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Chapter 13 Language
Paul Broca and “Tan” In 1861, Broca examined a patient nicknamed “Tan,” after the syllable he said most often. The area of damage in Tan’s case is now known as “Broca’s area.”
Speech Production and Comprehension Aphasia: Difficulty in producing or comprehending speech Caused by brain damage Not produced by deafness of a simple motor deficit
Important Areas for Language
Speech Production Broca’s area: A region of frontal cortex, located just rostral to the base of the left primary motor cortex, that is necessary for speech production. a&um=1&sa=N&tab=wv#
Speech Production Broca’s aphasia (production aphasia): Speech of others understood, but … Their own speech is slow, labored, non- fluent Characterized by difficulty in articulation anomia agrammatism
Speech Production Function word: Content word:
Memory of Words: Anomic aphasia Anomic aphasia: Circumlocution:
Speech Comprehension Wernicke’s area: A region of auditory association cortex on the left temporal lobe of humans, which is important in the comprehension of words and the production of meaning speech. a&um=1&sa=N&tab=wv#q=wernickes%20aphasia&emb=0 a&um=1&sa=N&tab=wv#q=wernickes%20aphasia&emb=0 Wernicke’s aphasia: A form of aphasia characterized by poor speech comprehension and fluent but meaningless speech.
Broca’s and Wernicke’s Aphasia Damage to Wernicke’s area. Speech is fluent, but meaningless. Comprehension is very poor. Sound substitutions are common. Repetition is poor. Damage to Broca’s area. Speech is not fluent. Comprehension is affected, but good. Repetition is very poor.
Conduction Aphasia Damage to arcuate fasciculus. Speech production is good. Comprehension is good. Sound substitutions are common. Repetition is poor.
Global Aphasia Damage to Broca ’ s area, Wernicke ’ s area and the arcuate fasciculus. Abilities to speak, comprehend and repeat are impaired.
Transcortical Aphasia Transcortical motor aphasia: Difficulty producing speech. Good comprehension and repetition. Transcortical sensory aphasia: Speech production and repetition are good. Comprehension is poor.
The Wernicke-Geschwind Model of Aphasia
Alexia Patients with alexia are unable to read or to point to words and letters on command. Patients may write, but are unable to read what was written. Ability to recognize words spelled out loud is retained. Most cases result from damage to the left occipital cortex and the corpus callosum.
Agraphia Damage to motor areas responsible for fine movements, or: Inability to spell words: In phonological agraphia, patients can ’ t sound out words. can ’ t sound out nonsense words or new words can still write familiar words using visual imagery In orthographic agraphia, patients can ’ t form visual images of words to be spelled, but can spell phonetically.
Correlates of Dyslexia Less asymmetry in planum temporale Differences in the corpus callosum Prenatal testosterone and lateralization Dyslexia is more common among those who are left-handed or ambidextrous Dyslexia is more common among males Problems with phonological awareness, spatial relations, processing rapidly presented stimuli
Brain Activation During Reading Reader with dyslexia shows less activation of Wernicke’s area and the angular gyrus and more activation of Broca’s area.
Stuttering 1% of the population stutters. Stuttering may involve repetition or prolonging of speech sounds. 75% of stuttering people are male. Stuttering may be genetic. People who stutter may lateralize language to the right hemisphere; they show no impairments while singing. Treatments include reducing the rate of speech, reducing stress and providing auditory feedback.
Defining Intelligence Sternberg and Salter (1982): our ability to engage in “goal-directed adaptive behavior.” A more cynical view: intelligence is what intelligence tests measure.
Assessment of Intelligence Intelligence testing arose out of compulsory education laws. Binet and Simon proposed that bright children would act more like older children. Terman adapted Binet and Simon’s test for Americans. Current tests have abandoned the mental age concept.
General vs. Specific Abilities Charles Spearman suggested that all intelligence arises from a single general intelligence (g) factor. Howard Gardner proposed that we have multiple, independent types of intelligence. Savant behaviors Williams syndrome: low intelligence, but highly verbal
The Role of Heredity in Intelligence Highly debated topic. 60 – 80% of variation in intelligence may be due to heredity. Identical twins show.95 correlation in gray matter volume. “ Intelligence ” genes have been elusive. Thompson et al., 2001
Einstein’s Brain Zaidel (2001): Left hippocampal neurons were much larger than right hippocampal neurons. This asymmetry was not found in control subjects with normal intelligence. Witelson et al. (1999): Einstein’s parietal lobe was about 15% larger than normal.