New research on how the brain makes decisions

December 4, 2012

(Medical Xpress)—Neuroscience researchers at Trinity College Dublin have opened a new avenue for research on how the brain enables us to make decisions about our environment. By observing the gradual formation of a decision in brain activity before the particular decision was actually reported, the findings also have the potential to contribute to improved understanding and diagnosis of numerous brain disorders that are associated with impaired perceptual decision making. The discovery was recently published in Nature Neuroscience.

When interacting with our environment, we need to be sure about what we're seeing, feeling or hearing in order to decide how to act.  What does that road sign ahead say? Is that a train I hear approaching? Is it too dark for me to cycle home without a light? Somehow the brain enables us to make concrete decisions about the vast and often unreliable array of information it continually receives through the senses. One influential theory about how this might be achieved proposes that the brain allows information from the senses to accumulate over time and only commits to a particular decision once a reliable quantity has been gathered. While this theory has existed for several decades Assistant Professor, Redmond O'Connell at the Trinity College Institute of Neuroscience and colleagues are the first to have identified exactly how this occurs in the

The researchers designed a which required participants to detect a gradual change in a visual display or an auditory tone. The gradual change occurred over several seconds and was undetectable at first but eventually became obvious. This allowed the researchers to pinpoint the precise moment at which participants decided that a change had occurred. At the same time, the researchers recorded using placed on the scalp. Using this method the authors succeeded in isolating a brain signal that increased in parallel with the visual or auditory change and continued to increase thereafter. Most importantly, the authors found that participants only reported perceiving the change once this signal had reached a certain level. As a result, it was possible to precisely predict both the timing and accuracy of the participant's decisions simply by monitoring this . In other words, it was possible to observe the gradual formation of a decision in the participant's brain activity before that decision was actually reported. 

"These findings represent an important breakthrough for neuroscience by opening a new avenue for research on how the brain enables us to make decisions about our environment. Furthermore, by isolating discrete neural signals that are closely tied to behaviour, this work has the potential to contribute to improved understanding and diagnosis of numerous that are associated with impaired perceptual decision making," says Dr O'Connell.

The study was conducted in collaboration with researchers at City College New York.

Explore further: The neuroscience of choosing: Can we understand how the brain makes decisions?

More information: A supramodal accumulation-to-bound signal that determines perceptual decisions in humans. Nature Neuroscience, October 28, 2012.

Related Stories

Recommended for you

New insights on how cocaine changes the brain

November 25, 2015

The burst of energy and hyperactivity that comes with a cocaine high is a rather accurate reflection of what's going on in the brain of its users, finds a study published November 25 in Cell Reports. Through experiments conducted ...

Can physical exercise enhance long-term memory?

November 25, 2015

Exercise can enhance the development of new brain cells in the adult brain, a process called adult neurogenesis. These newborn brain cells play an important role in learning and memory. A new study has determined that mice ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Dec 04, 2012
Acuity of the senses correlates to mental health issues.
What happens to this brain signal (acoustic testing)when varying the amount brain specific estrogen?
The link that follows motivated the question posted above:
not rated yet Dec 04, 2012
See William Calvin ( for decades-old theory of Darwinian evolution of a single thought in the neocortex.
not rated yet Dec 05, 2012
Without the structure of language in any sense, all of Calvin's writings fall apart.
His assertions must hold without resorting to language in any sense.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.