The temporal lobe is one of the four large lobes into which the cerebral cortex is divided.. It is especially involved in auditory processes, memory, vision, and the regulation of emotions (due to its connections with the limbic system).
In this article we will know the characteristics of this lobe, as well as its functions and anatomical characteristics. Finally, we will talk about the symptomatology caused by the different lesions, depending on the area of the affected lobe.
Temporal lobe: definition and characteristics
The temporal lobe is an area of the brain, specifically one of the four brain lobes into which it divides.
This lobe encompasses different areas, each specialized in a particular function or task: these are hearing, memory, understanding language and smell, among others. Later we will learn about the different functions of the temporal lobe.
It’s the second largest structure in the cerebral cortex. (the first is the frontal lobe).
In the cerebral cortex we actually find two temporal lobes: one that is located in the left hemisphere, and the other in the right hemisphere. Silvio’s fissure is the structure that divides these two lobes.
The temporal lobe is the lobe that establishes more connections with the limbic system, a system related to emotions, pleasure and memory, among others.
The temporal lobe occupies about a quarter of the cerebral cortex. Anatomically, where is the temporal lobe more concretely located? It is located in front of the occipital lobe (the lobe in charge of vision), that is, behind the temples. Thus, it is located on the lower side of the brain (very close to the ears).
What does this lobe delimit with? In the upper region, the temporal lobe “attaches” to the parietal lobe (limits with it); in the posterior region, however, it “attaches” to the occipital lobe, and in the anterior region, to the frontal lobe.
On the other hand, we can divide the temporal lobe into “three large zones”: one of them, related to object recognition, another to long-term memory, and another to the processing of auditory information.
What functions is the temporal lobe involved in? We will talk about the seven most outstanding and relevant below.
Recognition of faces and objects
This function is located in the visual cortex of the temporal lobe. This bark, too, allows to categorize the different visual stimuli that present themselves in the environment.
2. Language development
The main structure of the temporal lobe that participates in language development is the supramarginal twista small structure located in the tertiary sensitive area.
3. Key role in hearing
In this lobe is the primary auditory cortex.in charge of processing auditory information. As we will see later, lesions in the temporal lobe imply alterations in the auditory processes. That’s why this lobe is considered the “ear lobe” par excellence.
4. Execution of the memory
Has a key role in auditory memorybut also in others (especially the hippocampus).
On the other hand, the temporal lobe plays a key role in declarative memory (i.e., the conscious recollection of experiences); specifically, the medial temporal lobe develops this function, formed by the following structures: hippocampal region, perirrinal cortex, entorrinal cortex and parahipocampal cortex. These structures also connect with the cerebral cortex, allowing memory processes.
5. Establishing body balance
Another function to which the temporal lobe is related is the regulation and establishment of body balance. In addition, balance is also related to ear structures.
6. Regulation of emotions
The main area related to the regulation of emotions in the temporal lobe is the area of association of the limbic system.. This area also allows us to integrate information from other areas with the affective experiences we are living.
7. Other psychological processes
The temporal lobe is involved in motivation processesas well as in the regulation of emotions or states such as pleasure, anger and anxiety.
What happens if you injure the temporal lobe? It all depends on the injured area. Symptoms are especially related to memory disorders, hearing disorders and visual disturbances.
1. Bilateral upper temporal circumvolution
If this area is injured, two things can happen: whether the injury is bilateral (i.e., occurs in both brain hemispheres) or unilateral (occurs in only one hemisphere, either right or left). Remember that the brain is divided into two equal hemispheres, the right and the left (it is as if we divided a sphere into two halves).
So, in the event that the injury is bilateral, cortical deafness occurs. Cortical deafness causes a loss of hearing (in both ears) as the main symptom. On the other hand, if the injury is unilateral, the following occurs hemianacusis. This, unlike cortical deafness, involves a hearing loss in only one ear.
2. Bilateral amygdala, huncus and hippocampus
If these three areas of the temporal lobe are injured bilaterally, they are together, the so-called “Klüver-Bucy Syndrome” appears.. This syndrome presents the following symptoms: hyperorality (non-stop talking), hypersexuality, passive and indifferent behavior, recklessness, difficulties in sustained attention and hypermetamorphosis (which is the impulsive tendency to touch objects).
3. Upper posterolateral area
If you injure that area, no matter what hemisphere it is, paracusis and auditory illusions appearas well as elementary auditory hallucinations (of simple sounds, such as a beep). Paracusis, on the other hand, are hearing disorders consisting of better hearing in noisy environments.
4. Left hemisphere
If the left hemisphere of the temporal lobe is injured, the following disorders appear: Wernicke’s aphasia (where the main symptom is a difficulty or impossibility to understand), verbal memory disorder (anterograde amnesia; that is, inability to record new memories), and complex auditory hallucinations (e.g., voices speaking to each other, voices addressing oneself, etc.).
5. Right Hemisphere
On the other hand, if the injury occurs in the right hemisphere, the following symptoms or disorders appear(as above), visual agnosia, spatial disorientation, and difficulty discriminating colors.
It is worth mentioning that the right hemisphere of the temporal lobe is related to the processing of primary emotions.