what is the difference between unimodal and heteromodal corticies?
both are association corties
unimodal are modality specific
heteromodal are higher-order functioning
what is one reason for hemispheric specialization?
a reduction in the amount of time it would take to have both hemisphere’s “talk to each other” to accomplish the task
T/F: there is bilateral representation of language centers in many right handers?
FALSE
it is observed in 60-70% of LEFT handers
what is our non-dominant hemisphere primarily responsible for?
- complex visual-spatial skills
- imparting emotional significance to events and language
- music perception
List some clinical features of a non-dominant hemisphere lesion
- visual-spatial analysis/constructional difficulties
- Gestalt difficulties
- tendency toward relatively severe personality and emotional changes
- increased likelihood to have delusions and hallucinations (when compared to the dominant hemisphere)
what is meant by constructional difficulties?
difficulty judging or matching orientation of lines displayed at different angles
(this person would have a hard time drawing more complex shapes but could draw simple ones)
what are gestalt difficuties?
overall spatial arrangement difficulties
(a pt would have difficulty understanding how everything is organized in their visual field, ie. big picture)
List some odd nondominant syndromes
- capgas syndrome
- fregoli syndrome
- reduplicative paramnesia
what is capgas syndrome?
patient insists that their friends and family members have been replaced by identical-looking imposters
what is fregoli syndrome?
patients belive that different people are actually the same person in disguise
what is reduplicative paramnesia?
patient believes that a person, place, or object exists as two identical copies
List some dominant (usually left) hemisphere functions
- Language
- skilled motor function (praxis)
- Arithmetic: sequential and analytical calculating skills
- Musical ability: sequential and analytical skills in trained muscians
- Sense of directions: following a set of written directions in sequence
List some non-dominant (usually right) hemisphere functions
- Prosody (emotion conveyed by tone of voice)
- visual-spatial analysis and spatial attention
- arithmetic: ability to estimate quantity and to correctly line up columns of numbers on the page
- musical ability: in untrained musicians, and for complex musical pieces in trained musicians
- sense of direction: finding one’s way by overall sense of spatial orientation
how do Broca’s and Wernicke’s area communicate?
arcuate fasciculus
List all the regions of the brain associated with language
- inferior lateral primary motor cortex
- Frontal lobes
- supramarginal gyrus and angular gyrus
- visual cortex, visual association cortex
- Non-dominant hemisphere is also involved
- subcotical regions
what is the role of the Frontal Lobe with respect to language processing?
- higher-order motor aspects of speech formation and planning
- syntax
what is the role of the supramarginal and angular gyrus (parietal and tempral lobes) in language?
- lexicon
- writing
what is the role of the visual and visual association cortices in language?
reading
List some syndromes related to aphasia
- Alexia
- Agraphia
- Alexia with agraphia
what is alexia?
an impairment in reading ability
what is agraphia?
impairment in writing ability
alexia without aphasia will have a lesion where?
dominant occipital cortex extending to the posterior corpus callosum (often PCA infarct)
Agraphia without aphasia will often involve a lesion where?
lesion of inferior parietal lobule of language-dominant hemisphere
what is alexia with agraphia?
what regions of the brain does it impact?
aphasia absent or only mild dysnomia and paraphasias
lesions of dominant inferior parietal lobe, region of angular gyrus
