Introducing the brain: choreography of movement (Introduction)

by David Turell , Friday, September 08, 2023, 22:27 (440 days ago) @ David Turell

From Zebra fish brain studies:

https://medicalxpress.com/news/2023-09-ballet-brain-choreography-movement.html

"Zebrafish, like humans, possess an innate ability to stabilize their vision and position in response to movement. When the world around them spins, their eyes and body move in tandem to maintain stability. This is akin to us steadying our gaze on a fixed point while on a merry-go-round.

"But how does the brain coordinate this behavior? Previous research by the team had shown that different parts of the zebrafish brain were associated with different types of movements. However, the precise relationship between these brain areas and the actual behavior remained unclear.

***

"By applying their analytical approach to a region of the zebrafish brain called the hindbrain, the researchers were able to condense the cacophony of neuronal activity into two main "features," or patterns of activity, that corresponded to specific types of movements, and are presumably generated by separate circuits in the zebrafish hindbrain.

"The first circuit they found is primarily concerned with eye movements, specifically the rotation of the eyes, either clockwise or anti-clockwise. Imagine a fish seeing something spin around in its environment. To keep a stable view of this spinning object, the fish's eyes also rotate, and its tail may move. Essentially, this circuit helps the fish adjust its eyes to keep a constant and stable image of what it's seeing.

"As Feierstein explains, "It's like the brain's way of saying, 'Okay, the world is spinning around me, I need to move my eyes to keep track of it.'" Moreover, the researchers discovered that neurons associated with leftward and rightward rotation were anatomically segregated in the left and right hemispheres of the brain, respectively.

"The second circuit is more involved in what researchers call "vergence" and tail movement. Vergence is the ability of the eyes to move in opposite directions—both eyes moving towards or away from the nose—in response to stimuli.

"This circuit comes into play when the fish perceives a stimulus moving from back to front. Feeling as though it's drifting backward, the fish swims forward to stabilize its position. At the same time, its eyes converge to maintain a stable image. Consequently, this circuit helps the fish adjust its body and eye movements to stay in a stable position.

"As Orger summarizes, "One brain circuit is primarily concerned with eye movements, particularly rotation, to maintain a stable image on the retina. The other circuit is mostly involved in body movement, particularly swimming, in response to visual stimuli to maintain a stable position in the environment. These circuits help the fish adapt to changes in their environment, allowing them to maintain a stable view and position. While the exact mechanisms are still not entirely clear, the study provides valuable insights into how separate circuits in the brain control different types of movements."

***

"What surprised Feierstein and her team the most was the robustness of their findings. "We found these circuits consistently across each individual fish," she notes. (my bold)

"The study suggests that these circuits are neither purely sensory nor purely motor but lie somewhere in between, possibly translating sensory information into motor actions. In essence, the researchers may have found two different "choreographers," each directing their own set of movements to help the fish interact effectively with its environment.

"The team's research not only enhances our understanding of how the brain controls movement but also introduces an analytical method to the field that could serve as a valuable tool for other researchers. "The nice thing about this method," says Feierstein, "is that it can be used by other scientists to better understand the link between neural activity and behavior."

"The study's findings could potentially open up new avenues for understanding conditions where the translation of sensory information to motor commands might be disrupted, such as in certain neurological disorders. Furthermore, the results could inspire new approaches in robotics and machine learning, where the concept of translating sensory data into movement is a fundamental principle."

Comment: this study must apply to the human brain also. Note my bold. Consider the gymnast on a balance beam flipping over landing on her feet. Apes may look like trapeze artists, but they don't become anywhere close.