Where does the brain process information?

In this post we are going to answer the question ‘’Where does the brain process information?’’ We will identify the areas of the brain responsible for collecting, transmitting and processing the information belonging to the senses, their structures and main tasks.

Where does the brain process information?

The brain processes information in the cerebral cortex sent by the thalamus.

What is the cerebral cortex?

The cerebral cortex refers to the outer layer of the brain. This layer is made up of a thin film of nervous tissue that surrounds the surface of the cerebral hemispheres, with primates having a much more developed cerebral cortex than other animals.

Thanks to the correct functioning of the cerebral cortex, humans have the ability to perceive what happens and surrounds us, as well as to imagine, think, have judgment and decision and, finally, the ability to understand and produce language.

Despite the fact that, as explained above, the cerebral cortex is a thin layer of neurons and neuronal connections, it is not homogeneous, since it is made up of six layers of cells, each one with specific and specific functions.

Cerebral cortex classification

If we rely on both the structural and phylogenetic perspective of the cerebral cortex, three different classes of it can be distinguished. These are the following.

1. Archicortex

Evolutionarily speaking, it is the oldest part of the cerebral cortex. Formed by the hippocampus, the archicortex is responsible for those automatic responses and physiological mechanisms responsible for survival.

2. Paleocortex

Phylogenetically, the paleocortex is halfway between the most primary areas of the cerebral cortex and the most evolved. This kind of cortex houses the endings of the olfactory pathways, where the olfactory brain of people is found here.

3. Isocortex or neocortex

It is the most recent area of the cortex, and the one in charge of reasoning processes and abstract thought. These regions of the central nervous system receive input from highly varied structures, and integrate this information to give way to general concepts.

Cerebral cortex layers

As mentioned above, the cerebral cortex is made up of different layers of neural tissue known as gray matter. Each of these layers has a different functional specialization and originated at a different time in human evolution.

This means that, throughout our evolution and development as human beings, these layers have increased in quantity, which has implied a powerful development of our cognitive and intellectual capacities in comparison with other animal species.

These layers are as follows.

1. Molecular layer

The molecular layer is the outermost, and therefore the most recent in origin, of all the layers of the cerebral cortex.

Also known as the plexiform layer, it is essentially a synaptic layer formed by a thick network of neuronal fibers.

2. Outer granular layer

The second layer that makes up the cerebral cortex is the outer granular layer. This is formed by a large number of small stellate and pyramidal cells.

The axons of this layer infiltrate the molecular layer, entering into more submerged areas of the cerebral cortex, coupling with different areas of the cortex.

3. Outer pyramidal layer

The outer pyramidal layer gets its name from the type of cells that make it up: pyramidal cells. These cells direct their axons to other areas of the cortex and to other subcortical destinations in the form of projection, association, and commissural fibers.

4. Inner granular layer

This layer is essentially formed by a compact mass of stellate cells, most of which receive input from the thalamic area. These horizontally arranged fibers are known as Baillarger’s outer band.

5. Inner pyramidal layer, or ganglionic layer

This fifth layer contains a large number of medium to large pyramidal cells, as well as stellate and Martinotti cells. Its horizontally arranged filaments also make up part of Baillarger’s inner band.

6. Multiform or polymorphic layer

The last of these layers is formed by spindle-shaped cells which derive information to the cortex, the thalamus and the striated nuclei. In addition, it also includes pyramidal cells with a triangular or ovoid body.

Its areas and functions

In addition to the types of cortex and the layers that make it up, the cerebral cortex can be divided according to its different functional areas. That is, according to the functions or tasks carried out in each of these areas.

Taking this classification into account, the cerebral cortex can be divided into sensory, motor or association areas.

1. Sensory areas

The sensory area receives sensory information from specific nuclei in the thalamus. This information is sensitive in nature, which means that it carries the information perceived by the different senses: sight, hearing, smell, touch, taste …

This same area can also be divided into two different sensitive areas. The primary sensory area, which has direct connections with peripheral sensory receptors; and the secondary sensory and association areas, which receive sensory information from both the primary association area and the lower areas of the brain.

The objective of the different association zones, both primary and secondary, is to create patterns of recognition and behavior through the assimilation of sensory information. These sensitive areas of the cerebral cortex are:

  • Primary somatosensory area.
  • Primary visual area.
  • Primary olfactory area.
  • Primary auditory area.
  • Primary gustatory area.

2. Motor area

The areas responsible for the brain mechanisms associated with body movement are located in the anterior portion of both hemispheres, that is, in the frontal lobe. In the motor area, the descending motor treatments that start from the cerebral cortex towards the motor neurons of the trunk and the spinal cord originate.

Within this region we find two essential areas for our operation:

  • Primary motor area.
  • Broca’s language area.

3. Association area

Finally, the areas of association are those that make possible the existence of the most complex and abstract mental functions such as memory and cognition mechanisms, the control of emotions, the ability to reason, and the will. In addition, they also have an influence on the development of personality and intelligence.

Role of the thalamus in information processing

The thalamus is an oval-shaped structure that constitutes the dorsal portion of the diencephalon. It transmits sensory input to the primary sensory zones of the cortex, but is more than just a repeater station.

The main function of the thalamus is the integration of sensory information directed to the cortex. It transmits most of the information that reaches the cerebral cortex and, in addition, it integrates various sensory modalities and facilitates or inhibits projections towards one lobes or another.

It is essential for the maintenance of cortical activity. It is also responsible for transmitting information from the cerebellum and the striatum to the cerebral cortex.

The cerebellum and striatum are centers that modulate the descending motor pathways of the cerebral cortex. Almost all sensorimotor information passes through the thalamus before reaching its destination (cortex).

The thalamus is organized into different nuclei with different functions. The only sensory information that does not take over from the thalamus is olfactory information, which passes directly from the olfactory bulb to the cerebral cortex.

The rest of the senses: taste, sight, touch and hearing are released in the nuclei of the thalamus and then project it to its corresponding area in the cortex.

But in addition to the ascending information, it also deals with the descending information, the information that the crust sends to other areas. 

Although its main function is to regulate sensorimotor projections, it is also involved in the functioning of some higher functions, such as memory or language.

How do the cerebral cortex and thalamus communicate? Thalamic-cortical connections

Communication between the cortex and the thalamus is reciprocal and bidirectional. The thalamus consists of projection neurons that aim to communicate with other areas, such as the cortex, cerebellum, or basal ganglia.

In addition, it also has interneurons that send information between the nuclei of the thalamus. Thus, the relay nuclei send projections to specific areas of the crust.

Each sensory modality has its relay nucleus, except for the smell. The sensory relay nuclei transmit their signals to specific areas of the cortex located in the parietal, occipital, temporal, and insula lobes. In addition, each sensory relay thalamic nucleus receives projections from the brain area to which it projects.

Those with diffuse projection include the intralaminar group, the midline group, and the reticular group.

The first two are characterized by the fact that information from different areas of the brain and spinal cord converges on them, and, in turn, they distribute it to large areas of the cerebral cortex, without respecting the limits of the cortical areas.

The thalamus not only functions as a station that processes and transmits the signals it receives to the cerebral cortex, but also acts as a center that controls the signals that reach it. The reticular nucleus performs this function of controlling cortical activity.

The function of the thalamus is crucial for the functioning of our CNS, its injury would lead to various deficits.

As can be seen, its role cannot be limited to a single function: it modulates multiple sensory, motor and even higher functions.

It can be stated, therefore, that the thalamus plays an important role in different brain functions including memory, emotions, the sleep-wake cycle, and executive functions. It is involved in general cortical responses of alertness, sensorimotor control, and processing of sensory information.

FAQS:  Where does the brain process information?

What part of the brain processes information?

The data that the five senses accumulate enters the cerebral cortex. This information is then sent for further processing to other areas of the nervous system.

How long does it take the brain to process information?

The human brain takes about 200 milliseconds to process and become aware of the signals from the environment it receives.

How does brain retain information?

The researchers found evidence that the information was continuously repeated in the mind and identified that the neural mechanism responsible for coordinating this repetition was rhythmic brain oscillations called theta oscillations, which occur at a frequency between 4 and 8 Hz.

How the brain processes sensory information?

Information processing begins with the input of the sensory organs, which transform physical stimuli into electrochemical signals.

Does the brain process information?

Yes, the brain processes information from outside.

In this post we answered the question ‘’Where does the brain process information?’’ We identified the areas of the brain responsible for collecting, transmitting and processing the information belonging to the senses, their structures and main tasks.

If you have any questions or comments please let us know!

References

Horton, J.C.; Adams, D.L. (2005). The cortical column: a structure without a function. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 360(1456): pp. 837 – 862.

Moerel M, De Martino F, Formisano E (2006). An anatomical and functional topography of human auditory cortical areas. Front. Neurosci. 8(225): 225.

Noback, C.R.; Strominger N.L.; Demarest, R.J.; Ruggiero, D.A. (2005). The Human Nervous System: Structure and Function (Sixth ed.). Totowa, NJ: Humana Press. ISBN 1-59259-730-0.

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