeepers’ of sensory signals – allow only the signals that are relevant to the task being carried to pass through. We believe that this process is orchestrated by the prefrontal cortex.”
Treat neuropsychiatric diseases
The next step for researchers is to understand, in neural activity, how distracting stimuli are blocked. “The spatial accuracy of our results gives us the certainty that we know where to look in future studies to reveal how distraction stimuli are blocked, allowing us to stay focused on the task at hand. This major challenge consists in recording neural activity at high spatial and temporal resolution in animals while they perform targeted tasks., specifies the researcher. The second major challenge is to use the right calculation methods to analyze this neural activity.”
This discovery opens up treatment prospects for diseases linked to attention disorders. “Our discovery may have important implications for understanding and treating neuropsychiatric conditions such as attention deficit hyperactivity disorder and schizophreniasays Edward Zagha. By studying the mechanisms underlying the blocking of distracting stimuli, we may be able to unravel the neural circuits underlying attention and impulse control. The better we understand these circuits, the better we can design rational and targeted treatments to improve impulsivity in these disorders.”
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