Broca's area is one of the main areas of the cerebral cortex responsible for producing language. It is located in the third frontal gyrus of the left hemisphere, and corresponds to areas 44 and 45 of Brodmann: pars triangularis (Brodmann area 45) and the pars opercularis (Brodmann area 44). The Broca's area connects with the Wernicke area using a bundle of nerve fibers called an arcuate fascicle (or arcuate).
This region of the brain was first named in 1861 by the French neurosurgeon Paul Broca, who discovered the function of this area while examining the brains of patients with language difficulties. It was he who discovered that he plays a vital role in the generation of articulated speech.
- 1 Anatomical location of the Broca area
- 2 Drill area functions
- 3 Injuries in the Broca area
- 4 Drill Aphasia and Driving Aphasia
Anatomical location of the Broca area
As we have said, this area is located in the anterior area of the brain. Directionally, the Broca area is located in the lower portion of the left frontal lobe and controls the motor functions related to speech production.
Broca's area is divided into two subareas main: the triangular one (located in the previous part), which is responsible for the interpretation of various types of stimuli (plurimodal association) and the generation of verbal responses, and the opercular (located in the posterior area, next to the cortex motor), which deals with only one type of stimulus (unimodal association) and coordinate the organs of the phonatory apparatus for speech production.
Drill area functions
The Broca area is responsible for the following functions:
- Speech production
- Language processing
- Facial neuron control
Speech and language processing are two of the most complex functions of the brain. For this reason there are several areas of the brain that play a vital role in understanding speech and language. The Broca's area helps us accurately communicate our ideas to others through speech. She is also involved in the language comprehension.
Broca's area is connected to another area of brain language known as Wernicke's area through a group of nerve fiber bundles called an arcuate fascicle. The Wernicke area, located in the temporal lobe, processes both spoken and written language.
Another area of the brain associated with language is the so-called angular gyrus or angular gyrus. This area receives tactile sensory information from the parietal lobe, visual information from the occipital lobe and auditory information from the temporal lobe. Angular gyrus helps us use different types of sensory information to understand language.
For a long time it was assumed that the role of the Broca area was mainly dedicated to the production of language and not so much to the understanding of it. However, there is evidence to show that Broca's area also plays an important role in language comprehension. Patients with injuries in the Broca area show, among other symptoms, inability to correctly use the syntactic information to understand the meaning of the sentences. In addition, several neuroimaging studies have shown the involvement of the Broca area during the processing of complex sentences. Recently, in studies with functional magnetic resonance imaging (RMF) involving highly ambiguous sentences, it has been observed how the lower frontal gyrus is more activated. Thus, the level of activity in the lower frontal gyrus and the level of lexical ambiguity are directly proportional each other, due to the higher recovery demands associated with highly ambiguous content.
Apparently, there is a anatomical specialization in the area of Broca for language comprehension: the previous part is responsible for understanding the meaning of the words (semantics) and the back of the area is responsible for determining how the words sound (phonology).
Injuries in the Broca area
People with Broca area damage in the brain can understand language but cannot form words or speak fluently. This area, as we have said, is connected to another region of the brain known as the Wernicke area, which in turn is associated with processing and understanding of language.
However, the Broca area is not only responsible for issuing the language in a strictly motor sense. It seems to be also involved in the ability to understand grammar, even in its most complex aspects.
Injuries in the Broca area produce:
- Verbal fluency reduction, both in phonological and semantic tasks. For example, when a patient is asked to list words that begin with a particular letter or that belong to a category, those affected have trouble responding.
- Problems with alternating verbal fluency: For example, name two semantic categories alternately, such as animal names and city names.
- Language impoverishment: In extreme cases, mutism can be achieved, while in other cases it is characterized by hypolalia (decrease or delay in verbal expression), with reduction in verbal expression.
- Inability to understand the meaning of sayings or texts of greater complexity.
Drill Aphasia and Driving Aphasia
Damage to the Broca area also results in a condition called Broca's aphasia. People with Broca's aphasia have difficulties with speech production. His speech is slow and grammatically incorrect, consisting mainly of simple words. This people they understand language but have difficulty articulating and communicating their ideas verbally.
Access to vocabulary is very limited and the formation of sounds is often laborious and awkward. The person can understand speech relatively well and be able to read, but it should be limited in writing. Broca's aphasia is often referred to as a "non-fluid aphasia" due to the quality of hesitant and forceful voice.
Damage to the nerve fibers that connect Broca's area with Wernicke's area results in a condition called conduction aphasia. These people have difficulty repeating words or phrases correctly, but are able to understand language and speak coherently.