Biology of Language: Brain Mechanisms and Impairments

Comprehensive practice flashcards covering brain mechanisms of language, types of aphasia, reading disorders, and specific anatomical regions discussed in the lecture.

Broca’s area

A region of frontal cortex, located just at the front of the base of the left primary motor cortex, that is necessary for normal speech production.

Wernicke’s area

A region of auditory association cortex on the left temporal lobe important in the comprehension of words and the production of meaningful speech.

Lateralization (Speech Dominance)

The left hemisphere is dominant for speech in $90$ percent of the population. Right-hemisphere dominance is seen in $4$ percent of right-handed people, $15$ percent of ambidextrous people, and $27$ percent of left-handed people.

Broca’s aphasia

A disorder caused by damage to the inferior left frontal lobe and underlying subcortical white matter, characterized by slow, laborious, non-fluent speech, but relatively intact comprehension.

Agrammatism

A symptom of Broca's aphasia involving difficulty comprehending or employing grammatical devices, such as verb endings and word order, and difficulty producing function words (e.g., a, the).

Content words

Words that convey meaning, such as apple, house, or throw, which patients with agrammatism are still able to say.

Wernicke’s aphasia

A condition resulting from damage to both Wernicke’s area and the posterior language area, characterized by poor speech comprehension and fluent but meaningless speech.

Pure word deafness

The inability to comprehend the meaning of speech despite the ability to hear, speak, and usually read and write, caused by damage to Wernicke’s area or its auditory input.

Transcortical sensory aphasia

A speech disorder caused by damage to the posterior language area where a person can repeat speech they hear but cannot comprehend its meaning or produce meaningful spontaneous speech.

Posterior language area

The region surrounding the posterior part of the lateral fissure near the junction of the temporal, occipital, and parietal lobes that interchanges information between recognition and comprehension areas.

Conduction aphasia

An aphasia characterized by the inability to repeat words precisely while maintaining the ability to speak normally and comprehend the speech of others.

Arcuate fasciculus

A fiber bundle connecting Wernicke’s area and Broca's area; damage to this direct pathway is expected to produce conduction aphasia.

Pure Alexia (Pure word blindness)

The loss of the ability to read without the loss of the ability to write, produced by lesions in the visual cortex of the left occipital lobe and the posterior end of the corpus callosum.

Visual Word-Form Area (VWFA)

A region of the left fusiform gyrus at the base of the temporal lobe essential for the ability to recognize words as a whole.

Whole-word reading

A process of reading by recognizing a word as a whole, also known as sight reading.

Phonetic reading

A process of reading by decoding the phonetic significance of letter strings, also known as sound reading.

Surface dyslexia

A reading disorder where a person can read phonetically (sounding out words) but has difficulty reading irregularly spelled words (e.g., Yacht) by the whole-word method.

Phonological dyslexia

A reading disorder where a person can read familiar whole words even with irregular spellings but cannot read unfamiliar words or pronounceable non-words (e.g., Glab).

Temporoparietal cortex

The region of the parietal cortex involved in phonetic reading that processes the sounds associated with letters or symbols.

Function words

Words with grammatical utility such as 'a', 'the', 'some', 'in', 'about', and 'but' which are difficult for patients with agrammatism to produce.