Language and the brain Introduction to Linguistics

Language + brain = neurolinguistics The study of the neural and electrochemical bases of language development and use psycholinguistics The study of the acquisition, storage, comprehension, and production of language

The brain

Physical features of the brain Temporal lobe Perception and recognition of auditory stimuli Frontal lobe Higher thinking and language production Parietal lobe Least involved in language perception and production Occipital lobe Vision Hemisphere Auditory Visual Motor Cortex

Language centers

Language production Broca’s area Language comprehension Wernicke’s area Connection between Broca’s area and Wernicke’s area Arcuate fasciculus Converts visual stimuli into auditory stimuli, or vice versa. The capacity to read and write Angular gyrus

Producing a spoken word Motor cortex Directing the movement of muscles for articulation Broca’s area Interpreting the received info Arcuate fasciculus Phonetic info from W to B Wernicke’s area Accessing the lexicon

Hearing a word Auditory cortex Processing received info by ears Wenicke’s area Interpreting the info and matching it to a lexical entry

Reading a word Visual cortex Processing received info by eyes Angular gyrus Associating written form of word with lexical entry Wenicke’s area Making available the meaning and pronunciation of word

How the brain works The brain is composed of neurons. –Neurons are the basic units of information processing in the nervous system. –There are about 10 billion interconnected neurons.

LATERALIZATION OF BRAIN HEMISPHERES

Contralateral

Split brain experiments The two hemispheres of the brain is connected by corpus callosum. The function of corpus callosum –To commute the info between the two sides of the brain.

What would happen if corpus callosum is cut? Play the split brain experiments game at dicine/split-brain/index.html dicine/split-brain/index.html

Aphasia

A language disorder produced by brain damage Major types –Broca’s aphasia –Wernike’s aphasia

Broca’s aphasia (Expressive aphasia) Symptoms –Unable to express themselves by more than a single word at a time –Content words are ok; function words are not –“Yes... ah... Monday... er... Dad and Peter H... and Dad.... er... hospital... and ah... Wednesday... Wednesday, nine o'clock... and oh... Thursday... ten o'clock, ah doctors... two... an' doctors... and er... teeth... yah’” Damaged area –The front regions of the left hemisphere

Wernike’s aphasia Symptoms –Fluent speech with no informational value –Comprehension is impaired. “I called my mother on the television and did not understand the door. It was too breakfast, but they came from far to near. My mother is not too old for me to be young.” Damaged area –Temporal lobe of the left hemisphere

Broca vs. Wernicke Broca’s aphasia –Prevents a person from producing speech –Person can understand language –Words are not properly formed –Speech is slow and slurred. Wernicke’s aphasia –Loss of the ability to understand language –Person can speak clearly but the words that are put together make no sense.

Conduction aphasia No connection between Broca’s area and Wernike’s area Symptoms –Be able to understand and produce speech, but cannot repeat what they have just heard.

Dyslexia –The impairment of reading ability Symptoms Problems with spelling Reading difficulties Difficulties in recognizing individual sounds in words Difficulties in naming things. Problems organizing in the right order

Brain plasticity The ability of the brain to reorganize the neural pathways based on new experiences. –The environment plays an important role. The implications on learning?

QUESTIONS?