It’s remarkable how adaptable the human brain is especially in these extremely busy, crowded and most of all noise times. Focus is key, of course, and recently researchers have shown for instance how the brain hones in at one speaker at a time when subjected to multiple external stimuli, like other people jabbering around at a cocktail party.
There’s no easy way of blocking sound. You can’t just close your ears, like you can with your eyes, however luckily our brains have specially developed filters that only process information related to sound that is deemed important, and that’s very fortunate since otherwise we all would have gone insane.
At a sensory level, all sounds are picked up by the brain, and this is very important to know, but how does the brain prioritize which sounds need to be encoded? Senior author Dr. Charles Schroeder, of Columbia University’s Department of Psychiatry, along with colleagues directly recorded brain patterns from in surgical epilepsy patients, who were listening to natural spoken sentences. In the auditory cortex – the part of the brain responsible for processing sound, like speech – both attended and ignored speech was reflected in brain signals. The attended speech, however, had a much greater signal amplitude.
However, in “higher-order processing” regions of the brain – responsible for language processing and attention control – things were a lot different. Here attended speech was clear, while that of ignored speech was not detectable.
“While confirming this, we also provide the first clear evidence that there may be brain locations in which there is exclusive representation of an attended speech segment, with ignored conversations apparently filtered out,” the authors write in their paper published in the journal Neuron.
The findings could help scientists develop solutions for people suffering from deficits such as those associated with attention deficit hyperactivity disorder, autism, and aging.
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