Researchers identify neuron crucial for navigation
Researchers have recently recognized a neuron in the brains of mice that is crucial for navigation.
Researchers at the University of Michigan in Ann Arbor have recognized a previously unrecognized excitatory neuron in mouse brains. This neuron, they say, is key for navigation.
This finding, which now appears in the journal Cell Reports, may aid scientists’ knowledge of how the area of the brain in charge of navigation - the retrosplenial cortex (RSC) - goes about navigating prolonged distances.
Navigation and neurology
Scientists understand that the RSC is essential for navigation. Actually, if a person’s RSC is damaged, not only can they experience memory loss, but their capability to navigate may also be severely reduced.
For example, a person with a damaged RSC could find it very hard to navigate their usual route from work to home.
However, scientists are less clear how the parts of this cortex interact in order that an individual can navigate successfully.
By identifying this previously unrecognized excitatory neuron, the researchers gained information on what this new neuron does, along with what the other key neuron in the RSC does.
Two types of neuron
The researchers studied the RSCs of mice and produced computational models that were in a position to simulate the realistic reactions of RSC cells to numerous kinds of information.
This allowed them to determine there are two distinct neurons that give attention to different kinds of navigational information.
One type, called common regular-spiking (RS) neurons, taken care of immediately changes in direction of the top. The other type, called low rheobase (LR) neurons, taken care of immediately the head maintaining a persistent direction.
The neurons do this because of variations in how they receive information.
The RS neurons react to significant changes, but following this, they cannot keep firing to receive more information. For the reason that their signals get slower after the initial significant change in direction.
By contrast, the LR neurons fire regularly and more rapidly, plus they can react to more subtle directional changes. This signifies that they could detect really small variations in the positioning of the head that suggest a continuing direction of movement.
‘The Little Neuron That Could’
According to review co-author Ellen Brennan, who discovered the LR neurons, “An easier name for this small yet tenacious little neuron, as suggested by my classmate, would be ‘The Little Neuron That Could.'”
“It’s an ideal name since it highlights the persistence which makes them optimally suitable for code continued direction. Compared, the other typical excitatory neurons here are slow and stubborn.”
As lead study author Dr. Omar Ahmed explains: “Regular neurons in the cortex are proficient at encoding directional information only once you are moving your mind, but what happens whenever your head is still? You still need to know what direction you are facing to ensure that you can use these details to plan your route.
“You ideally need another kind of neuron - a neuron that may consistently encode your orientation over long durations even though your head is not moving.”
The RSC needs both of these neurons working together to assist navigation. As Brennan notes in a video detailing the findings, not having LR neurons that detect directional movement is comparable to having a compass however, not knowing which way North is.
A link to Alzheimer’s disease?
The researchers are actually investigating whether or not these findings will be helpful in focusing on how Alzheimer’s disease impacts these neurons. Alzheimer’s is the most frequent type of dementia. Among other things, it influences a person’s spatial orientation. Currently, there is absolutely no cure because of this condition.
As Dr. Ahmed notes: “The retrosplenial cortex is crucial for spatial orientation, but is probably the earliest brain regions showing dysfunctional activity in [people with Alzheimer’s]. That is probably why almost all [people with Alzheimer’s experience] spatial disorientation and get lost easily - because their retrosplenial cells aren't working because they should.
“By understanding how retrosplenial cells encode compass-like information in healthy versus Alzheimer’s brains, we hope to start out working toward novel therapies.”
- Dr. Omar Ahmed
Source: www.medicalnewstoday.com
