The cerebrum and the cerebellum are the two main areas of the brain. Two thirds of the brain is comprised of the cerebrum, and the other third is comprised of the cerebellum and associated structures. Regarding the cerebrum, I’ll only be referring to it briefly here; for more details on the separate lobes of the cerebrum I’ve added another page entitled Cerebral Lobes: Higher Functions.
There are several specialised areas within the cerebrum. This area of the brain is primarily used for conscious thought and memory storage, but is also responsible for our personality type, our language skills, hormone production and for interpreting the five senses. It is also the engine room responsible for controlling how our muscles work. Just as an example, pick up something close to you. This is referred to as a simple muscle movement.
If this area of the brain is damaged, then it is possible that people may experience the following:
- partial or complete paralysis,
- loss of language skills (i.e. lack of understanding and/or speaking)
- short-term and/or long-term memory loss
- hormonal deficiencies or over-stimulation
- loss of any one of the senses: numbness from loss of touch, deafness from loss of hearing, blindness from loss of sight, and loss of taste and smell.
This happens quite often within stroke victims: due to the loss of oxygen within the brain, different functions are affected depending on where the blockage happened. Unfortunately, though, there is only so much that the brain can take: in minor cases it has the capacity to re-wire itself and the patient can make a full or partial recovery from their injury, but if too much of the brain is compromised, the patient may never recover or may even pass away.
The cerebral cortex is the external layer of the brain. It is composed of grey matter, and is divided into two hemispheres: left and right. Unlike most other brain matter, it lacks insulation between neurons (or Schwann cells). It is composed of gyri, or folded bulges and these gyri create deep furrows or fissures which are referred to as sulci. This part of the brain is both the most advanced and the most recent part of our brain to have evolved.
Cerebellum aka ‘Little Brain’
The cerebellum is the other major centre of the brain, and is responsible for many of the brain’s functions that are done at the subconscious (autonomic) level, which include maintaining balance, muscle tone and as well as more conscious functions such as coordination between different muscle groups. This area of the brain is common within vertebrates. and is often referred to as the ‘little brain’. This part of the brain is also the key centre for fine motor movements. What are they, you may ask? Well, these are the movements which take precision and require a certain amount of training: for example, pick up a pen near you and write something.
That is a demonstration of fine muscle movement: it may be easy to do as an adult, however you may or may not remember spending hours as a kid in primary school learning how to write smoothly with a pencil in your hand and then learning to use a pen.
As the diagram below shows, there are four main parts to the cerebellum: the cerebellum itself, the pons, the medulla and the brain stem. The pons and the medulla are actually considered as part of the brainstem, as both their functions and the structures are similar. Since there are only four parts, I might as well go ahead and tackle them in one section (Brainstem: Communication Conduit) and leave parts of the cerebrum till later, since there’s a lot to go over.
The cerebellum is located inferiorly or below the cerebrum and posteriorly (behind) the pons and medulla. Unlike the pons, medulla and brainstem, the cerebellum itself looks very similar in structure to the cerebral cortex (the outer layer of the cerebrum) in that it has folds of grey matter for its surface layer and white matter located within. The main difference between the cerebellum and the cerebral cortex, however, is that the cerebellum’s grey layer is much more densely folded to increase surface area. The cerebellum is the number one area involved in muscular control: without this area working properly you may end up with the following conditions:
- loss of coordination between muscle groups: instead of your muscular movements being smooth, they end up disjointed and robotic in nature
- slurring in your speech similar to being drunk (albeit with no alcohol in your system)
- movement tremors
- falling when trying to walk, jog or run
- abnormal movements within the eyes
- loss of spatial perception i.e. not being able to properly judge the distance between two objects