quiz 10 Flashcards
what are anatomical asymmetries of both hemispheres of the brain
- left side larger in posterior, right side larger in anterior
- left planum temporale > right side
what are the functional asymmetries of the hemispheres of the brain
left: language, local processing, recognizing self, spontaneous expressions
right: spatial ability, global processing, melody in music, recognizing others, voluntary expressions
explain split-brain patients
- intact hemispheres, but corpus callosum is damaged
- corpus callosum connects the two and allows the two hemispheres to communicate with each other
explain corpus callosum damage
- cut the corpus callosum to control epilepsy
- hemispheres are still capable of operating independently
-studies are done that restrict visual stimuli to one hemisphere
what are unilateral cortical lesions (also called lateralized lesions)
-one half of brain is damaged
right hemisphere damage: can do spontaneous expression, not voluntary
-opposite is true for left hemisphere damage
explain the global v local processing task
on paper
what is the Wada technique
anesthetize one hemisphere of the brain and assess behavior
-considered invasive; doctors trying to use fMRI instead
how can you look for differences in hemispheres with neurologically intact individuals
-look for perceptual asymmetries when stimuli are presented to two different hemispheres
- divided visual field technique
- dichaptic presentation (left and right hand)
- dichotic presentation (left and right ear)
what is dichotic listening
- right ear (left brain) advantage in dichotic listening to speech sounds
- left ear (right brain) better at hearing melodies
design a study that demonstrates that global processing occurs in the right hemisphere and local processing in the left hemisphere in neurologically intact patients (behavior only study)
- have participants stare at a dot with images flashing on either side (a T made of small Z’s_
- ask them to focus on details, see if they say Z’s faster when the image is on the left than the right (left = local)
- ask them to focus on big picture, see if they say T faster when the image is on the right than the life (right = global)
images will flash quick next to dot, so they don’t have time to focus both eyes on the image
DO NOT PUT BRAIN DAMAGED PATIENTS INTO AN FMRI
why have a lateralized brain?
- we can do more (ex. complex tasks such as language and fine motor control) if we allow the hemispheres to be more specialized (processing is faster for simple tasks)
- primates who show stronger handedness are more effective at the task they do
what does too much lateralization come at the expense off
integrating information, completing multifaceted tasks and protecting yourself from damage
example of measuring inter hemispheric communication study
- 50 ms delay to communicate from one hemisphere to the other
- can measure using an EEG
- people perform better on tasks where hemispheres must communicate to make a decision (do worse when only one hemisphere is utilized)
ex. flashing numbers to see if bottom and one of top #’s = 10
- do worse when 8 and 2 on same side bc only using one hemisphere
- do better when on opposite sides because using both hemispheres
explain inter hemispheric interaction
- when a task is easy, it can be performed faster within hemisphere than across hemispheres
- when a task is hard, it is performed faster when it requires cross hemisphere processing than when it can be completed within a hemisphere
-communicating across hemispheres takes time, but such communication can allow hemispheres to work together more efficiently than alone
explain handedness and hemispheric dominance
- left-handed people may be less lateralized than right handed people
- language can be in the left hemisphere (most often), both hemispheres, or the right hemisphere in left handed people
- handedness observed by age 5 usually
- handedness may be genetic, and/or affected by the womb
