This area of the brain has important functions in different areas of cognition and language.
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 symptoms caused by the different lesions, depending on the area of the lobe affected.
- We recommend you read: “Human brain: its main parts and functions”
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 of them specialized in a certain function or task: these are hearing, memory, comprehensive languageand smell, among others. Later we will know the different functions of the temporal lobe.
It is the second largest structure of the cerebral cortex (the first is the frontal lobe).
In the cerebral cortex we find, in fact, two temporal lobes: one that is located in the left hemisphere, and another in the right hemisphere. The fissure of Silvius is the structure that divides these two lobes.
The temporal lobe is the lobe that establishes the most connections with the limbic system, a systemrelated to emotions, pleasure and memory, among others.
Anatomy
The temporal lobe occupies about a quarter of the cerebral cortex. Anatomically, where is the temporal lobe located, more concretely? It is located in front of theoccipital lobe (the lobe responsible for vision), that is, behind the temples. Thus, it is located on the lower side of the brain (very close to the ears).
With what does it delimit this lobe? By the upper region, the temporal lobe “attaches” to the parietal lobe (borders on it); On the other hand, by the posterior region, it “attaches” to the occipital lobe, and by the anterior region, to thefrontal lobe.
On the other hand, we can divide the temporal lobe into “three large zones”: one of them, related to object recognition; another, with long-term memory, and another with auditory information processing.
Functions
What functions is the temporal lobe involved in? We will talk about the seven most prominent and relevant below.
1. Face and object recognition
This function is located in the visual cortex of the temporal lobe. This cortex also allows to categorize the different visual stimulithat occur in the environment.
2. Language development
The main structure of the temporal lobe involved inlanguage development is the supramarginal gyrus, a small structure located in the tertiary sensory area.
3. Key role in hearing
In this lobe is the primary auditory cortex, responsible for processing auditory information. As we will see later, lesions in the temporal lobe involve alterations in auditory processes. That is why this lobe is considered the “auditory lobe” par excellence.
4. Execution of the memory
It has a key role in auditory memory, but also in others (especially the hippocampus).
On the other hand, the temporal lobe has a key role in declarative memory (that is, the conscious memory of experiences); Specifically, the medial temporal lobe develops this function, formed by the following structures: hippocampal region, perirhinal cortex, entorhinal cortex and parahippocampal cortex. These structures also connect with the cerebral cortex, allowing memory processes.
5. Establishment of body balance
Another function with which the temporal lobe is related isthe regulation and establishment of body balance. In addition, balance is also related to ear structures.
6. Regulation of emotions
The main arearelated to the regulation of emotions in the temporal lobe is the association area 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 motivational processes, as well as in the regulation of emotions or states such as pleasure, anger and anxiety.
Lesions
What happens if the temporal lobe is injured? It all depends on the injured area. The symptoms are especially related to memory disorders, hearing disorders and visual disturbances.
1. Bilateral superior temporal gyrus
If this area is injured, two things can happen: that the injury is bilateral (that is, that it occurs in both cerebral hemispheres) or that it is unilateral (that it occurs in a single 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).
Thus, in the event that the lesion is bilateral, cortical deafness occurs. Cortical deafness causes as a main symptom a loss of hearing (in both ears). On the other hand, if the lesion is unilateral,hemianacusis occurs. This, unlike cortical deafness, involves hearing loss in only one ear.
2. Bilateral tonsil, huncus and hippocampus
If these three areas of the temporal lobe, which are joint, are injured bilaterally, the so-called “Klüver-Bucy Syndrome” appears. This syndrome presents the following symptoms: hyperorality (talking non-stop), 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 this area is injured, whatever the hemisphere, auditory paraacusis and illusions appear, as well as elementary auditory hallucinations (of simple sounds, such as a beep). On the other hand, paracusises are hearing disorders consisting of hearing better 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 difficulty or inability to understand), verbal memory disorder (anterograde amnesia; that is, inability to record new memories) and complex auditory hallucinations (e.g. voices talking 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: perceptual amusia, nonverbal memory disorder (as in the previous case), 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.
References
- Carslon, N.R. (2005). Physiology of behavior. Madrid: Pearson Education.
- Junqué, C. & Barroso, J. (2009). Manual of Neuropsychology. Madrid. Synthesis Psychology.
- Kolb, B. and Whishaw, I.Q. (2006): Human Neuropsychology. Pan American Physician.
- Netter, F. (1989). Nervous system. Anatomy and physiology. Barcelona: Salvat.
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