Language and Lateralization Flashcards
What is the division of labor in the brain between hemispheres called?
Lateralization
What happens if we sever the corpus callosum?
We would have two distinct hemispheres that could not communicate with each other
Why might the severing of the corpus callosum be done?
Used to treat epilepsy sometimes, called a corpus callosotomy
How is sensory information processed in the brain (directionally)?
Contralateral
Words seen in the Right hemisphere or left __________ go to the _______________ for comprehension.
1) Visual field
2) Left hemisphere
If we ask a split-brain patient to draw (with their left hand) what they saw in the left visual field, what do you
think would happen?
They can draw it, but they can’t tell you why they drew it. Comprehension would go to the alternate side.
Tachistoscope
Used to briefly flash words to left or right visual fields
If an object (e.g., pear) is
flashed in the left visual
field, can the split brain
subject identify the
correct object with their
left hand?
Yes, because left-hand is controlled by the right hemisphere
If an object (e.g., pear) is
flashed in the left visual
field, can the split brain
subject identify the
correct object with their
right hand?
No, because the right-hand is controlled by the left-hemisphere
Complete lack of the corpus callosum
callosal agenesis
What hemisphere is associated with language in both right and left handers?
Left
What is the right ear advantage?
When competing sounds are presented, the right ear sound will be more clear than the left one because it is being processed in the left-hemisphere which is associated with language.
What else influences the right ear advantage?
Handedness and language domination
Up to ____ of left-handed people show a reduced or reversed right ear advantage
50 percent
Wada Test
A medical test used to assess
hemispheric dominance for language
and memory functions in the brain
Transcranial Magnetic Stimulation (TMS)
Uses an electric current to switch off parts of the brain
What is the planum temporale?
This is the superior surface of the temporal lobe and is larger in the left hemisphere, in most brains, especially babies
Perception of music
Right hemisphere
Perfect pitch
Left hemisphere
Agraphia
Impaired writing abilities
Alexia
Impaired reading abilities (eg. dyslexia)
Micropolygyria
Subtle differences in cortical folding patterns for people with dyslexia
Ectopias
These are small clusters of neurons that have migrated to the wrong location during brain development- more common in the language areas.
Aphasia
Impaired language abilities
In 90-95 percent of cases, aphasia results from damage to the _____________.
Left hemisphere
Brocas area
Frontal lobe, very important for language processing
Anterior regions of Brocas area are important for
Semantic processing
Posterior regions of Brocas area specialize in
Phonological processing (sounds of words)
Non-fluent or Brocas Aphasia
Damage to left-inferior frontal region, trouble generating and producing speech, but have intact speech comprehension
What is Brocas Aphasia caused by?
Strokes or trauma to the brain
What is Borcas Aphasia associated with?
hemiplegia (complete paralysis to one side) or
hemiparesis (weakness with one side)
Wernickes aphasia, fluent aphasia area affected
Damage to the left junction between the upper temporal lobe and parietal lobe. This results in fluent aphasia or Wenickles aphasia.
What is fluent aphasia
Speech can be produced easily, but it does not make sense always
-Paraphrasis: Incorrect word insertions
-Problem of comprehension
Connectionist mode of aphasia
Attributes language deficits to disconnections between regions of the brains language network.
The arcuate fasciculus
a tract believed by
some to connect Wernicke’s and Broca’s
areas, is a key component.
Conduction aphasia
An impairment in the ability to correctly repeat words
Global Aphasia
Damage to left hemisphere including brocas aphasia and wernickles area, little to no comprehension and production of speech.
PET Scans in Diagnosing Aphasia
Show brain areas with reduced activity related to language.
What factors affect aphasia recovery?
Cause and severity of brain damage: The type and extent of the injury, as well as, the areas of the brain affected.
Age and overall health: Younger individuals and those in good health tend to have better recovery prospects
Time since onset: The earlier therapy begins after the injury,
the better the chances of improvement.
Right hemisphere plays a role in emotional tone of voice ________ and in the perception of __________.
1) Prosody
2) Music
Astereognosis
The inability to recognize objects by touching and feeling them.
Temporoparietal junction (TPJ)
Brain region associated with reflexive shifts of attention
- Shifting attention from one target object to the next
- Shifting attention to unexpected or surprising stimuli
Ventral frontal cortex
brain region associated with working memory
- Recognizing the novelty of a
situation by comparing present
stimuli with those of the recent past
- Novel situations = more attentional
resources
Hemispatial Neglect
An individual with right hemisphere
damage (typically in in the TPJ & VFC)
often ignore left side of images
Prosopagnosia
Face blindness- Inability to recognize one’s own face and the face of others
Damage to what area typically results in Prosopagnosia
Fusiform Gyrus
Developmental Prosopagnosia
Where a person has prosopagnosia
without having brain damage
Acquired prosopagnosia
Where a person develops
prosopagnosia after brain
damage, often following
a stroke or head injury
Right Hemisphere Summary
-Important for attention, especially attention to left side of world
- Object identification
- Recognizing meaning from faces
- Recognizing self from non-self
