specific functions on specific to one side of the cortex rather than bilateral

brain injuries “split brain” patients imaging studies

left hemisphere◦ analytical abilities◦ quantitative skills◦ language

right hemisphere◦ music◦ spatial abilities◦ artistic abilities◦ emotions◦ facial recognition

most well studied lateralized behavior◦ 95% of right handed have

speech on left◦ 70% of left handed have

speech on left

aphasia – language deficit that cannot be attributed to motor, motivational, sensory or other explanations

characterized by broken halted speech, absence of prosody

non-fluent aphasia

Frontal lobe

agrammatism◦ difficulty in comprehending or properly employing

grammatical devices, such as verb endings and word order.

anomia◦ Difficulty in finding (remembering) appropriate word

articulation◦ difficulty mispronouncing words

Copyright © Allyn & Bacon 2007 9

Can’t just be motor or it wouldn’t be an aphasia

Grammatical issues with connecting words

The lion was killed by the leopard.

lion killed leopard.

Can’t just be motor or it wouldn’t be an aphasia

Grammatical issues with connecting words

Non-fluent aphasia

Comprehension – fairly good; ability to read – fairly good

Copyright © Allyn & Bacon 2007

Part of the Boston Diagnostic Aphasia Test

Copyright © Allyn & Bacon 2007

deficits observed depend on individual as well as where in this region damage occurs…◦ fmri studies…..

◦ INSULAR CORTEX – speech articulation?◦ apraxia?

Copyright © Allyn & Bacon 2007

fluid aphasia, deficits appear to be in comprehension; words are nonsensical

comprehension – poor reading ability - poor

recognition of spoken words comprehension of meaning of words ability to convert thoughts into words

How do we test comprehension in someone that may have Wernicke’s Aphasia?

surgical requirements

injection of sodium amytal or sodium amobarbital – anesthetic

used to determine hemisphere important for speech

split brain surgery

initially – ◦ odd behaviors -

◦ subsequently – only can really tell by experimental manipulations in the lab

◦ Julian Jaynes – “Breakdown of the Bicameral Mind”

Functional brain imaging◦ fMRI or PET used to see which half is active

when doing a language test

Copyright © 2006 by Allyn and Bacon

Copyright © 2006 by Allyn and Bacon

apraxia (of speech)- speech disorder with difficulty speaking correctly; not due to weakness or paralysis of speech muscles (NIDCD); complex motor commands

acquired◦ most typically in adults after brain damage

developmental◦ appears present from birth◦ affects boys more than girls◦ other names – verbal dyspraxia, articulatory

apraxia, childood speech apraxia◦ different than developmental delay of speech

cause or causes unknown may be related to language development may be neurological disorder no specific lesions or imaging studies

helpful family history of communication disorders

or learning disabilities

difficulty putting sounds and syllables together in correct order

longer words more difficult than short inconsistent speech (say word and then

unable) children – comprehension much better than

expression

severity can vary widely

http://www.youtube.com/watch?v=szjfC9K190U&feature=fvsr

http://www.youtube.com/watch?v=XNB0ihI2srQ&feature=related

genetic component family studies twin studies complex in terms of genes complex in terms of etiology complex in terms of traits

◦ can include phonological, auditory, motor, visual deficits which make reading even more difficult