The cerebellum is one of the most well-known regions of the brain. While it’s only 10 percent of the brain’s total volume, it holds over 50 percent of the neurons.
Even with all the processing power it has, researchers have assumed it functions outside of conscious awareness. Instead, it helps with mindless bodily functions like standing and breathing.
Last year, however, neuroscientists found it plays a vital role in reward response. This response is one of the significant drives that shapes and motivates human behavior.
While this discovery paves a path for new research possibilities to the region of the brain linked to motor skills and sensory input, there is something more. Now, their latest discovery suggests that the neurons are making up a majority of the cerebellum function in ways we never anticipated.
With how many neurons reside in the cerebellum, there’s little progress in integrating the section into the big picture of how the brain solves its tasks. Part of the disconnect stems from the assumption that the cerebellum only works with motor tasks.
There are hints now as to the connection between the cerebellum and cognitive process. These processes include language function and attention. However, previous research has only ever seen a relationship between these cells and basic sensory or motor functions.
However, there could be much more going on in the region. While the brain holds nearly 60 billion cerebellar granule cells, it’s complicated to study these cells.
Studies with Mice Show the Cerebellum Could be More Complex Than we Ever Though Possible
To better understand how the cerebellum works in mice, a team used a new technique called two-photon calcium imaging. This process allows them to see granule cells and record the activity of the neurons in real time.
The result of this imaging shows a bright green color to the cerebellum. This color is due to a fluorescent protein or GFP. Bioluminescent animals like jellyfish naturally produce this protein.
Interested in what GFP would reveal in the mice, researchers had them move by giving a treat of sugar water each time they pushed a lever.
The expectation was to see how the cerebellum responded to the physical movements. However, it surprised scientists to see a connection between granule cells and the response of reward that the sugar water triggered.
While some granule cells fired when the mice triggered the lever, another part of the same cells activated when the mice waited for their reward.
When the reward left the equation altogether, yet another group of granules went off in the cerebellum.
This instance isn’t even the first time a region of the brain was connected to both reward response and motor coordination. The same two functions drive the basal ganglia as well. This new study hints towards the possibility of the cerebellum being complex similarly.
However, the studies have only tested with mice. It is uncertain it the same similarities will translate to humans.
Even so, the cerebellum is considered one of the more ancient lineages of evolution out of all the brain regions. The wiring in this section is similar across all classes of vertebrates. Therefore, scientists believe there will be a comparable reaction in human brains as well.