Chap 11 Flashcards
What are the 4 main variables of laterality ?
- Laterality is relative
- Cerebral site is as important as cerebral side
- Laterality is effected by genes and the environment
- A range of animals exhibit laterality
What are the first 4 major anatomical differences of the brain ?
- Right hemisphere > left (but less gray matter in the right)
- Asymmetry in the temporal lobes
- Asymmetry in the thalamus correlate with that of the temporal lobes
- Slope of the lateral fissure is less steep on the right
What are the last 4 major anatomical differences of the brain ?
- Frontal operculum is organized differently
- Asymmetry in neurotransmitter distribution
- Right hemisphere extends farther posteriorly
- Asymmetry is effected by gender and handedness
Give two examples of specific brain regions that are asymmetrical
- Wernicke’s area is 1 cm longer on the left
- Heschyl’s gyus is double on the right
What is double dissociation ? Give an example
Specific tests that can demonstrate two related mental processes function independently from one another
- ex. language comprehension and speech
Describe commissurotomy and how it effects visual processes
commissurotomy is the separation of the corpus callous (separation of connection between the hemisphered)
- the left hemisphere is the “speaking hemisphere” therefore only visual input from the right visual field will produce a corresponding verbal response from the patient
What is each visual field primarily responsible for ?
- right visual field: verbal information
- left visual field: faces and visuospatial stimuli
What is the chimeric figures-test ?
A picture of the half of two faces combined, presented quickly
- person picks the face from the left side, shows right hemispheres has a role in facial recognition
Describe the carotid amobarbital injection ?
the injection provides temporary anesthesia to one side of the brain
- showed that when the left hemisphere is anesthetized no speech production
- some % of left handers have speech disturbance if injected on either side of the brain
What is the Kimura dichotic listening model ?
When ipsilateral pathways of hearing are suppressed, the person can only report on auditory information presented on the right that is processed in the left (speaking) hemisphere
What are somatosensory asymmetries in regards to the right vs left hand ?
In right handed participants, the left hand is better at recognizing shapes, the right hand is better at recongizing letters
What causes apraxia
left-hemisphere lesions
What does direct observational research show about motor asymmetry ?
- asymmetry is moderated by native-hand preference
- right side of mouth makes larger movements when talking
What do interference tasks show about motor asymmetry ?
Piano playing example
- humming disrupts the left hand from playing
- speaking disrupts the right hand from playing
What are the 5 specialization models ?
- Kimura
- verbal communication evolved from gestural communication - Leipmann
- left hemisphere specialized for motor control - Efron
- left hemisphere specialized for fine resolution of stimuli - Efron
- LH specialized for temporal resolution and RH for spectral resolution - Semmes
- LH acts more focalized, RH acts more diffusely
