Cognitive Neuroscience: Language Hemisphere and Aphasias

The Language Hemisphere

Notably, there exists a dogmatic assumption that the left hemisphere controls language. Nevertheless, this is a gross oversimplification of the matter. In this case, the two hemispheres are involved in language processing (Banich, 2004). However, the left hemisphere has a relative advantage of performing the role than the right hemisphere. This implies that the left hemisphere is well-positioned to process language and this often drives people to make a wrong assumption that it is the only hemisphere that controls language. It is important to note that even though the right and the left hemispheres of the brain are involved in language development, there exists an aspect of hemispheric specialization.

Moreover, despite the differences in chemical and anatomical structure in the hemispheres, they perform a lateralized function in language processing. The left hemisphere recognizes and processes language sequentially. Moreover, language processed follows the orthographic rules of grammar (Banich, 2004). However, it is highly adapted to enhance the learning of flexible and complex skills of any language.

Just like the right hemisphere, the left plays key roles in pictographic reading, semantic and syntactic functions. Notably, since the anatomical structures of the hemisphere are well adapted, it serves a leading role in language development and processing (Banich & Compton, 2011). On the other hand, the right hemisphere processes automatic language. Moreover, it assists in learning and comprehending speech. Recent studies have shown that the right hemisphere plays a significant role in reading (Banich & Compton, 2011). This is because it enables the interpretation of pictographic meanings of symbols and letters even though it is functionally more dormant than the left hemisphere (Banich & Compton, 2011).


Broca’s Aphasia is a type of aphasia that is caused by an impairment or damage to developmental issues in the anterior region of the brain. The disorder is named after Paul Broca who first diagnosed a patient suffering from the condition in the late 19th century (Banich & Compton, 2011). This disorder is also named “Broca’s Aphasia” since it affects the Broca’s region of the brain. It is described as non-fluent aphasia since it is characterized by a lack of fluency in speech especially when an individual is reading long sentences (Banich, 2004).

In this case, victims of this type of aphasia often omit small words such as ‘and’, ‘is’ and ‘the’. It occurs due to damages in the language output center. Wernicke’s Aphasia is a neurological disorder that results from impairment of the left part of the brain. The disorder affects Wernicke’s region of the cerebral hemisphere hence the name “Wernicke’s aphasia” (Banich & Compton, 2011). Additionally, it is thought that the disorder derived its name from Carl Wernicke a German psychiatrist and neurologist who hypothesized it in 1874. This region is also called the posterior, frontal lobe of the brain. Notably, the disorder is commonly known as fluency aphasia.

This is because individuals who suffer from this type of aphasia can read long sentences and often add new words in their speech fluency (Banich, 2004). However, they add new words in their speech, a situation that is often referred to as ‘word salad’. This makes their speech incomprehensible since they add unnecessary words to the sentences. The two types of aphasia are separate and distinct since they affect different parts of the brain. Additionally, they have dissimilar effects on the cerebral hemisphere. For instance, Broca’s aphasia interferes with speech fluency while Wernicke’s causes interruption of speech due to unnecessary wording (Banich & Compton, 2011).

Research has shown that there are numerous types of aphasia other than Broca’s and Wernicke’s. For instance, we have agrammatic aphasia, anomic aphasia, and conduction aphasia. Indeed, research has revealed that no treatment can effectively treat all the numerous types of aphasia. In this case, there is no universal treatment method since the disorder has dissimilar nature and presentations. This implies that there is no uniform identification for aphasia (Banich, 2004).

Therefore, it is arguable that each type should be handled independently from the others. Notably, the recommended treatment for aphasia aims to address language performance to improve task-specific skills. Practically, measures are employed to counter the spread of the disorder. Additionally, therapeutic interventions have been employed to raise the treatment intensity (Banich & Compton, 2011). These include visual communication therapy, visual action therapy, and functional communication treatment. Numerous forms of physical exercises have also been incorporated into treatment therapy techniques. It is imperative to mention that though treatment measures are not consistent, research has revealed that general therapies have positive effects on patients’ health.

What is the difference between retrograde and anterograde amnesia?

There are numerous types of amnesia that cause memory impairment. Commonly known types of amnesia include anterograde and retrograde. Anterograde amnesia is an impairment that interferes with the brain’s ability to learn new information (Banich, 2004). In this case, this type of amnesia inhibits a person’s ability to recall information learned after the onset of the impairment. Contrastingly, retrograde amnesia inhibits an individual’s ability to recall past experiences and information that was learned before the onset of amnesia.

What is the difference between Broca’s aphasia and Wernicke’s aphasia?

Broca’s Aphasia is a type of aphasia that is characterized by a lack of fluency in speech, especially where an individual is reading long sentences. In this case, victims of this type of aphasia often omit small words such as and, is, and the (Banich, 2004). It occurs due to damages in the language output center. On the other hand, Wernicke’s Aphasia occurs due to damages in the posterior, frontal lobe of the brain (Banich & Compton, 2011). Nevertheless, individuals who suffer from this type of aphasia can read long sentences and often add new words in their speech.

When describing language deficits, what is “word salad”?

This is a concept that is used to describe speech output that occurs among individuals suffering from Wernicke’s aphasia. In this case, individuals produce speech without hesitating but they incorporate new words in their sentences (Banich, 2004). However, their speech appears like a jumble of words randomly mixed. In this case, this is a psychological disorder that affects language and it is commonly known as schizophrenia. Notably, “word salad” occurs involuntarily hence producing an incoherent speech.

What is the difference between syntax and semantics?

Language is composed of both syntax and semantics. However, the two are different since syntax has more to do with grammar while semantics is all about grammatical meaning. It is imperative to note that syntax denotes the arrangement of words in a sentence (Banich, 2004). In this case, it governs the rules of grammar such as proper sentence structure and speech. Syntax strictly deals with grammatically correct sentences. Contrastingly semantics deals with an individual’s interpretation of a sentence and its meaning. In this case, one ought to have prior knowledge of the language involved to interpret the meaning in a sentence (Banich & Compton, 2011).

What is Agrammatic aphasia?

This is a type of aphasia that that is characterized by failure to produce grammatically correct speech. Individuals with this aphasia produce unique speech that is full of grammatical errors due to omission of words (Banich, 2004). Nevertheless, symptoms of the disorder vary from one person to the other depending on the severity level. This disorder occurs due to the disruption of the phonematic representation of speech sounds in the brain (Banich & Compton, 2011).

How are the hippocampus and amygdala involved in memory?

Hippocampus and amygdala are vital tools in memory since they reinforce each other to process information. For instance, the hippocampus is functional when it comes to encoding new information from working memory to long-term memory for permanent storage (Banich, 2004). Moreover, it helps in consolidating the information in the long-term register over time. On the other hand, amygdale synthesizes the emotional meaning of a stimulus before it is taken to the hippocampus for encoding and consolidation (Banich & Compton, 2011).

What is Korsakoff’s syndrome? How is it caused?

Korsakoff’s syndrome is a neurological impairment that occurs due to the insufficiency of thiamine in the brain. This disorder is said to cause numerous types of amnesia such as anterograde and retrograde. Therefore, victims of this disorder suffer from the poor insight and memory loss (Banich & Compton, 2011). When brains lack sufficient thiamine, the medial thalamus tissues get damaged. This condition is said to occur due to excess alcoholism and severe malnutrition.

How are the central executive, phonological loop, and visuospatial sketchpad involved in memory?

Research has shown that the central executive initiated the recall of memories from the long-term memory bank. Therefore, it is important in making plans for future actions and the integration of new information (Banich, 2004). Moreover, it aids one to recall rules and facts while solving mathematic problems Phonological loop, on the other hand, acts as a speech and sound component that holds auditory and verbal information in the working memory. It temporarily stores information in the working memory before it is coded into long-term memory.

What is the difference between procedural and declarative memory? Which is most likely to be spared in someone with amnesia?

Declarative memory is a memory that stores facts that are encountered repetitively. These facts are commonly used and entail the use of basic knowledge. Contrastingly, procedural memory is used to recall sequential events that occur on a routine basis. Notably, this memory helps people to get the procedure to perform certain tasks. However, the basic difference is based on how they get affected when the brain gets damaged (Banich & Compton, 2011). Research has shown that there is no significant effect on procedural memory as compared to declarative memory when an individual suffers from amnesia. In this case, procedural memory will be spared at the expense of declarative memory.

What is long-term potentiation (LTP) and how is it involved in memory?

Long-term potentiation is referred to as a long-lasting enhancement that exists between neurons where signal transmission occurs This occurs due to an increase of stimulation frequency in the neurons, a factor that increases synaptic strength(Banich, 2004). It serves the purpose of prioritizing incoming signals in the brain. However, LTP is not the key to human memory but it helps to speed the retrieval of critical memories.


Banich, M. (2004). Cognitive neuroscience and neuropsychology. Boston: Houghton Mifflin Co.

Banich, M. (2011). Cognitive Neuroscience. Belmont: Wadsworth Publishing, Inc.