Occipital Lobe: Structure And Functions

Take a deep breath and take a look at everything around you right now, take your time. The world is full of beauties, of small nuances that make up our passionate reality. If most of us are able to perceive every visual stimulus that surrounds us, it is essentially due to the occipital lobe, an  area of ​​our brain located at the height of the nape of our necks.

It is amazing how this region, being the smallest among the rest of the brain lobes, is the one that most marks our daily life. Its main purpose may seem simple at first: to receive information through our eyes, then process it and lead it to the frontal lobe for it to respond.

Now, if we take a careful look at the look around us, we’ll realize that this task isn’t as easy as it sounds. When our brain looks at each stimulus, it carries out a large number of processes. It analyzes distances in relation to our position, movements and sizes, and also processes light (color).

This is something we do without being aware, it implies a high neurological sophistication, an absolute precision, where the occipital lobe allows us to move effectively in our daily lives. It’s small, but highly specialized and effective. Let’s look at some more information about it.

Occipital lobe: location and structure

The occipital lobe is located in the posterior area of ​​the cerebral cortex. It occupies about 12% of the neocortex and is linked, in turn, to the primary visual and association cortex, and to the calcarine sulcus, a convolution that is just inside it. All of these connections constitute a neural center of human vision and visual perception.

We can also say that, as with all of our brain lobes, it has a left hemisphere and a right hemisphere. However, each is isolated from the other by the separation of the cerebral fissure, relying, in turn, on the cerebellum and dura mater.

Functions and areas of the occipital lobe

Our understanding of the world is based almost exclusively on the sense of sight. The occipital lobe processes visual stimuli permanently, analyzing distances, shapes, colors, movements…

Everything that arrives through the retina passes through this analysis and processing center, which then sends the information to the cerebral cortex. However, this transfer of information must first pass through a number of areas. Are the following.

• Primary visual area or region 17 Brodmann. We are in the most posterior region of the occipital lobe, also known as V1. In case of suffering an injury in this region, the person would be unable to see because he could not process any stimulus, even if his retinas and eyes are in good condition.
• Secondary visual area (Brodmann’s 18) or V2. Here we find the prestriatal cortex and the inferotemporal cortex. The first, in addition to receiving information from the primary visual area, is also responsible for stimulating memory. That is, we can associate visual stimuli with others seen previously. On the other hand, the inferotemporal cortex helps us recognize what we see.

• Tertiary visual area (19 of Brodmann) or V3, V4 and V5. This area receives information from the previous structures. Its main function is to process colors and movements.

Occipital lobe injuries

Falls, traffic accidents, strokes, infections; there are many conditions that can cause an injury or change in the occipital lobe. These injuries can be permanent, as revealed by a study conducted at Nihon University, Tokyo, Japan.

Let’s see what the most common effects are.

blindsight

Blindsight or cortical blindness appears as a consequence of bilateral damage to the primary visual cortex. Patients with this problem see diffuse shapes, vague stimuli with which they cannot recognize either the shape or the color or the situation, and not even whether they are moving or not.

visual hallucinations

Damage to this area of ​​our brain can also produce something as impressive as it is shocking: visual hallucinations. The person can see what surrounds him in a distorted way, with strange colors, with distorted sizes, too big or too small…

Epilepsy

The Department of Neurology at Yale University School of Medicine in New Haven explained through a study the relationship between the occipital lobe and epilepsy.

These are cases in which the patient, as a result of being exposed to a glare of intense light, may suffer an epileptic attack by overstimulating the neurons in that area. It is, therefore, another type of epilepsy, related to that specific part of our brain.

To conclude, we can say that the occipital lobe may be related to other processes that go beyond vision. Neurologists believe that it is also involved in the memory process, but to date we have no conclusive studies.

In the coming years, and as we discover each of the mysteries of the human brain, we will have more answers and better insights.