Tag Archives: Broca’s Aphasia

Tongue Twisters and Communication: How the Brain Learns Languages

Have you ever wondered how the brain learns languages? Why are we able to communicate so easily? How is it that we can formulate sentences, speak, and comprehend what others are saying in split-seconds? A majority of us think that language is only controlled by our lips, mouths, ears, and hands. However, what most people don’t know is that language originates in the brain. Specifically, our language faculties are located in certain areas of the left hemisphere cortex in healthy adults. A fun fact to know is that the science of neurolinguistics studies the physical structure of the brain as it relates to language production and comprehension. Read more to find out how the brain learns languages!

How the Brain Learns Language

Some scientists have argued that language is what distinguishes humans from all other animals on the planet. Other scholars ask if humans are really the only species to possess language. Of course, other animals communicate with one another, like bees, who send each other messages through their special dances. However, human language is more than just communication. Rather, it is a complex system of brain processing that involves auditory messages used as symbols to convey meaning and function in this complicated world.

Looking Deeper into the Structure of the Human Brain

When discussing the brain as a language organ, some physiological and structural characteristics of our brain must be understood:

  1. Human brains have a contralateral neural control arrangement – this means that the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.
  2. Each hemisphere has somewhat unique functions, making them asymmetrical. For example, the right hemisphere controls spacial perception, while the left hemisphere controls abstract reasoning and physical tasks that require a step-by-step progression. The left hemisphere is also responsible for language control, which takes place inside the perisylvian area, and this ability is usually fully developed by the time we reach the age of puberty.

Now, why does language originate from the left hemisphere rather than the right? Since the left hemisphere controls patterns that progress step-by-step in a single dimension, it is more apt to control language than the right, which performs complex multi-step tasks. Language is a linear process – sounds and words are uttered one after another in a definite progression, not in multiple directions all at once. In neurolinguistics, this is called monolineal progression. Evidence that language is activated by the left hemisphere comes from PET scans and studies on individuals who suffer from brain injuries.

How the Brain Learns Languages

According to Noam Chomsky, a famous linguist of the late twentieth century, we are all born with a language instinct or language acquisition device (LAD). This is our innate capacity to acquire an extremely creative system of communicating with each other. It seems to be a human genetic trend that everyone possesses: nearly all children exposed to language naturally acquire it as if by magic. Most researchers believe that the LAD is the result of a complex interaction of many genes in the brain that work together to produce and interpret language.

However, it must be noted that the natural ability for humans to acquire language normally diminishes near the age of puberty, which is known as the critical age for fluently acquiring a native tongue. Researchers believe that this phenomenon is connected with the lateralization of language in the left hemisphere. Studies show that children actually use both left and right hemispheres to process language because these brain areas are undeveloped for the time. As children age, their brain structures mature, whereupon the responsibility of language is shifted fully to the left side of the brain. If individuals lose the chance to learn language during their early years before adolescence, then their hemispheres miss the opportunity to mature and develop correctly. Therefore, people who are not exposed to proper language communication during childhood usually are unable to learn to speak a language fluently in adolescence and adulthood. A real-life example of this is the story of Genie Wiley, a feral child who was locked in her dark bedroom for the first thirteen years of her life, tortured by her parents. Because she was not exposed to any form of direct language communication, when she was found at age 13, she was unable to learn language and speak fluently. Her overall abuse resulted in severe consequences that affected her overall ability to interact with others later in life.

See more about the Genie Wiley case below

Aphasias

Injuries of specific parts of the left hemisphere responsible for language acquisition can result in aphasias, or speak impairments. This is caused by damage in the region of the sylvian fissure, in the perisylvian area. The following two types of language loss are associated with harm done to particular sub-regions of the perisylvian area:

1. Broca’s Aphasia

In 1861, Paul Broca discovered Broca’s area, which is located in the frontal portion of the left perisylvian area. This seems to be involved in grammatical processing, specifically concepts like singular vs. plural and tenses. It processes the grammatical structure of sentences rather than the specific units of meaning – instead of focusing on the content of the language, it emphasizes on how words are put together. Broca’s Aphasia involves a difficulty in speaking, whereby it is also known as emissive aphasia. Broca’s aphasics are able to comprehend written and spoken language but have great difficulty in responding in any coherent way. They tend to utter only isolated words without using conjunctions or full sentences to relay their thoughts.

2. Wernicke’s Aphasia

In 1875, Karl Wernicke discovered Wernicke’s area, which is found in the lower posterior part of the perisylvian region. This controls comprehension, as well as the selection of content words. If this area becomes damaged, grammar and function words are preserved, but the content is mostly destroyed. Therefore, Wernicke’s aphasia involves a difficulty in comprehension – people afflicted are unable to extract meaning from language. It’s also known as receptive aphasia because these people are unable to respond at all to those they are conversing with (contrast with Broca’s aphasia, where patients can understand but have difficulty in replying). Wernicke’s aphasics tend to speak incessantly and will utter volumes of grammatically correct nonsense with relatively few content words or with jibberish words like “thingamajig” or “whatchamacallit,” instead of real content words.

More on How the Brain Learns Language

The healthy human brain uses both areas in unison while speaking and processing language. Adults use the neurons of Wernicke’s area to select sounds to listen to, and the neurons of Broca’s area combine these units according to phonology and syntax to produce utterances.

To speak a word that is written on paper (i.e. reading aloud), information first goes to the primary visual cortex. From there, the information is transmitted to the posterior speech area, including Wernicke’s area. From Wernicke’s area, information travels to Broca’s area, and then to the primary motor cortex, whereupon we speak aloud the words we have comprehended from paper. This similar pathway is utilized when we want to repeat words that are heard, but in this situation, information first goes to the primary auditory cortex and then to the posterior speech area.

What Happens When Your Brain Learns A New Language?

According to recent research by Swedish scientists using magnetic resonance imaging (MRI) and electrophysiology on lab participants, learning a foreign language can increase the size of your brain. Young adult military recruits learned Arabic, Russian, or Dari intensively, while a control group of medical students studied hard on their sciences without learning any new language. The MRI scans showed that specific parts of the brains of the language students developed in size, whereas the brain structures of the control group remained unchanged. The areas of the brain that grew were linked to how easy the learners found the languages, and brain development varied according to performance. Some learners increased the sizes of their hippocampus, while others had an increase in size of the motor region of their cerebral cortex.

Although the implications of this research are not very clear as of yet, they might eventually lead to advances in the use of technology for second-language learners. For example, other researches have used the same ultrasound machinery employed during pregnancy sonograms to explain to language learners how to make sounds by showing them visual images of how their tongue, lips, and jaw should move with their airstream mechanisms and the rise and fall of the soft palate.

Other research, done by Kara Morgan-Short at the University of Illinois at Chicago, used electrophysiology to examine how the brain learns language. She taught second-language learners to speak an artificial language. One group learned through explanations of the rules of the language, and the second group learned by being immersed in the language. While all of the participants learned something from each artificial language, it was the immersed learners who had brain processes like those of native speakers.

Brain imaging research might eventually allow us to shape language learning methods to our cognitive abilities. It can possibly tell us whether we learn best from formal instructions that highlight rules, immersing ourselves in the sounds of the language, or maybe one followed by the other.

Sources: 1, 2, 3

Frontal Lobe: Areas, functions and disorders related to it

The brain is divided into four lobes, differentiated by their location and functions. In this article, we are going to focus on one of the lobes: the frontal lobe. The frontal lobe is the biggest lobe in the brain and the most important lobe for the human species. 

Why is the frontal lobe so relevant? What are its functions? The following article will give you an all-inclusive look on the frontal lobe. 

Frontal lobe

Frontal Lobe: Anatomy and Functions

The Frontal lobe is located at the front of the brain, at the front of each cerebral hemisphere and in front of the parietal lobe. It is considered the most important lobe due to its functions and because it takes up one-third of the total brain. In other species its volume is inferior (chimpanzees 17% and dogs 7%).

The functions of the frontal lobe depend on the area we focus on. It plays a part on movement control as well as in high-level mental functions or behavior and emotional control. The frontal lobe is divided into two main areas: the motor cortex and the prefrontal cortex.

Motor cortex in the frontal lobe

The main function of the motor cortex is to control voluntary movement, including the ones in expressive language, writing, and ocular movement. This cortex is divided into three areas:

Primary Motor Cortex

Sends commands to the neurons in the brain stems and spinal cord. These neurons are in charge of specific voluntary movements. Inside the primary motor cortex, of both hemispheres, there is a representation of the contralateral half of the body. That is, in each hemisphere, there is a representation of the opposite side of the body.This is known as the motor homunculus and it is inverted, therefore the head is represented at the bottom.

Premotor Cortex

This area is in control of the preparation and movement programming. Premotor cortex automates, harmonizes and archives movement programs related to previous experiences. Within the premotor cortex:

  • Supplementary motor area: in charge of controlling postural stability during stance or walking.
  • Ocular field: controls the joint deviation of the gaze when voluntary exploring a field.
Broca’s Area

It’s considered the center for producing speech, writing, and also in language processing and comprehension. It coordinates movements of the mouth, larynx and respiratory organs that control language expression. Injuries can produce different language disorders. 

Prefrontal Cortex of the Front lobe

The prefrontal cortex is located in the front part of the frontal lobe. It is considered the ultimate expression of human brain development. It is responsible for cognition, behavior and emotional activity. Prefrontal cortex receives information from the limbic system (involved in emotional control) and acts as a mediator between cognition and feelings through executive functions. Executive functions are a set of cognitive skills necessary for controlling and self-regulating your behavior. Within the prefrontal cortex, three areas or circuits are important: dorsolateral, anterior and orbital cingulum.

Dorsolateral area of the frontal lobe

It is one of the most recently evolved parts of the human brain. It establishes connections with the other three brain areas and transforms the information into thoughts, decisions, plans, and actions. It is in charge of superior cognitive abilities such as:

  • Attention: Focus, inhibition, and divided attention.
  • Working memory: maintenance and manipulation of the information.
  • Short-term memory: ordering events.
  • Prospective memory: programming upcoming actions.
  • Hypothesis generator: analysis of the possible outcomes.
  • Metacognition: self-analysis of cognitive activity and continuous performance.
  • Problem Resolution: analysis of the situation and development of an action plan.
  • Shifting: the ability to adapt to new situations.
  • Planning: organizing behavior towards a new objective.

General Cognitive Assessment Battery from CogniFit: Study brain function and complete a comprehensive online screening. Precisely evaluate a wide range of abilities and detect cognitive well-being (high-moderate-low). Identify strengths and weaknesses in the areas of memory, concentration/attention, executive functions, planning, and coordination.

Anterior cingulum of the frontal lobe

This area regulates motivational processes. It’s also in charge of perceiving and resolving conflicts as well as regulating sustained attention.

Orbital area of the frontal lobe

This area is in charge of controlling emotion and social conduct. It regulates emotional processing, controls behaviors based on context and detects beneficial or detrimental change.

A neuroscientist explains the frontal lobe and the types of disorders that can happen after an injury.

Frontal Lobe: Disorders related to it

As we have explained, the frontal lobe is involved in different processes (motors, cognitive, emotional and behavioral). This is why disorders due to injuries suffered to this area can vary from concussion symptoms to others more severe.

Motor disorders

Injuries to the primary or premotor cortex can cause difficulties in the velocity, execution and movement coordination, all leading to different types of apraxia. Apraxia is a disorder in which the individual has difficulty with the motor planning to perform tasks or movements when asked, provided that the request or command is understood and he/she is willing to perform the task. A University of Toronto scientist has discovered the brain’s frontal lobe is involved in pain transmission to the spine. If his findings in animals bear out in people, the discovery could lead to a new class of non-addictive painkillers.

  • Ideomotor apraxia: Deficits or difficulty in their ability to plan or complete previously learned motor actions, especially those that need an instrument or prop. They are able to explain how to perform an action but can’t act out a movement.
  • Limb-kinetic apraxia: voluntary movements of extremities are impaired. For example, they can’t use their fingers in a coordinated fashion (waving).
  • Buccofacial or orofacial apraxia: Difficulty carrying out movements of the face, tongue, mouth, cheeks, etc. on demand.

Apart from the apraxias, other disorders can be developed from injuries to the frontal lobe, such as language disorders or aphasias.

  • Transcortical Motor Aphasia: language disorder due to which the person has a lack of verbal fluency (slow speech with reduced content and poorly organized), limited spontaneous language (lack of initiative) and difficulty or incapacity in writing.
  • Broca’s Aphasia: language disorder that generates a lack of verbal fluency, anomia (inability to access the lexicon to evoke words), poor syntactic construction in speech, difficulties in repetition, reading and writing.

Dysexecutive syndrome

It consists of a group of symptoms, cognitive, behavioral and emotional that tend to happen together. However, the symptoms are going to depend on the injured area:

Dorsolateral Area

An injury in this area is usually related to cognitive problems such as:

  1. Inability to solve complex problems: decrease in fluid intelligence (reasoning, adapting and resolving of new situations, etc.).
  2. Cognitive rigidity and perseveration: the person maintains a thought or action despite being invited to change it.
  3. Decreased learning ability: difficulty in acquiring and maintaining new learning.
  4. Temporal memory impairment: deficit in the order things happened
  5. Deficiency in motor programming and changing motor activities: difficulties in the organization of sequences of movements and the time to change an activity.
  6. A decrease in verbal fluidity: impairment in the ability to recall words after an instruction. This action not only requires the lexical part but also organization, planning, focus and selective attention.
  7. Attention Deficit: difficulty maintaining your attention and inhibiting other irrelevant stimuli or changing the focus of attention.
  8. Pseudo-depressive disorders: similar symptoms to depression (sadness, apathy, etc.).
Anterior cingulum area
  1. Reduction of spontaneous activity: appear to be static.
  2. A loss in initiative and motivation: noticeable apathy.
  3. Alexithymia: difficulty identifying emotions and therefore inability in expressing own emotions.
  4. Language restriction: answers tend to be monosyllabic.
  5. Difficulty in controlling interference: selective attention impairment.
  6. Pseudo-depressive disorders. 
Orbital area

The symptoms of an injury in this area are more behavioral. The person’s behavior tends to be uninhibited.

  1. Changes in personality: high instability between who he is and how he acts. Similar to what happened to Phineas Gage. 
  2. Irritability and aggressiveness: exaggerated emotional reactions in daily life situations.
  3. Echopraxia: imitation of observed movements in others.
  4. Disinhibition and impulsivity: lack of self-control over their behavior.
  5. Difficulty adapting to social norms and rules: behaves socially unacceptable.
  6. Judgment is impaired: many reasoning errors.
  7. Lack of empathy: difficulty understanding other people’s feelings.
  8. Euphoria
 The frontal lobe is incredibly important for humans to function to their full potential. Even without brain injury, it’s crucial to maintain our cognitive skills active. CogniFit offers a complete assessment of your cognitive skills and brain training not only as a rehabilitation due to injury, dementia, etc. but it can also strengthen your current neural patterns. Brain health is essential to lead a full life.
Hope you liked this article, feel free to leave a message below!
This article is originally in Spanish written by Natalia Pasquin Mora, translated by Alejandra Salazar.