Brain and Language Where is it?

How do we study language and the brain? Neurolinguistics studies the neurological bases of language  Explores how the processing involved in language takes place across nerves  Pays close attention to chemical and electrical processing in the brain Psycholinguistics studies the psychological underpinnings of language  Focuses on acquisition, storage, comprehension, and production

What is the geography of the brain? Physical structures  Brain divided into two hemispheres  Hemispheres connected by the corpus callosum, a bundle of nerves that serves as the conduit of communication between the two sides of the brain  Brain covered by a ¼ inch thick membrane called the cortex thought to be responsible for higher cognitive functioning

Illustrations of the Brain 3-D Brain Anatomy Princeton Brain Site PET Scans of Verbal Tasks

Speech Areas Broca’s Area  Seems to govern production of language  Adjacent to the motor center that governs the speech organs  Organizes the articulation patterns of speech Wernicke’s Area  Seems to govern comprehension of speech  Located near the auditory cortex Arcuate fasciculus  Connection between the two  Allows the interaction of production and comprehension Angular Gyrus  Connects visual cortex to the auditory cortex  Allows us to read

Models of Language Processing Production of language  Wernicke’s area activated when accessing lexicon Demonstrates WA is involved in associating sound patterns with meaning  Arcuate fasciculus transmits phonetic information from Wernicke’s to Broca’s area Demonstrates that AF is involved in breaking information from WA down into component pieces  Broca’s area interprets information from arcuate fasciculus; transmits articulatory information to motor cortex Demonstrates that BA takes information from AF and controls the mechanics of production  Speech

More Processing Reading a word (silently)  Visual cortex processes visual information from eyes  Angular gyrus associates written word with lexical information Reading processing problems are possibly associated with this area  Wernicke’s area activated during lexical accessing and makes the meaning available Reading aloud (follows steps on previous slide)

And Even More Hearing and repeating  Auditory cortex processes information from the ears Right ear advantage—is this true for you?  Wernicke’s area matches auditory stimulus to lexical information  Arcuate fasciculus transmits phonetic information from Wernicke’s to Broca’s area  Broca’s area interprets information received from AF and transmits articulatory instructions to the motor cortex  Motor cortex directs movement of muscles for articulation

Language Disorders Aphasias are inability to perceive, process, or produce language due to physical damage to the brain Broca’s aphasia results in an inability to produce sequences of sounds in fluent speech; tendency to eliminate any functional vocabulary  Non-fluent aphasia Wernicke’s aphasia results in inability to understand speech and inability to speak meaningfully  Fluent aphasia Acquired dyslexia and Acquired dysgraphia due to angular gyrus damage