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Our research explained

About the brain

PREMSTEM research and the brain

Many of PREMSTEM’s researchers are experts in disorders related to the brain, such as cerebral palsy, and together bring years of experience studying different types of brain injury to the project. As a team, we’re trying to find a new therapy to reduce the effects of brain damage sometimes suffered by preterm babies. 

On this page we share our interest in the brain – one of the body’s largest and most complex organs!

Humans only use 10% of their brains

True or false?

False

Evidence shows that we use 100% of our brains over a day – just not always at the same given moment

What is the structure of the brain?

The brain consists of different parts with different functions. They work together to allow us to perform different types of task, from standing up to breathing – tasks the average person does without even thinking.

  • Cortex: The outermost layer of brain cells, the cortex is where thinking and voluntary movements originate.
  • Brain stem: Between the spinal cord and the rest of the brain, the brain stem controls basic functions like breathing and sleep.
  • Basal ganglia: A cluster of structures in the centre of the brain that coordinates messages between other areas of the brain.
  • Cerebellum: At the base and back of the brain, the cerebellum is responsible for coordination and balance.

The brain’s four lobes are also involved in different types of everyday task and bodily function.  

  • Frontal lobes: Problem solving and judgement, motor function.
  • Parietal lobes: Sensation, handwriting, body position.
  • Temporal lobes: Memory, hearing.
  • Occipital lobes: The location of the brain’s visual processing system.

Source: WebMD

Credit: marina_ua (Getty Images)

Why is the brain vulnerable?

We all know that the brain is an important organ in our body. It’s also a very delicate and vulnerable one! To find out why, we’ve profiled different types of cell in the brain to find out what they do – and why a preterm birth can be disruptive to their development.

Credit: marina_ua (Getty Images)

Brain cells

9 Videos
Neural stem cells are the brain’s building blocks! Like other stem cells found in the body, those in the brain – neural stem cells – can self-renew and make more versions of themselves. They also have the amazing ability to become other specialised cells in our brain: neurons, oligodendrocytes and astrocytes! Studies of brain injury related to preterm birth has reported that there are changes in the number of neural stem cells and the type of cell they’re able to differentiate into.
Radial glia: the brain’s traffic controllers! Radial glia provide a platform for directing young neurons to get where they need be; the neurons journey along the radial glia fibres to reach their destination. The long-tailed radial glia are heavily involved in the development of the brain. Besides overseeing the neurons they also bring about the birth of other brain cells, including astrocytes and oligodendrocytes. What’s more, the interactions between radial glia and endothelial cells are vital for building the blood-brain barrier – the body’s mechanism for keeping nasty substances and organisms like bacteria and viruses out of the central nervous system. Studies of brain injury related to preterm birth have shown that the ability of radial glial to divide, their shape and overall number can be altered.
Purkinje cells are a type of neuron and are found in the cerebellum – a small part of the brain responsible for coordinating our muscle movements. They are easy to recognise for their tree like structure, with ‘branches’ called dendrites spreading out to create what looks like a forest in the brain! The Purkinje cells are found in the Purkinje layer of the cerebellum alongside Bergmann glia. Below this layer is a layer of granule cells. These cells have fibres which climb up the Purkinje cell, a bit like ivy winds around a tree. These fibres create hundreds of connections (synapses) as part of a large circuit. Purkinje cells help us to coordinate and regulate our movements. When damaged, problems can arise with coordination, balance and speech. Studies of brain injury related to preterm birth have shown that the overall development of the cerebellum is disrupted by preterm birth as its growth continues into the third trimester of pregnancy, when preterm born infants are already born. As a result, the number of Purkinje cells and the shape and span of the complex ‘dendritic tree’ of these beautiful cells can be altered.
Astrocytes are a star-shaped glial cell with an important relationship with neurons. Did you know that Einstein’s brain had more astrocytes than the average person’s? These cells have long extensions coming off their bodies, allowing them to be in contact with thousands of neurons, which they help to keep healthy by providing vital nutrients. Astrocytes also help to form the blood-brain barrier (BBB). The BBB is a special wrapping around the blood vessels in the brain. The BBB is like a sieve that allows good things from your blood into your brain while keeping the bad parts out. In the developing brain of a baby, disruption to astrocyte activity can lead to lasting neurodevelopmental disorders.

Bergmann glia are a type of astrocyte found alongside the Purkinje cells in the cerebellum. Bergman glia are numerous, outnumbering Purkinje cells 8 to 1! Bergmann glia play a role in the migration of granule cells up to the granule layer early in the development of the cerebellum. Like other astrocytes, Bergman glia play a supportive role to neurons and help to regulate the brain’s oxygen supply. They help to optimise the information processing and carry out housekeeping activities. They are also thought to be important for neuroprotection, playing a part in controlling calcium levels in the brain. Calcium imbalance has been linked to neurodegeneration and diseases like Alzheimer’s. Studies of brain injury related to preterm birth have shown that Bergman glia are also vulnerable to injury – with decreased number and altered shape and size.

Oligodendrocytes are one of the last types of cell to form in the brain. The brain grows rapidly in the final trimester of pregnancy, at a time when a preterm baby is having to grow outside the mother’s body. This is due in part to the work undertaken by oligodendrocytes – disruption to their work makes the preterm brain particularly vulnerable and prone to injury. Oligodendrocytes are primarily responsible for wrapping the neuron axons with myelin, a process known as myelination. Myelin helps the neurons to send messages quickly around the body. Oligodendrocytes also supply proteins to neurons which keep them healthy and help them to form connections (synapses) for passing messages to each other. Being born early interrupts oligodendrocyte development and can mean lasting problems in the preterm brain and its ability to send instructions.
Pericytes play an important role in the central nervous system and help with the upkeep of the blood-brain barrier (BBB). In fact, a lack of pericytes has been shown to promote death of neurons and prevent the proper function of the BBB. Pericytes wrap around the walls of small blood vessels called capillaries. They help to maintain and regulate the blood flow in the brain – a pericyte in ‘relaxation mode’ causes capillaries to dilate, and blood flow is increased. Pericytes also help to form new blood vessels. Besides supporting the brain’s vasculature health, we think pericytes also play a role in the recovery of muscle mass as they help control the flow of blood. There are not many studies of pericytes in brain injury related to preterm birth. There are links to changes in pericyte number due to impaired blood vessel development and links to altered maturation of oligodendrocytes.
Interneurons are found in the brain and spinal cord (the central nervous system or CNS). If the brain were an orchestra, the interneurons would play the role of the conductor! They help to tune and balance the excitatory signalling of the brain, allowing them to regulate the many activities which are taking place across the CNS. Specifically, they create the circuit between sensory and motor neurons – cells which take information in and then pass messages to parts of our body. Scientists have found links between preterm birth and a disruption in the number and location of interneurons – another reminder that the developing brain is vulnerable!
Polydendrocytes are the brain’s ‘mystery glia’. Although they are found in both the white and grey matter, we know very little about them. They are mysterious as we have always confused them with ‘baby’ oligodendrocytes. Now we think that polydendrocytes not only give rise to oligodendrocytes, but maybe even neurons and astrocytes. Importantly, polydendrocytes don’t have to become anyone else to play a key role in immune responses to injury and remyelinating, by releasing chemicals into the brain. Polydendrocytes also interact directly with neurons, for example by supporting the growth of axons and signalling. We think that disruption to the timing and appearance of polydendrocytes can cause negative effects to the developing brain and affect the process of myelination.
Microglia: the housekeepers, gardeners, and protectors of the brain! Microglia make up 10-15% of all brain cells and are important for keeping the healthy brain clean and well organised. When activated in response to brain injury or infection they get to work destroying any invaders and trying to fix problems. A frequent cause of preterm birth is infection originating inside the uterus. As a response to the infection, the baby’s microglia switch from their healthy role of building the brain to protector mode, but this often does more harm than good, causing brain injury. Overactivated microglia also cause brain damage in disorders such as Alzheimer’s, stroke and traumatic injuries. Understanding how microglia change during injury could be vital to understanding how to protect the brain, in both younger and older people.
Endothelial cells form a protective inner layer around every blood vessel in the body, including in the brain where they help to form the blood-brain barrier (BBB). Without these cells, our blood vessels would not work properly. They also promote healthy blood flow by releasing nitric oxide which controls the dilation of blood vessels so they can provide more nutrients to the brain where it is needed. In the BBB, the endothelial cells fuse together and form junctions to ‘plug’ the gaps which would otherwise allow anything in the blood to enter the brain. This selective barrier protects the brain from many drugs or toxins. Studies of brain injury related to preterm birth have shown that an immature vasculature may predispose infants to bleeding in the brain and impaired transfer of nutrients from the blood to the brain across the blood vessels.
Perivascular macrophages (PVM) are a type of immune cell found in the space around blood vessels, especially arterioles which branch off the artery. PVM migrate into the brain early in the development of the central nervous system. As they can self-renew, they are with us throughout our life! Not as much is currently known about the PVM compared to other brain cells although they play a key role in which cells move into the brain from the blood (transmigration). However, scientists are starting to investigate their role in processes which are linked to certain brain diseases. Studies of PVM in model of brain injury related to preterm birth are also limited, but they have been shown to change in number, shape and gene expression.

Did you know?

A look inside the brain - images from the PREMSTEM labs

More information

Take a look at our fact sheet on preterm birth and brain injury, available to download in nine languages. 

For more brain facts, check out the following websites:

11 Fun Facts About Your Brain

25 Amazing Facts About the Human Brain You Should Probably Memorize

Brain Facts that make you go, “Hmmmmm”

Brain truth or myth 

How the brain works: Test your medical IQ 

PREMSTEM brain fact sheet (English)
Health risks related to preterm birth
Neonatal encephalopathy

PREMSTEM: The brain injury in the premature born infant: stem cell regeneration research network

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 874721. Results reflect the author’s view only. The European Commission is not responsible for any use that may be made of the information it contains.

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