We explain the most developed part of the nervous system in humans.
The forebrain in turn divides into two distinct cell populations, the inner ones that will form the diencephalon, and the outer ones, which form the telencephalon.
The telencephalon is the part of the central nervous system that includes the cerebral cortex, one of the most highly developed structures in humans , compared to other nearby species. Together with the cerebellum, the telencephalon coordinates practically all the voluntary actions of the human body.
In this article we will talk about the telencephalon at a structural and functional level, to better understand where the different parts of the central nervous system come from.
The different parts of the telencephalon and their functions
The telencephalon in vertebrates is the portion of the central nervous system that is farthest from the beginning of the spine, either horizontally or vertically -as in the case of humans-.
This includes different structures, placed not only in the outermost part of the brain, but also forming internal structures.
The different functions of the parts of the telencephalon vary greatly depending on the area we are talking about . Next, we review the different structures of the telencephalon briefly summarizing their function.
1. The cerebral cortex
The cerebral cortex is the part most people think of when they imagine a brain: A structure on top of the rest of the nervous system, with a wrinkled topography , like a walnut.
The cerebral cortex is composed of gray matter , which differs from the white matter of the brain in its ratio of cell bodies to cell axons. The gray matter is rich in neuronal bodies and has a greater information processing capacity, while the white matter is richer in neuron axons, allowing a rapid distribution of nervous information.
The cortex or cerebral cortex covers the rest of the parts of the forebrain, like a helmet . This structure full of peaks and valleys -called gyres and sulci- is divided into two hemispheres, which in turn are divided into 4 main types of cerebral lobes. Its wrinkled structure allows a larger brain volume without an exaggerated increase in the size of the head, which already causes problems for human reproduction at its current size.
The functions of the cerebral cortex are various, depending on the area we are studying. To learn more about the functions of the lobes, we recommend our article about the 6 lobes of the human brain
2. The hippocampus
The hippocampus is a brain region that lies deep within each of the temporal lobes. It has an elongated shape, with a very high neuronal concentration. It is also known as “the organ of memory” colloquially, due to its important role in collecting and accessing long-term memory.
- It might interest you: “Temporal lobe: anatomy, functions and characteristics”
In addition to its functions at the memory level, it is known that the hippocampus influences behavior -inhibiting maladaptive behaviors for the individual in society-, as well as being key in learning processes and navigation in three-dimensional space.
3. The cerebral amygdala
The amygdala represents a small neuronal area with a distinctive almond shape , located in the most central part of the temporal lobe. This structure has a lot to do with the processing of emotions, as it is part of the limbic system.
This means, for example, that the cerebral amygdala is related to the response to fear or pleasure, as well as aggressiveness. Its size in men is 30% larger due to the effect of sex hormones, such as testosterone. Interestingly, this enlargement disappears in case of castration.
Some psychological and psychiatric illnesses, such as autism, depression or post-traumatic stress, are related to dysfunction of the amygdala, either at a structural level or its balance of neurotransmitter activity.
4. The striatum
The striatum – also known as the striatum – is another group of subcortical neurons of the telencephalon, in this case related to the basal ganglia. It is a fundamental part of the motor response and reward mechanisms – our body’s way of motivating us to act -, in addition to serving as the “antenna” of the basal ganglia, through which they receive signals from the rest of the system highly strung.
It is an area of the telencephalon important for conscious processes , such as planning or the ability to make decisions. Its name comes from its “striated” appearance, due to its composition of white matter and gray matter.
Its dysfunction is related to disorders such as autistic disorder or addictions, as well as diseases that also affect movement, such as Parkinson’s disease.
5. The olfactory bulb
The olfactory bulb represents one of the most conserved brain structures among animals. It allows the processing of olfactory information, in part thanks to its privileged position: It is located just above the nasal neurons and the olfactory nerve.
6. The basal ganglia
The basal ganglia are subcortical nuclei of neurons that are also found just below the cerebral cortex. They are related to such important functions as voluntary motor control, learning or emotions. Its largest component is the striatum, which receives signals from other brain areas to communicate with the rest of the components of the basal ganglia.
Bibliographic references
- Amunts K, Kedo O, Kindler M, Pieperhoff P, Mohlberg H, Shah NJ, Habel U, Schneider F, Zilles K (December 2005). “Cytoarchitectonic mapping of the human amygdala, hippocampal region and entorhinal cortex: intersubject variability and probability maps”. Anatomy and Embryology. 210 (5–6): 343–52. doi:10.1007/s00429-005-0025-5.
- Sniffing out the contributions of the olfactory tubercle to the sense of smell: hedonics, sensory integration, and more?”. Neurosci. Biobehav. Rev. 35 (3): 655–668. doi:10.1016/j.neubiorev.2010.08.004.
- Cameron IG, Watanabe M, Pari G, Munoz DP (June 2010). “Executive impairment in Parkinson’s disease: response automaticity and task switching”. Neuropsychologia. 48 (7): 1948–57. doi:10.1016/j.neuropsychologia.2010.03.015
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.