The fissures of the brain are the grooves and folds present on the surface of the cerebral cortex. They are the part that gives the brain its wrinkled appearance ; and its function is fundamental in the development of human intelligence and our higher mental capacities.
Fissures of the brain can be divided into convolutions and sulci, depending on their exact anatomy. Its main function is to increase the surface area of this organ, in such a way that a greater number of neurons accumulate in the cortex. Thus, the information processing capacity increases without having to increase the size of the skull.
Virtually all vertebrate animals present fissures in the brain, but human fissures are the most complex of all. In this article we will see which are the most important, and we will study their main characteristics.
Major brain fissures
Generally, all fissures in the brain are divided into two main types: sulci, or fissures, and convolutions. Although there are a large number of them, some are especially important due to their size or the function they fulfill. We will study some of them below.
The brain sulci are deep clefts that divide the brain into different lobes, in addition to forming the division between the left and right hemispheres . There are generally five of them.
– Interhemispheric groove. Also known as a “medial longitudinal fissure,” it is a deep groove located in the center of the cerebral cortex . It forms the division between the cerebral hemispheres. In addition, the corpus callosum , one of the most important structures, is located inside.
– Lateral groove. Also called “Silvio fissure,” it is a very deep groove that divides the temporal and parietal lobe . It also separates the hippocampal and fusiform gyrus at the bottom of both temporal lobes.
– Central groove. Alternately named “Roland’s fissure,” it divides the parietal lobe from the frontal.
– Calcarine furrow. It is located in both occipital lobes. It is the groove that divides the visual cortex in two.
– Parieto-occipital groove. The last major groove separates the parietal lobe from the occipital one, being one of the deepest cracks in the cortex.
The convolutions are shallower folds located inside the lobes. Although the functions of each of them are not precisely known, some have been studied in depth, and neuroscience has a rough idea of the role they play in our brain. The most important are the following:
– Broca’s area . It is a brain area located in the left frontal lobe . It is in charge of controlling the motor part of speech; that is, the way in which we move the speaking organs to produce language.
– Angular circumvolution. This fold, which is found in the parietal lobe, helps both in understanding language and in processing visual and auditory information that reaches our brain.
– Cingulate gyrus. It is an arch-shaped fold that is located over the corpus callosum. It is part of the limbic system; and its main function is to process sensory information that has to do with emotions. In addition, it is also responsible for regulating aggressiveness and behaviors related to it.
– Spindle twist. This gyrus is found in the temporal and occipital lobes. It is divided into two parts: side, and middle. Although its function is not exactly known, it is believed to play an important role in word and face recognition.
– Hippocampal gyrus. This fold is located in the inner part of the temporal lobe , specifically in the one that surrounds the hippocampus . It plays a critical role in creating and storing memories.
– Lingual twist. The last of the convolutions traditionally considered important has to do with the processing of images received through vision. It is found surrounding the lateral sulcus and the calcarine.
Functions they fulfill
The convolutions and sulci of the brain serve two extremely important functions. On the one hand, these folds increase the surface of the cortex, so the neuronal density also increases. This produces that our capacity to process information is greater, without having to increase the size of our head.
This is something very important at an evolutionary level, since one of the main problems of our species is that our skull is very large. Thus, human delivery is much more complicated than that of most other mammals; if our head were even bigger, the consequences could be disastrous.
At the same time, the convolutions and sulci divide the brain creating boundaries between the lobes and hemispheres, which helps the division of tasks between each of these areas. However, all parts of the brain are interconnected in a certain way.
Division of the brain into lobes
Based on the divisions created by the cerebral sulci, we speak of four different lobes: the frontal, the occipital, the parietal and the temporal. Each of them fulfills a specific function, while helping the rest to carry out theirs.
In this way, the frontal lobe is responsible for functions such as motor control, conscious thinking, and logic. The parietal lobes process information from the senses, while the occipital lobes are specialized for vision. Lastly, the temporal lobe is responsible for tasks related to memory , emotion, and speech.
Variations between people
Interestingly, the distribution pattern of the brain grooves varies between people. It is because of this that it is only possible to name and identify some of the most important ones, which generally have a similar anatomy in all individuals.
In humans, cerebral convolutions appear around five months of age, and take more than a year to fully develop.
The development of these very important parts of the brain varies between individuals, and has a direct influence on the intellectual capacity of each person.
Today, we do not fully understand what causes differences in this regard between various individuals. However, both genetic and epigenetic, as well as purely environmental factors are known to be involved.
- “Gyri and Sulci of the Brain” in: Thought Co. Retrieved on: January 15, 2019 from Thought Co: thoughtco.com.
- “Circumvolutions and cerebral grooves, anatomy and function” in: Psicoactiva. Retrieved on: January 15, 2019 from Psicoactiva: psicoactiva.com.
- “Parts of the brain. Brain anatomy ”in: Cognifit. Retrieved on: January 15, 2019 from Cognifit: cognifit.com.
- “Definition of fissure” in: Definition Of. Retrieved on: January 15, 2019 from Definition Of: definicion.de.
- “Cisura (neuroanatomy)” in: Wikipedia. Retrieved on: January 15, 2019 from Wikipedia: es.wikipedia.org.