MCB 170: Language

What is the definition of language?

the system of words and symbols that humans use to communicate ideas, thoughts, and feelings

What is the definition of speech?

the way that humans produce sounds in the words that we say using our articulators (lips, tongues, teeth, vocal cords, throats, and facial/neck muscles)

What is a corpus callosotomy?

a surgical procedure used to treat seizures by dividing all or part of the corpus callosum

What is the visual perception process?

• pathway serving visual perception originates in the retina

• Retinal ganglion cell axons from the nasal retina cross at the optic chiasma and progress to the LGN of the thalamus

• visual pathways continue from the LGN to the primary visual cortex and towards higher-order visual areas of the occipital, temporal, and parietal lobes

• the left visual field projects to the right side of the brain, and the right visual field projects to the left side of the brain

• visual information is transferred between both hemispheres via the corpus callosum

What are saccades?

rapid eye movements that shift from one point to another

What is the process of when a split-brain indiviual focuses on an object in their left visual field?

• the image is sent to the right visual cortex

• the information cannot cross the corpus callosum due to it being severed

What is the process of when a split-brain individual focuses on an object in their right visual field?

• the image is transferred through the left visual cortex

• then to the Broca’s area

• information cannot go to the right visual cortex because the corpus callosum is severed

Which brain regions in the left hemisphere are associated with language?

• the auditory cortex

• Wernicke’s area

• Angular gyrus (Geschwind’s area)

• Broca’s area

• the motor cortex

What lobe is the auditory cortex in?

the temporal lobe

What does the auditory cortex do (pertaining to language)?

identify pitch and loudness of sounds

Which lobe is Wernicke’s area in?

the temporal lobe

What is the function of Wernicke’s area?

the comprehension of language

Which lobe is the angular gyrus (Geschwind’s area) in?

the parietal lobe

What is the function of the angular gyrus (Geschwind’s area)?

involved with sensorimotor integration, spatial attention, visuomotor, and auditory processing.

Which lobe is Broca’s area in?

the frontal lobe

What is the function of Broca’s area?

the production of language

What is the function of the arcuate fasciculus?

its axons connect Broca’s and Wernicke’s areas

Which lobe is the motor cortex in?

the frontal lobe

What is the function of the motor cortex (pertaining to language)?

motor control of the lips and mouth

What is the most common type of fluent aphasia?

Wernicke’s aphasia

What is Wernicke’s aphasia?

an individual has fluent speech but poor comprehension of language

Which is Broca’s aphasia?

an individual has non-fluent speech but can understand language

What is conduction aphasia caused by?

lesion of the arcuate fasiciulus

What is conduction aphasia?

an individual can express and comprehend language but are unable to repeat words

What is the Wernicke-Geschwind Model of Language for repeating a spoken word?

• receive information from the auditory cortex

• processed in Wernicke’s area for comprehension

• projected onto Broca’s area for speech production

• moves to motor cortex to move lips

What is the Wernicke-Geschwind Model of Language for repeating a written word?

• receive input information from primary visual cortex

• processed in Wernicke’s area for comprehension

• moves to Broca’s area for speech

• moves to the motor cortex to move the lips

What are the two types of streams in the Dual-Stream Model of Language?

ventral and dorsal stream

What is the function of the ventral stream?

processes speech signals for comprehension

What is the function of the dorsal stream?

maps acoustic speech signals to the articulatory networks of the frontal lobe for production

How is the ventral stream organized?

bilaterally

Is the dorsal stream left-hemisphere or right-hemisphere dominant?

left hemisphere

True or False: Some people use the right hemisphere for language production

true

What is important to know about universal language?

• the language network in the brain shows similar properties across 45 languages

• the language areas are lateralized to the left hemisphere, selective for language, and strongly functionally inter-connected

What are the four developmental stages of the early language acquisition?

• phonological development

• semantic development

• syntactic development

• pragmatic development

What is phonological development?

the acquisition of knowledge about how sound distinguishes meaning

What is semantic development?

learning the system for expressing meaning in a language

What is syntactic development?

learning the rules for combining words

What is pragmatic development?

acquiring knowledge of how language is used, including conversational conventions

In regard to language, what can a children at age 1 do?

can say 1 word

In regard to language, what can a two-year-old do?

can say 2 words together

In regard to language, what can a 3+ year old do?

can put words into a sentence

What is important to know about the study done about early language acquisition?

listening to speech activates extensive areas in the temporal lobe, with the activation strongly biased towards the left hemisphere in infants

What is important to know about the study about the social impact on language acquisition?

infants learn more easily from interactions with human beings speaking another language than they do from audiovisual exposure to the same language material

What is important to know about the study on the critical period of language acquisition?

• the fluency of Chinese-American individuals due to exposure to English declines after the age of 7

• different brain areas are active during language-based tasks between children and adults

What is important to know about the study on native and second languages?

second languages acquired in adulthood (‘late’ bilingual subjects) are spatially separated from native languages (‘early’ bilingual subjects) in Broca’s area

What is important to know about the neurobiology of sign langauge?

• the neural systems of signed and spoken language are very similar

• both involve left hemisphere lateralization networks

What is important to know about the study done on language and perception?

• Russian speakers were faster to discriminate two colors when they fell into different linguistic categories in Russian (one light blue and the other darker blue) than when they were from the same linguistic category (both light blue or both dark blue)

• language and perception are two central cognitive systems that constantly interact and rely on each other