chapters 11-12: cerebral asymmetry, differences in cerebral organization Flashcards
What does laterality mean?
Difference in function between the hemispheres
(Left/Right) hemisphere is specialized for language, controls the (left/right) side of the body.
Left, right
(Left/Right) hemisphere is specialized for nonverbal information, controls the (left/right) side of the body.
Right, left
Lateralization is (relative/absolute).
Relative (both hemispheres involved in almost all behaviours).
What is the functional name of Wernicke’s Area and how/where is it lateralized?
Wernicke’s Area (planum temporale): secondary auditory cortex; left-lateralized for most.
What is the functional name of Heschel’s Gyri and how/where are they lateralized?
Heschel’s Gyri: primary auditory cortex; right-lateralized in most. Also two gyri in right vs one gyrus in left.
Motor and sensation functions are mostly (symmetrical/asymmetrical), language function is (symmetrical/asymmetrical).
symmetrical, asymmetrical
How did early epilepsy treatment lead to mapping the cortex (and discovering lateralization)?
Treatment was removing parts of brain, care had to be taken to remove correct areas and not affect other function. Lateralization discovered via mapping.
Weak stimulation of left frontal or temporal lobes (facilitated/inhibited) speech production. Strong opposite.
facilitated
Describe the experimental technique of double dissociation and its purpose.
Double dissociation: two functions, two patients with lesions of associated brain regions. If functions impaired in each as expected, double dissociation confirmed.
Purpose: To show that particular function is associated with particular brain region. Also shows separate organization between two functions of interest.
In split-brain patients, information presented to (left/right) visual field cannot be verbalized about directly.
left
In split-brain patients, information processed by the (left/right) hemisphere is implicitly processed, other hemisphere makes up a reason for behaviour.
right
In split-brain patients, the (left/right) hemisphere acts as the interpreter due language lateralization.
left
What is the process and purpose Wada Test?
Sodium amobarbital (paralytic) is administered (initially via cartoid, later femoral catheter) to one hemisphere for the purposes of functional testing.
__% of right-handers are left-hemisphere language dominant, __% of left-handers.
98, 70
__% of non-right-handers show lack of language lateralization (bilateral speech).
15
What is tachistoscopic presentation and how is it used to determine lateralization.
Tachistoscopic presentation: images presented to individual visual field for less than 50 microseconds using tachistoscope. Accuracy of information compared between hemispheres to determine lateralization.
Faces better processed by (left/right) hemisphere, visuospatial information: (left/right), language: (left/right).
right, right, left
How is the auditory system differentiated compared to left/right visual fields?
Auditory system is less differentiated.
When provided with dichotic inputs, which ear’s input is prioritized?
The contralateral input.
Somatosensory and motor pathways are almost entirely (ipsi/contra)lateral.
contralateral
(left/right)-handers better at understanding braille due language processing being [other]-lateralized.
left-handers
Mouth movements begin on (left/right) side of face, emotions displayed more strongly on (left/right) side.
right, left
How do specialization vs interaction theories differ?
Specialization: different hemispheres have unique functions
Interaction: though one hemisphere may be better at a task, both cooperate
What is one’s cognitive set? How is it relevant to lateralization?
Cognitive set: biases in how individual’s approach problems. Affects results of lateralization tests due individual preference over cerebral organization.
In primates, rapid uni-manual movements favour which hemisphere? whole-body movements?
Right specialized for rapid uni-manual movements, left for whole-body movements.
When is handedness first apparent? what percentage are right handed?
10 weeks post-conception, 90% in writing, 70-90% for other functions.
Do righties and lefties showcase the same degree of hand dominance lateralization?
No. Righties more lateralized.
__% of lefties have leftie language, __% have right language organization (weird), __% bilateral.
70, 15, 15
