Nav: Home

Structural development of the brain

June 21, 2019

The human brain consists of neurons arranged into microscopic columns. The cortex, which is the seat of most cerebral functions and forms the largest part of the brain, is divided into uncountable micro-columns. However, the exact development of this columnar structure is elusive to neuroscientists. A research team led by Makoto Sato, has recently reported their study describing the role of a specific protein in the growth of these columns.

The team spanning across Kanazawa University, Ryukoku University, Tokyo Institute of Technology and Imperial College London, used the Drosophila melanogaster (fruit fly) brain for their experiments. The visual centre of the Drosophila brain bears high structural resemblance to the columnar arrangement of the human one, making it an apposite, yet simple model to study. To first visualize these columns, N-cadherin (Ncad), a protein specific to the nervous system, was mapped. The spatial locations of Ncad revealed that during the larval stage of the fly, the visual centre comprised a donut-like structure. As the fly matured to the pupal stage, these structures started stacking on top of each other and indeed transformed into a three-dimensional column.

The research team then carefully analysed these columns and found the presence of three neuron types, namely, R7, R8 and Mi1 within them. While R7 was concentrated towards the central core of the columns, R8 and Mi1 were arranged towards the periphery. Now that the structural composition was clear, understanding the process of column formation was the next step. It was suspected that Ncad, which was heavily present in the columns, played a role in this regard. When Ncad was measured in all three neuron types, it was found that R7 neurons contained more Ncad than the peripheral neurons. Since Ncad is known to give cells adhesive properties, the team concluded that it was the levels of Ncad which determined the location of each of the neuron types within the columns. Heavily adhesive neurons such as R7 formed the core of the columns.

Lastly, to see whether Ncad directly affected the columnar arrangement, it was either completely removed or greatly increased in the neurons. As expected, manipulation of Ncad disturbed the columnar assembly and positions of the neurons. For example, R7 neurons without any Ncad were no longer within the core. However, when Ncad was greatly increased within them, the R8 and Mi1 neurons extended towards the core, possibly due to the strong adhesive properties of Ncad.

This study revealed the role of an adhesive protein in arranging neurons to form the columnar microstructure of the brain. "[Ncad-dependant] differential adhesion and inter-layer interaction may be the essential mechanism underlying the 3D organization of column formation that is evolutionarily conserved from the fly optic lobe to mammalian brains", conclude the researchers. This discovery can help neuroscientists monitor healthy development of the brain and uncover other molecules involved in the process.
-end-


Kanazawa University

Related Neurons Articles:

How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Astrocytes protect neurons from toxic buildup
Neurons off-load toxic by-products to astrocytes, which process and recycle them.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
The salt-craving neurons
Pass the potato chips, please! New research discovers neural circuits that regulate craving and satiation for salty tastes.
When neurons are out of shape, antidepressants may not work
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medication for major depressive disorder (MDD), yet scientists still do not understand why the treatment does not work in nearly thirty percent of patients with MDD.
Losing neurons can sometimes not be that bad
Current thinking about Alzheimer's disease is that neuronal cell death in the brain is to blame for the cognitive havoc caused by the disease.
Neurons that fire together, don't always wire together
As the adage goes 'neurons that fire together, wire together,' but a new paper published today in Neuron demonstrates that, in addition to response similarity, projection target also constrains local connectivity.
Scientists accidentally reprogram mature mouse GABA neurons into dopaminergic-like neurons
Attempting to make dopamine-producing neurons out of glial cells in mouse brains, a group of researchers instead converted mature inhibitory neurons into dopaminergic cells.
More Neurons News and Neurons Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.