Sep 6, 2025 04:28 AM
https://www.livescience.com/health/neuro...-decisions
EXCERPTS: Researchers have completed the first-ever activity map of a mammalian brain in a groundbreaking duo of studies, and it has rewritten scientists' understanding of how decisions are made.
The project, involving a dozen labs and data from over 600,000 individual mouse brain cells, covered areas representing over 95% of the brain. Findings from the research, published in two papers in the journal Nature, suggest that decision-making involves far more of the brain than previously thought.
[...] Based on what you'd read in a neuroscience textbook, said Carandini, you'd expect the brain activity that occurred during the experiment to follow a linear path. First, cells in the visual cortex that recognize images would fire up, followed by neurons in a different part of the brain, such as the prefrontal cortex, known to be involved in abstract decisions. This information might then be combined with additional activity that represented the mouse's prior experiences — in other words, memories — before being sent to motor regions of the brain that control muscle responses.
The researchers' findings supported some of this chain reaction; the visual cortex was the first thing to activate, for example. Yet other findings clashed with the team's expectations.
"We found decision signals and signals related to the prior information in way more brain regions than we might have thought," Carandini said. Taken together, the activity across nearly all of the brain regions studied could be used to deduce whether or not the mouse had received a reward.
In some of the experimental trials, the researchers made the on-screen marker incredibly faint, so the mice essentially had to guess which way to move the wheel. The second Nature paper focused on how the mice used prior expectations — based on where the marker had been in previous tests — to inform their guess. The brain activity that flashed up when the mice guessed in these tasks was also far more widely distributed in the brain than the team anticipated it would be... (MORE - details)
EXCERPTS: Researchers have completed the first-ever activity map of a mammalian brain in a groundbreaking duo of studies, and it has rewritten scientists' understanding of how decisions are made.
The project, involving a dozen labs and data from over 600,000 individual mouse brain cells, covered areas representing over 95% of the brain. Findings from the research, published in two papers in the journal Nature, suggest that decision-making involves far more of the brain than previously thought.
[...] Based on what you'd read in a neuroscience textbook, said Carandini, you'd expect the brain activity that occurred during the experiment to follow a linear path. First, cells in the visual cortex that recognize images would fire up, followed by neurons in a different part of the brain, such as the prefrontal cortex, known to be involved in abstract decisions. This information might then be combined with additional activity that represented the mouse's prior experiences — in other words, memories — before being sent to motor regions of the brain that control muscle responses.
The researchers' findings supported some of this chain reaction; the visual cortex was the first thing to activate, for example. Yet other findings clashed with the team's expectations.
"We found decision signals and signals related to the prior information in way more brain regions than we might have thought," Carandini said. Taken together, the activity across nearly all of the brain regions studied could be used to deduce whether or not the mouse had received a reward.
In some of the experimental trials, the researchers made the on-screen marker incredibly faint, so the mice essentially had to guess which way to move the wheel. The second Nature paper focused on how the mice used prior expectations — based on where the marker had been in previous tests — to inform their guess. The brain activity that flashed up when the mice guessed in these tasks was also far more widely distributed in the brain than the team anticipated it would be... (MORE - details)
