Chapter 19: Language and Hemispheric Assymetry Flashcards
Define communication:
Transmission of information between individuals
Define Language:
A highly specialized form of communication in which arbitrary symbols or behaviors are assembled and reassembled in almost infinite variety and associated with a vast range of things, actions, and concepts
Define Grammer:
The set of rules for a given language
Define Phonemes:
Basic speech sounds of a language
Define Morphemes:
Combinations of phonemes into a simple unit of meaning. example: Unfathomable contains the morphemes; un-. fathom, -able.
Define Semantics:
Combination of morphemes into words which have meaning.
Define Syntax:
Rules for constructing a meaningful string of morphemes (complete sentences or phrases); an element of grammar.
What language develops a baby’s language skills in early development?
Parantese: The singsong speech that parents universially use with babies. The lilting qualities of parentese convey emotional tone and reward
What is important to note in the development of language?
Language acquisition has a critical/sensitive period.
Cases of restored hearing and isolation where speech was not recovered yields evidence for this.
It’s also easier for children to acquire language before age 11. after age 11 different brain regions are used for different languages.
Which function does hand movement serve in speech?
Hand movements facilitate speech. When prevented from making gestures more slipups and pauses occur.
People blind from birth also make hand gestures when they speak.
Sign language will occur in deaf people even without access to another language.
What role does the FOXP2 gene play?
It’s important for the normal acquisition of language.
A specific mutation in FOXP2 slows the learning of speech down considerably in children, who also will suffer long-lasting difficulties with certain language tasks
What kind of gene is FOXP2?
Regulatory gene: It produces protein which controls the expression of a number of other genes (transcription factor), affecting the growth and interconnection of neurons during development.
mutation in three genes are connected to stuttering, which genes? and what roles do they play?
GNPTAB, GNPTG, and NAGPA play a part in the normal functioning of lysosomes, organelles involved in breakdown of cellular waste materials.
Animals also show vocal learning and produce vocalizations to transfer information. What is the interesting biological parallel with humans in this regard?
Studies with mice have shown that their ultrasonic vocalizations are impaired when their Foxp2 gene is mutated.
Studies with Birds show that silenced Foxp2 expression in Nucleus “x” of paraolfactory lobe led to learning difficulties of singing. The birds made errors reminiscent of human errors.
Male birds learn to sing similar to the fashion humans learn speech. What are the three steps birds go through?
- Exposure from another male tutor (usually a father)
- Trial and error period. Bird makes successive approximations of a stored model
- Crystallization of the song
What is the syrinx? and can you describe the two pathways used to control it?
Syrinx is the vocal organ of the bird.
- The direct pathway which goes from the high vocal center (HVC) -> nucleus robustus of the archistriatum (RA) -> Brainstem nucleus of the twelfth cranial nerve (n XII -> syrinx.
- The long pathway starts at HVC -> Nucleus “X” in paraolfactory lobe -> Medial dorsolateral nucleus of the thalamus (DLM) -> Lateral magnocellar nucleus of the anterior neostriatum (LMAN) -> RA -> n XII -> syrinx
Do only male birds sing?
Yes but there are exceptions. Female birds memorise their fathers song for future selct of mates.
Songbird species like the plain-tailed wren both male and female sing duets.
What is the wada test?
Injecting a hemisphere with anesthetic sodium amytal which temporarily shuts down the hemisphere for a few minutes. During the shutdown different behavioral tests are administered to determine hemispherical specialization.
Name the structures important for both speech production and comprehension.
Broca’s area, Primary motor cortex, Primary auditory cortex, Supramarginal gyrus, Angular gyrus, and Wernicke’s area
What is Paraphasia?
Insertion of incorrect sounds or words in speech production
What is neologisms?
Nonsense words
What is Apraxia?
A motor impairment characterized by great difficulties in executing a sequence of movements that is not related to weakness, paralysis, lack of coordination, or any kind of sensory problems
Which five aphasia do the authors mention?
- Nonfluent (Broca’s) Aphasia
- Fluent (Wernicke’s) Aphasia
- Global Apahasia
- Conduction Aphasia
- Subcortical Aphasia.
Describe Nonfluent (Broca’s) Aphasia
Language impairment, caused by lesions in Broca’s area, characterized by difficulty in speech production
Often patients also suffer from hemiplegia, paralysis of one side of the body, because primary and supplementary motor cortex are in proximity to Broca’s area
Describe Fluent (Wernicke’s) Aphasia
Language impairment characterized by fluent, but meaningless, speech and missing comprehension of language.
Word deafness (unable to understand speech) stems from superior temporal lobe damage. Word blindness (unable to understrand written speech) stems from damage to angular gyrus.
Describe Global Aphasia
An aphasia where patients can neither understand nor produce language.
Describe Conduction Aphasia
A Lesion of the arcuate fasciculus which disrupts transfer of information from Wernicke’s to Broca’s.
What are the two conflicting theories of motor control and language?
Can you shortly describe them?
Traditional connectionist model and the motor theory of language
Connectionist model is selfexplanatory
The motor theory of language is a seemingly modular theory
How do we repeat a heard word?
According to connectionist model the sounds are processed in primary auditory cortex then it’s transmitted to Wernicke’s area, which determines what word was said. Wernicke’s are the transmits this to Broca’s which forms a motor plan which is transmitted to primary motor cortex for execution.
How do we repeat a written word?
According to a connectionist model primary visual cortex analyzes the image and transmits it to the angular gyrus which then, after decoding information and recognizing the word associated with the visual form, sends it to Wernicke’s area. Wernicke associates the word with it’s spoken form and transmits this to Broca’s area which forms a motor plan that is send to primary motor cortex for execution
What usually causes dyslexia, besides lesions in the left hemisphere?
anomalies in arrangement of cortical neurons in frontal and temporal lobe. It is theorized that this is caused by defective neuronal migration, cells migrating into the cerebral cortex, in fetal development. Results in excessive cortical folding (micropolygyria) and nests of extra cells (ectopias).
Developmental dyslexia has a genetic component. Which genes are implicated?
Finish studies has found two genes DYX1 and ROBO1 which has been linked to reading disorders.
Other studies found DCDC2, which is believed to participate in the migration of neurons towards their positions in the cortex, predicting reading performance in a large analysis of families.
KIAA0319 was found to cause the cortical ectopias observed in humans with dyslexia
Electrical stimulation and TMS can map the cortical surface. Focusing on TMS; two locations interrupt different functions of production
Subregions in Broca’s.
Anterior and ventral division attributed importance for semantic meaning of words.
Posterior subregion associated with phonological processing.
Supermarginal gyrus is involved in both semantiv and phonological aspects of language
What sort of studies are most prevalent in lateralization?
Studies using split-brain patients
What are the biggest finds in lateralization or specialization?
Identifying language through various modalities is strongest in the left hemisphere or the right sensory field (contra-lateral field).
The right hemisphere is dominant in processing spatial information, prosody (emotional tone of voice), and other tasks
What spatial information processing is the right hemisphere particularly important for?
Recognizing faces
Recognizing objects.
Lesions to what region is usually involved in prosopagnosia (inability to recognize faces)
The fusiform gyrus
It can also be caused developmentally
