The science behind the comic
The Over Exciting Brain Zoo
Chapter 3 ▾
When inhibitory neurons in the brain are no longer doing their job, brain disease is the unavoidable outcome. A prime example is epilepsy. This is characterized by the excitatory neurons getting overexcited. They no longer communicate meaningful information with each other. Instead, they babble simultaneously, causing a loss of thoughts and uncoordinated contractions of muscles that is typical of a seizure. Several other brain diseases are also thought to be a consequence of inhibitory neurons not functioning any longer, for example schizophrenia.
Why do inhibitory neurons stop functioning? The reasons are diverse. Epilepsy patients can have a history of head injury, brain tumors, or infections such as meningitis. But most often, we simply don’t know the cause. What concerns schizophrenia, there is sometimes a genetic origin of the disease.
Many scientists are trying to understand what goes wrong with the different cell types in brain during these brain diseases. Given the vast complexity of the brain, the many brains cells, and the complicated language they speak to each other, understanding how the healthy brain works is daunting, let along understanding what goes wrong during brain diseases.
Chapter 2 ▾
The outer layer of our brain is called the cortex. It is only 2.5 mm thick, yet it contains a vast number of different neurons, many of which we know very little. Modern day neuroscientists are trying hard to understand why we have so many different neurons. For them, this thin sheet of brain is like a vast and deep ocean, full of mystery, waiting to be explored.
At the coarsest level, neurons can be divided in excitatory and inhibitory neurons. Both groups can be further divided into numerous sub-groups, yet it is not known how many sub-groups there are. By the time we have discovered all the creatures that live in this vast ocean that is our brain, we will likely have found hundreds of different types.
While we know little about the functions of the different groups of neurons, we do know that excitatory neurons can’t function without inhibitory neurons. When there is something wrong with the inhibitory neurons in our brain, tragedy happens…
Chapter 1 ▾
Every big question in neuroscience (How does memory work? How can we prevent neurodegenerative diseases? Is free will an illusion?) will ultimately require us to decyper the activity of brain cells. We often tend to talk about the brain as a mysterious black box, but the brain is actually formed by billions of cells (neurons and glia) each one a little mystery in itself. We know that different types of neurons have different chemical and electrical properties, but we are just starting to appreciate the role played by different cells, like the elusive inhibitory neurons studied in Dr. Vervaeke laboratory.
My goal with this story was to convey the sense of mystery and potential for discovery in neuroscience, so I built a story around the metaphor of the brain as an alien ocean. Just like the ocean is home to myriad of different species (many of which still undiscovered) the brain is a complex ecosystem of different types of neurons, which need to be studied and classified. Neuroscientists - like the first marine biologists - face many technical challenges when studying neurons, especially because 'captive' neurons in a laboratory may behave differently than they do in their natural environment.