Speech Production and Aphasia
Speech Production
• Includes a selection problem:
Concept
Select from
possible words
Motor output
Brain Regions for Speech Production
• Wernicke’s Area
• Broca’s Area
• Insula
Wernicke’s and Broca’s are densely
interconnected
• Connected by white-matter tract called the
Arcuate Fasciculus
Catani et al. 2005
Aphasia
• Much of what we know about language
comprehension and production comes from
lesion studies
• Lesions anywhere in the network (including
white matter) can result in complex language
deficits
Aphasia
• Broca’s Aphasia
– Patient “Tan”
– Classically thought of as
a production deficit
– But the sometimes make
exclamations and swear
!?
– Note that Patient Tan’s
lesion extended into the
insula
Aphasia
• Wernicke’s Aphasia
– Classically thought of as a comprehension deficit
– But lesions to Wernicke’s area result in production
deficits:
• Non-sensical “word salad”
Aphasias are infamously complex
• Why might the clinical picture of aphasia be
complicated?