Our brains use "timestamps" to process the words we hear

A new study by a team of psychological and linguistic researchers suggests that our brains "timestamp" the order of incoming sounds, allowing us to correctly process the words
we hear.
The findings, published in the journal Nature Communications, provide new insights into
the complexity of neural function.

"To understand language, your brain needs to accurately interpret the features of speech and the order in which they are pronounced to correctly recognize what is being said," explains Laura Gwilliams, the paper's first author, who was a doctoral student at New York University at the time and is now a postdoc
at the University of California, San Francisco.
"We showed how the brain achieves this feat: different neural groups respond to
different sounds.
And, each sound has a time stamp that indicates how long
has elapsed since it entered the ear.
This allows the listener to know the order and characteristics of the sounds a person is speaking and thus correctly understand what words
the person is saying.
”

While the brain's role in processing individual sounds has been well studied, there's still a lot we don't know
about how we process the fast auditory sequences that make up speech.
A better understanding of brain dynamics could potentially address neurological disorders
that impair our ability to understand spoken language.

In the Nature Communications study, the scientists' goal is to understand how the brain processes the features and sequence of speech because they unfold so quickly
.
This is important because your brain needs to accurately interpret the identity of the sounds (such as L-E-M-O-N) and the order in which they are pronounced (such as 1-2-3-4-5) in order to correctly recognize the words being said (such as "lemon" instead of "melon"
).

To do this, they recorded the brain activity
of more than 20 English-speaking subjects while listening to two hours of audiobooks.
Specifically, the researchers linked
the subjects' brain activity to phonological properties that distinguish between different sounds, such as "m" and "n.
"

The researchers found that the brain uses buffers when processing language, thus maintaining a functioning expression
.
The timestamps
of the last three voices.
The findings also suggest that by transmitting information between neurons in the auditory cortex, the brain can process multiple sounds at the same time without confusing the characteristics of
each sound.

Gwilliams, who will return to NYU's Department of Psychology as an assistant professor in 2023, explains, "We found that every speech triggers a cascade of neuronal firings
in a different part of the auditory cortex.
This means that information about each sound in the phonetic word 'k-a-t' is passed between different neural groups in a predictable manner, which timestamps
the relative order of each sound.
”

Neural dynamics of phoneme sequences reveal position-invariant code for content and order