Researchers discover new functions of the ‘ancient brain’

Clarify the brain

The hindbrain is a area of the mind that controls primary important capabilities similar to coronary heart fee, respiratory, and stability. The hindbrain is probably the most primitive a part of the mind and serves as a serious hyperlink between the spinal twine and better mind areas.

A multi-regional hindbrain circuit permits animals to regain their trajectory after deviating from it.

The zebrafish heads in direction of its goal, however the sturdy currents push it off target. Undeterred, the little fish returned to its start line, decided to finish its journey.

How do animals know the place they’re of their surroundings, and the way does this decide their subsequent decisions? researchers in Howard Hughes Medical Institute The Janelia Analysis Campus found that the hindbrain — an evolutionarily conserved, or “historical” area behind the mind — helps animals calculate their location and use that info to determine the place to go subsequent.

New analysis not too long ago printed within the journal cellreveals new capabilities for elements of the “previous mind”, findings that will apply to others[{” attribute=””>vertebrates.

Zebrafish Whole Brain Imaging

This video shows whole-brain recordings of the larval zebrafish taken while it was in the virtual reality environment. Credit: Misha Ahrens

Whole-brain imaging reveals new networks

To figure out how animals understand their position in the environment, researchers, led by En Yang, a postdoc in the Ahrens Lab, put tiny translucent zebrafish, barely half a centimeter in length, in a virtual reality environment that simulates water currents. When the current shifts unexpectedly, the fish are initially pushed off course; however, they are able to correct for that movement and get back to where they started.

While a zebrafish is swimming in the virtual reality environment, the researchers use a whole-brain imaging technique developed at Janelia to measure what is happening in the fish’s brain. This technique allows the scientists to search the entire brain to see which circuits are activated during their course-correcting behavior and disentangle the individual components involved.

The researchers expected to see activation in the forebrain – where the hippocampus, which contains a “cognitive map” of an animal’s environment, is located. To their surprise, they saw activation in several regions of the medulla, where information about the animal’s location was being transmitted from a newly identified circuit via a hindbrain structure called the inferior olive to the motor circuits in the cerebellum that enable the fish to move. When these pathways were blocked, the fish was unable to navigate back to its original location.

This video exhibits a digital actuality surroundings for zebrafish larvae. Fish traverse a two-dimensional surroundings with simulated water circulate. Credit score: Mischa Ahrens

These outcomes point out that areas of the brainstem keep in mind the zebrafish’s unique location and generate an error sign primarily based on their present and former places. This info is transmitted to the cerebellum, which permits the fish to return to its start line. This analysis reveals a brand new perform for the inferior olive and cerebellum, which have been identified to be concerned in actions similar to reaching and locomotion, however not such a locomotion.

“We discovered that the fish tries to calculate the distinction between its present location and its most popular location and makes use of that distinction to generate an error sign,” says Yang, first writer of the brand new examine. “The mind sends this error sign to the motor management facilities in order that the fish can right after being moved by circulate unintentionally, even after many seconds.”

New multidirectional circle

It stays unclear whether or not these identical networks are concerned in related habits in different animals. However the researchers hope that labs that examine mammals will now begin trying within the hindbrain for symmetric circuits for navigation.

Researchers say this hindbrain community is also the premise for different navigational expertise, similar to when a fish swims to a selected location for shelter.

“It is a circuit so unknown for this type of navigation that we expect could underlie higher-order hippocampal circuits for exploration and feature-based navigation,” says Misha Arens, senior group chief at Janelia.

Reference: “Brainstem integrators of self-location reminiscence and postural stability in zebrafish” by En Yang, Martin F. Zwart, Ben James, Mikael Robinov, Zhiqiang Wei, Sujata Narayan, Nikita Vladimirov, Brett de Mensch, James E. Fitzgerald and Misha P. Ahrens, Dec. 22, 2022, Out there right here. cell.
DOI: 10.1016/j.cell.2022.11.022

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