What Does The Brain Look Like?
Hills And Valleys
If you imagine pictures you have seen of the brain, what comes to mind? What does the brain look like? Well, people might say that the brain looks like wrinkles. Or they may say that the brain looks like it is covered in hills and valleys. Perhaps, the brain looks like it has many folds. The brain is sometimes called gray matter, but is it really gray? What does the brain look like? Well, all of the above are correct to a certain degree and for various reasons.
Our brains are enormous, really, and that is not just arrogance. Our brain is so big that it barely fits inside our heads. This may sound silly, but scientists believe that the folds that we see are because our brain is packed inside our skull. In fact, the intelligence of various animals correlates with the number of ridges on the surface of the brain.
In other words, animals with smooth brains like that of a rat or mouse are less intelligent than animals with many ridges like humans and monkeys. To throw in some scientific terms, the “hills” and “valleys” of the surface of the brain and known as gyri and sulci, respectively. The singular of gyri is gyrus and of sulci is sulcus. Certain gyri are known to contain neurons that do certain things.
For example, the dentate gyrus is part of the hippocampus, a brain structure important for learning and memory. Humans have so many sulci and gyri because they are so clever or, put another way, all those gyri and sulci are what makes us so smart!
View Through A Microscope
What does the brain look like through a microscope? The human brain is packed with millions of brain cells called neurons. If you were to look at a single neuron through a microscope (difficult to do because they are usually connected to many, many other neurons) you would see a cell body that looks rather pointy because it is covered in dendrites.
Dendrites receive information by way of chemical signals from other neurons. You would also see one main filament leaving the cell body. This filament is called an axon and it is how electrical signals travel about the brain and body. The National Institute of Aging published an artist’s rendition of a neuron in action shown. Millions of cell bodies reside at the outer surface of our brain, in gyri.
Since they are packed so densely when you look at them with the naked eye, they appear gray; thus, we get the term gray matter. However, if you were to look a bit deeper in the brain you would see millions of axons springing forth from the cell bodies on their way to the spinal cord. These axons, tightly packed and bundled together, appear white to the naked eye. This appearance explains the term white matter.
Generally, when scientists want to look at the brain, they use a fixative like formaldehyde which makes organs like the brain firm. This firmness is critical in order to study the brain’s structure as it would be if you could examine it in a living person.
Astonishingly, if you were to remove a brain without using a fixative, it would collapse under its own weight! In our heads the brain is suspended by membranes and fluid but left on a table, it would collapse into a pile of goo within a few minutes! What does the brain look like? Now you really know!