Differences Between Cerebrum and Cerebellum

Cerebrum and cerebellum sound similar, but they both serve different functions. Let's see what they're like and how they relate to each other.

Written and verified by la médico Sandra Golfetto Miskiewicz.

Last update: 14 April, 2023

To understand the differences between the cerebrum and cerebellum, we must know what the nervous system is, which both organs are a part of. This system is so complex that, for its study and understanding, it has been subdivided into parts.

We have a central and a peripheral nervous system. The first contains the organs we’ll devote this article to, and we’ll concentrate on them.

Central nervous system (CNS)

The central nervous system is made up of the brain and spinal cord. It’s protected by a bony structure, which is the skull, at the top, and the vertebrae below.

It’s the true command center, as it receives and interprets information from the external and internal environment and generates responses to control the organs and tissues of the body. It receives information through the senses, interprets signals, can store information in memory, and controls thoughts, speech, movements, and organ functions

The brain is made up of the following organs:

• Cerebrum
• Cerebellum
• Brainstem: This connects the cerebrum and cerebellum with the spinal cord. The parts of the stem are the pons, the medulla oblongata, and the midbrain. It regulates vital automatic functions such as respiration and heart rate, body temperature, wake-sleep cycles, and digestion.

Differences between cerebrum and cerebellum

Although the cerebrum and cerebellum have certain similar characteristics, there are anatomical and functional distinctions. Let’s analyze them.

Cerebrum

The cerebrum is the largest portion of the brain. It’s an organ that weighs approximately 1300 to 1500 grams (2.9 to 3.3 pounds) in an adult. The surface is called the cortex and contains 16 trillion neurons.

It’s divided into two hemispheres: right and left, by a median longitudinal cerebral fissure. Both parts are joined by the corpus callosum, which transmits messages from one side to the other.

The cerebrum is made up of three chemically and structurally different structures that perform different functions:

• Neocortical system: thought and image.
• Limbic system: located under the neocortex – it allows desiring and feeling, as well as coordinating the different types of short and long-term memory.
• R-complex: it’s found below the previous ones and is related to behavior

These three systems constitute the equivalent of three independent but interconnected biological computers. It’s called the triune brain. The total result obtained is greater than each of the functions of the parts separately.

In general, the brain is responsible for voluntary actions. In addition, it’s responsible for the senses and their interpretation. The cortex plays an important role in perception, attention, thinking, memory, and language.

The right hemisphere of the brain controls creativity, spatial, artistic, and musical ability, and visual and spatial interpretation. For its part, the left hemisphere controls comprehension and arithmetic.

Each of the hemispheres is composed of 4 lobes, with their respective functions. In the frontal lobe reside the mechanisms of personality, judgment, planning, problem-solving, speech, and writing.

The parietal lobe interprets language and words, the sense of touch and pain. It also interprets hearing and visual and spatial perception.

In the temporal lobe, there’s understanding of language, memory, hearing, organization, and sequencing. Finally, the occipital lobe interprets the vision.

Cerebellum

The cerebellum is a small organ that’s located in the posterior region, below the brain. It corresponds to approximately 10% of the brain’s weight.

This organ has three layers in its cortex and has 70 billion neurons. It contains more than 50% of the total number of neurons in the human brain.

It has two cerebellar hemispheres joined by the medial vermis. The basal ganglia of the brain coordinate fine movements, together with the cerebellum.

It plays an important role in coordinating involuntary functions such as speaking, sneezing, and coughing. It also coordinates muscle movements, and maintains posture and balance.

Until a few years ago, the area of origin of the reward response, studied by Ivan Pavlov in 1901, was unknown. In 2017, in an article reported in the scientific journal Nature, neuroscientists accidentally discovered a new role for the cerebellum. They looked at a possible connection between cerebellar granule cells and the reward response.

Memory in the brain and cerebellum

Different areas of the brain, corresponding to the limbic system, are responsible for the types of memory. According to the importance of a particular memory, it will be transferred from short-term to long-term memory.

Memory is a complex process that includes the phases of encoding, storage, and retrieval. Likewise, each type of memory has its basic anatomical structure:

• Short-term or recent: Occurs in the prefrontal cortex. It lasts about 1 minute and allows you to momentarily record words or numbers.
• Long-term: This is processed in the hippocampus and the temporal lobe. It’s activated when you want to save information or a memory. It has unlimited space and time.
• Procedural memory: It’s processed in the cerebellum. This organ is responsible for forming memories of learned procedures, such as riding a bicycle or playing an instrument. The created memories are transferred to the basal ganglia.

Complexity makes us human

The nervous system is a very complex system. Both the cerebrum and the cerebellum perform vitally important functions.

And although there are differences between them, they complement each other in their functions. They allow us to relate to the environment and determine actions and personalities, making us unique.