Which direction do you turn your head first when crossing the road? This decision depends on where you are. A pedestrian in the US turns his head to the left, while a pedestrian in the UK turns his head to the right. A group of researchers at Columbia's Zuckermann Institute examined how mice use their context when making decisions. Their findings point to a new region in the brain for this process: Anterior lateral motor cortex (ALM). This region was previously prominent in planning movements.
This discovery, published in the journal "Neuron", offers a new perspective on the brain's decision-making process. Flexible decision-making is a critical tool for making sense of our environment; It allows us to react differently to the same information by taking the context into account.
Neuroscientist Michael Shadlen, one of the authors of the article, mentions that "context-dependent decision making" is the basic building block of human high-level cognitive functions: "In the study, we observed this function in the motor area of the mouse brain. It brings us closer to understanding brain cells and neural networks."
Another writer, Zheng Wu, makes the following assessment on the subject: "If a person is standing uncomfortably close to me on a deserted street, I may consider running away at that moment." "However, if this situation happens in a crowded street, I do not feel in danger. Taking action or not is determined by the context I am in. In other words, there are reasons behind my choices."
To explain how the brain achieves context-dependent plasticity, researchers examined brain regions involved in processing and integrating sensory information. However, the critical area was the ALM region in the motor cortex. Based on the information available, the researchers designed a new experiment in which the mouse could make flexible decisions using its tongue and olfactory systems. Accordingly, the mouse was first exposed to a single odor. The mouse had to remember this smell because the researchers blew a second smell at it. If both odors were the same, the mouse had to take water from the tube on the left. If it was different, he had to head to the tube on the right.
Containing such "delayed matching" tasks Previous studies indicate that the mouse will determine its direction with the guidance of the brain regions responsible for smell. Brain activity records obtained in the study also confirmed this mechanism. Regarding the subject, Dr. Shadlen says that when the mouse smells the second scent, the relevant regions of the brain have the answer to the question of where it will go: "All you have to do is answer the question of whether the mouse will go left or right before the motor regions of the brain."
If that were the case, the second The motor regions did not play any role until the mouse smelled the smell and could decide whether the two odors were the same or different. Dr. Wu devised a nice test to measure this prediction. It would deactivate the mice's ALM region until just before the second odor and activate it just in time.
According to the standard view, the mouse should not have been affected by this manipulation as long as the odor region was not intervened. However, we intervened during the mission instead.
Dr. Shadlen
Our results suggest that we need to significantly rethink what the brain does for ALM to solve the question of whether two odors match and then decide which direction to go.
Dr. Wu
ALM was a region known to be involved in odor perception. Dr. While closely examining the cells in this area, Wu discovered a new cell located close to the brain surface that responds to initial fear. This cell retained the information until it smelled the second scent. Faced with this unexpected result, the research team turned to theoretical neuroscientist Ashok Litwin-Kumar to explore several potential mechanisms that could explain the role of ALM: He had to inform . But the data told us a different story; The first odor served as a contextual cue, allowing the ALM to decide which way the mouse would go in response to the second odor.
Today's findings are important as they focus on ALM so that scientists can gain a broader understanding of brain function as a whole.
Ultimately, they reveal fundamental principles that explain simple behavior. We want to mix. However, these important results give us insight into higher-level cognitive functions. An important step towards this goal can be taken by bringing together information about neurons, circuits and behavior using the languages of biology and mathematics. The study highlights the promise of this strategy
Dr. Shadlen
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