The brains of all mammals, including people, contain four lobes in the cortex, including the occipital, parietal, temporal, and temporal lobes frontal. The temporal lobe is located just below the lateral fissure and crosses both fissures of the brain
This vital structure helps process sensory information, including pain and auditory stimuli. It also helps to understand language, retain visual memories, and process and remember emotions.
Damage to this region of the brain can have global consequences for virtually every bodily function, since so much of what we do depends on emotions and sensory information.
Where are the temporal lobes located?
The temporal lobe is named for its proximity to the temples. It is located toward the base of the center of the cortex, just behind the temples. Like all other regions of the brain, it is not an independent organ. On the contrary, the temporal lobe interacts with and depends on all other regions of the brain, as well as on sensory information about the surrounding world. Thus, the temporal lobe-and the brain it supports-is a dynamic organ.
Rather than controlling the mind, it learns from the environment, creating a complex mind-body-environment interaction that constantly changes a person’s subjective experiences. Although all temporal lobes have a similar structure, the experiences that occur in each person’s temporal lobe are unique.
The most important areas of the temporal lobe
Limbic system
The temporal lobe is an important part of the limbic system. The limbic system is related to motivation, emotion, learning and memory.
Although the limbic system interacts with other areas of the brain, it works directly with the temporal lobe to influence the components of the limbic system.
The limbic system itself contains important structures, such as the amygdala and the hippocampus. These structures are responsible for key processes in the brain, such as memory, learning and attention.
The temporal lobe, which interacts with these structures, also plays a role in memory, helping to form long-term conscious memory.
Because of the connection with the limbic system, the temporal lobe contributes to a number of automatic states and bodily functions. This includes states of sexual arousal, anxiety levels and appetite, among others.
Broca’s area
Broca’s area is the region of the temporal lobe responsible for a person’s ability to speak and use language fluently.
Wernicke’s area
Wernicke’s area is a dominant temporal lobe region. It is responsible for processing and giving meaning to speech and the written word. Wernicke’s area helps a person understand speech and language.
What are the functions of the temporal lobe?
The temporal lobe is not an independent organ. It interacts directly with other regions of the brain and sends and receives signals to and from the spinal cord, allowing it to communicate with the entire body. Therefore, damage to the temporal lobe can affect the functioning of distant organs, and damage to organs completely unrelated to the temporal lobe can impede its ability to receive, process and respond to various signals.
Because the temporal lobe houses much of the limbic system, the temporal lobe is heavily influenced by and influences a number of automatic bodily functions, such as heart rate, arousal, anxiety, and similar states. Over time, alterations in these states can affect other bodily functions.
For example, early childhood trauma predisposes some people to a chronic state of anxiety that keeps them in a state of fight or flight. This floods the body with hormones such as cortisol, and can lead to chronic inflammation, and even health problems such as infertility.
As its position near the temples suggests, the temporal lobe plays a key role in auditory processing. This function includes perceiving sounds, assigning meaning to those sounds, and remembering them. Much of the temporal lobe’s auditory work is processed through the superior temporal gyrus, a structure in the temporal lobe that receives sound input directly from the ear. Some of its other functions include:
- The formation of visual memories, including long-term memories. Along with the amygdala and hippocampus, two limbic system structures, the temporal lobe is vital for the formation of conscious memories.
- Interpreting the meaning of visual stimuli, including object recognition. It is not enough to see an object. For vision to be useful, one must also understand what is being seen. The ventral part of the temporal lobe helps assign meaning to the images you see every day. Without the ventral lobe, you wouldn’t be able to recognize faces or read body language.
- Speech production. The temporal lobe contributes to speech production. Dysfunction of this area of the brain can lead to difficulty speaking, even when other structures are intact or you can consciously think about what you want to say.
- Speech recognition. The auditory cortex of the temporal lobe is key to hearing and understanding speech, but there are other structures in the temporal lobe that help understand and make meaning of language. Without the temporal lobe, we would not be able to name objects, remember verbal exchanges, or recognize language.
- Control unconscious and seemingly automatic reactions, such as appetite, thirst or hunger.
- Help the body maintain homeostasis. Note that this important function is shared by many brain regions.
Most common causes of temporal lesions
- The most common cause of temporal lobe lesions is stroke
- Space-occupying lesions can be primary brain tumors, benign (such as a meningioma) or malignant. They may also be secondary tumors or metastatic carcinoma, most often from lung or breast cancer.
- It may be a result of head trauma or surgical damage when a tumor is removed from that region. Head injuries often include extradural hematomas and contusion injuries (brain injury on the side opposite the point of impact). Surgery for intractable temporal lobe epilepsy is well established and will result in altered temporal lobe function.
- Progressive language impairment may be part of frontotemporal dementia. It presents earlier than Alzheimer’s disease and about 50% have a family history suggesting autosomal dominant inheritance.
- Encephalitis, especially herpes simplex encephalitis.
- Other pathologies such as multiple sclerosis may affect the temporal lobes, although this is a rare manifestation.
Possible consequences of temporal lobe lesions
Since the temporal lobe is involved in many bodily functions, damage to the temporal lobe can be catastrophic. Severe damage can lead to life-threatening hemorrhages, blood clots, and other conditions that can result in death if left untreated.
The prognosis associated with temporal lobe damage depends largely on the location of the damage, the origin of the damage, and prompt medical attention. For example, a person who seeks medical attention in response to a possible brain injury early may see less growth of that injury and, therefore, less temporal lobe damage. The quality of treatment, including occupational and speech therapy, as well as general health, diet, lifestyle and age also affect prognosis.
Ultimately, however, there is no way to predict the prognosis of a temporal lobe lesion with absolute certainty. The brain remains a mysterious organ, and there is much that is not well understood; some people, for example, remain able to speak even despite significant damage to Broca’s area, while others lose speech completely in response to minor damage. Likewise, some people recover spontaneously from severe temporal lobe damage, while others make little progress with treatment. There are exceptions to every rule, but your doctor is the best source of predictions about your injury, and a healthy lifestyle can only improve your prognosis.
The effects of temporal lobe lesions are myriad and can include
- Temporal lobe epilepsy: The most common form of epilepsy, and the most common cause of seizures, temporal lobe epilepsy produces uncontrolled electrical activity in the brain that can lead to seizures.
- Various forms of aphasia, a speech and language disorder. Damage to Broca’s area tends to impair the ability to speak, while damage to Wernicke’s area may impair the ability to understand speech.
- Memory impairment. The nature of the impairment depends on the location of the lesion, but the most common problems are difficulty in recognizing people, faces or objects; poor long-term memory; disturbances in autobiographical memory; and poor auditory memory.
- Personality changes, especially with regard to emotional regulation and interpersonal interactions.
- Changes in self-image and self-perception: Since the temporal lobe houses many of our memories, disturbances or loss of autobiographical memory can lead to changes in personality, as well as in a person’s sense of self.
- Changes in automatic behaviors, such as hunger, thirst, appetite and sexual desire. Some people with frontal lobe disorders develop addictions, inappropriate sexual behaviors, poor impulse control and aggression. Changes in appetite can be especially problematic, as both overeating and undereating can affect overall health, affecting brain function and aggravating pre-existing damage.
- Changes in executive function. Some people with temporal lobe damage have difficulty planning or coordinating their actions.
- Changes in navigation and spatial reasoning. Frontal lobe damage impairs memory, and spatial reasoning-including driving-depends heavily on memory. As a result, some people with temporal lobe damage may have difficulty driving, paying attention to physical cues, or navigating the world.
Disorders associated with the temporal lobe
The following is a brief description of some of the disorders that are often associated with lesions or changes in the temporal lobes
Dyslexia
There may be a relationship between dyslexia and the temporal lobe.
Dyslexia causes the person to have difficulty reading because the brain has trouble making meaning out of language. The person may have problems with word or sound recognition and may have difficulty matching certain sounds in language with their meanings.
People with dyslexia may have reduced activity in their left temporal lobes.
Wernicke’s aphasia
Wernicke’s aphasia, or receptive aphasia, affects a person’s ability to understand or use language. They may misuse words or speak in a way that does not make sense.
Wernicke’s aphasia usually occurs in people who have suffered a temporal lobe ischemic stroke.
Temporal lobe epilepsy
Temporal lobe epilepsy is one of the most common forms of partial epilepsy in adults, as noted in a study published in Imaging Brain Diseases. This disease causes uncontrolled electrical activity in the brain that can lead to seizures.
Pick’s disease
Pick’s disease, or frontotemporal dementia, is a less common form of dementia, which causes damage or atrophy in the frontal and temporal lobe.
The condition may include changes in states such as mood, attention levels, or irritable or aggressive behaviors.
A person with Pick’s disease may also lose the ability to use language properly. They may not be able to speak or recognize speech. They may also lose the ability to read or write and may experience a general loss of vocabulary.
Schizophrenia
There is a link between schizophrenia and a deficit or damage to the temporal lobe, within the primary auditory cortex in the left temporal lobe.
This condition can cause some of the main symptoms of schizophrenia, such as hearing external voices or other auditory hallucinations.
