Lateralization and Language Flashcards
What hemisphere are language centers in
Left hemisphere
Describe what happens a key is shown to the right visual field and the left visual field in a split brain patient
Left: visual info about the key is sent to right hemisphere, and cannot cross over to the left hemisphere language center leading to an inability to verbalize what they see
Right: visual info about the key is sent to the left hemisphere, leading to an ability to verbalize what they see
What type of fibers are in the corpus callosum
Mostly inhibitory
What occurs across our brain due to the inhibitory nature of the corpus callosum fibers
Leads to one hemisphere competing with the other for the type of processing that occurs
What happens when a split brain patient is shown a different object in each visual field (spoon and pencil) and asked to use both hands to pick up the object seen
Right and left hands see different things to pick up and therefore cannot agree to pick up one thing. This leads to picking up a different object or one hand preventing the other from performing the task
What hemisphere dominates in a visual field task “competition” in split brain patients
Left hemisphere, even if the response isn’t verbal
What is dichotic presentation
When one ear hears one sound while the other hears another, different sound
What ear has an advantage in dichotic presentation and why?
Information presented to the right is the sound that gets repeated as it crosses straight over to the left hemisphere language center
- Opposed to sound in the left ear that crosses over to the right then back over to the left which takes more time
What demographic of people may have a left ear advantage in dichotic presentation
Left handed people, about 50%
What effect does being a musician (well trained in auditory processing) have on the brain
Leads to a highly asymmetrical brain, with larger planum temporale on the left side
What side of the brain has the larger auditory cortex (both primary and secondary)
Left hemisphere
Tachistoscope test
Test where stimuli are very briefly exposed in either the left or right visual field
Planum temporale
A brain area in the superior temporal lobe adjacent to the primary auditory area that is larger in the left hemisphere than the right in most adults
Prosody
Perception of emotions in a person’s tone of voice
What hemisphere is responsible for prosody
Right hemisphere
Wada test
An anesthetic (sodium amytal) is injected into the carotid to anesthetize one hemisphere at a time
Fusiform gyrus
Brain region at the temporo-occipital junction associated with face recognition
When presenting a composite face (celebrity and participants face) to a participant, what occurs when the left hemisphere in anesthetized?
Participants are able to recognize themselves in the composite even with the left hemisphere asleep
When presenting a composite face to a participant, what occurs when the right hemisphere in anesthetized?
Participants are unable to recognize themselves and usually see the celebrity in the composite
Bilateral destruction of the Fusiform gyrus leads to what condition
Prosopagnosia (aka face blindness) where they lose the ability to recognize faces
What happens when a split brain patient is asked to perform a visuospatial task with both hands (duplicating a pattern on blocks)
The split brain patient can duplicate the pattern with their left hand (right hemisphere), but is unable to do so with their right hand (left hemisphere)
Hemisphere superior at visuospatial tasks
Right hemisphere
Split brain patients and asymmetrical tasks
Split brain patients are much better at reconstructing asymmetrical patterns/carrying out conflicting motor programs
- Spatial representations of movements are isolated to each hemisphere
Propose an evolutional theory for the lateralization of language and perception
Right and left hemispheres change from being both allocated for perceptual groupings due to a mutation. The left hemisphere begins to accommodate the development of language. This organization was maintained because the corpus callosum connects the two hemispheres with no extra cost
Which hemisphere has an advantage at interpreting Gestalt images
Both hemispheres can see illusory shapes, but when outlines disturb the Gestalt image only the right hemisphere can still see the illusion
- Left hemisphere no longer perceives the image as a whole
How does the left hemisphere think and organize thoughts
Through semantic processing/categorical memory (a robin is a bird, birds are animals, animals are living things)
How does the right hemisphere think and organize thoughts
Specialized for episodic memory; puts events together and is more relational than categorical
What happens when a split brain patient is asked to write a word seen in their visual field
If presented to the left hemisphere, they are unable to write the word seen
If presented to the right hemisphere, they can write the word
Phoneme
A sound produced for language (f, a, n, u, th)
Morpheme
A word or the smallest part of a word that is meaningful (type, un, able)
Nonfluent speech
Talking with considerable effort, short sentences, and without melody
Broca’s area
Language center in the left anterior frontal hemisphere
Broca’s (nonfluent) aphasia
Leads to nonfluent spontaneous speech (difficulty producing speech), but still have the ability to comprehend speech
Wernicke’s area
Language center in the left hemisphere where the parietal lobe joins temporal lobe
Wernicke’s (fluent) aphasia
Are able to speak well, but cannot comprehend language
Brain of “tan”
A patient that was only able to say the syllable “tan” after a brain injury led Paul Broca to identify damage in what is now called Broca’s area
Global aphasia
The total loss of ability of language; unable to speak, read, write
Damage to what brain region leads to word blindness
Angular gyrus
Damage to what brain region leads to global aphasia
Widespread left hemispheric damage
Connectionist model of aphasia
States that Broca’s and Wernicke’s area are connected by the arcuate fasciculus, and language deficits stem from the lack of connection between these two rea
Pathway of speaking a heard word according to connectionist model
- Auditory transmits info about a word heard to Wernicke’s area
- Wernicke’s area comprehends what the word means and transmits this info via the arcuate fasciculus to Broca’s area
- Broca’s area creates a speech plan and sends it to the motor cortex
Conduction aphasia
Ability to speak and comprehend language, but trouble with repetition of spoken words and sentences due to lesioning of arcuate fasciculus
Pathway of speaking a written word according to connectionist model
- Visual cortex analyzes the seen word and transmits info to angular gyrus
- Angular gyrus recognizes the word
- Wernicke’s area associates the visual form of the word with its spoken form
- Wernicke’s area sends info to Broca’s area via arcuate fasciculus
- Broca’s area creates a speech plan and sends it to the motor cortex
Bilingual patients and language organization
Through stimulation, it was found bilingual patients have very fine tuned subregions that control one language or the other
How can transcranial magnetic stimulation (TMS) affect brain activity
Can be used to create a temporary brain lesion
How does TMS affect behavior when applied to the anterior region of Broca’s area
Affects processing of the meaning of words
How does TMS affect behavior when applied to the posterior region of Broca’s area
Affects the processing of speech sounds
Brain region most active in viewing words
Posterior area in left hemisphere
Brain region most active in passive hearing of words
Temporal lobes
Brain region most active in orally repeating words
Bilateral motor cortices, supplementary motor cortex, portion of cerebellum and insular cortex
Brain region most active in generating associated verb
Language regions in the left hemisphere, especially Broca’s area
Gene implicated in ability for normal acquisition of language
FOXP2
Effect of mutation of FOXP2 gene
Taking a long time to learn how to speak, as well as long lasting difficulties with particular language tasks
The FOXP2 gene thins gray matter in what brain regions?
Frontal cortex, basal ganglia, and cerebellum
Deep dyslexia
An acquired dyslexia where a person reads a word as another word related in meaning (reading cow as horse)
Surface dyslexia
An acquired dyslexia where a person has trouble with words with irregular sounds (plough, tough, dough, cough)
Does surface dyslexia occur in all languages?
Doesn’t occur in languages that are perfectly phonetic such as Italian, but occurs often in English showing some learned aspect of language
Micropolygyria
Small regions of the brain have more folds than usual
Ectopia
Clusters of neurons in unusual locations
Brain differences in people with dyslexia
- Symmetrical planum temporales (should be asymmetrical)
- Anatomical anomalies in the brain are more often seen in the left hemisphere
- Micropolygyria and ectopia in unusual areas
Brain differences in children with dyslexia when processing phonemes in a rhyming task
Decreased activity in left inferior parietotemporal and fusiform regions, independent of IQ
Chronic traumatic encephalopathy (CTE)
Dementia that occurs in athletes that are subjected to repeated blows to the brain
What brain changes are seen in people with CTE
