Chapter 14- Cognitive Functions Flashcards
The left hemisphere of the cerebral cortex is
connected to skin receptors and muscles mainly on the right side of the body
Left hemisphere only sees…
right half side of the world
Auditory information, each hemisphere gets information
from both ears but slightly stronger information from contralateral ear than from ipsilateral ear
Left side is specialized for
language
Visual field
what is visible at any moment
light from right half of visual field
shines onto left half of both retinas
left half of each retina connects to
left hemisphere, sees right visual field
right half of each retina connects to
right hemisphere, sees left visual field
damage to the corpus callosum
prevents the two hemispheres from exchanging information
split-brain people
people who have undergone surgery to corpus callosum
maintain their intellect and motivations, walk normally and use two hands together on familiar tasks
struggle with less familiar tasks, respond differently to stimuli presented to only one side of the body, can use their hands independently in ways others can’t
Sperry’s studies…
two halves of the brain could communicate with each other, use left hand to point to what right hemisphere had seen, use right hand to point to what left hemisphere had seen
left hemisphere is dominant for speech production in more than
90% of right handed people and 80% of left-handed people
Split-brain patients cannot name objects
in left visual field
The right hemisphere
is better at perceiving emotions in people’s gestures and tone of voice
better at comprehending spatial relationships, focuses on overall patterns
Damage to left hemisphere
prevents it from interfering with right, free to make reliable judgment
People with damage to the right hemisphere
speak in a monotone voice, do not understand people’s emotional expressions, usually fail to understand humor or sarcasm
Do hemispheres differ anatomically?
yes
Planum Temporate
temporal lobe- larger in left hemisphere for 65% of people
difference in size is slightly greater for strongly right-handed people, bigger ratio of left to right planum temporate performed better on language tests
children with equal hemispheres were better on nonverbal takss
Corpus Callosum matures
gradually over first 5-10 years of life, thickens as myelin around certain axons from childhood through adolescence
because connections can take years to develop their mature adult pattern, young children can exhibit certain behaviors similar to those of split-brain adults
Those born without corpus callosum
enables left hemisphere to feel both left and right hands,
brains other commissures become larger than usual
Most left- handers have
left hemisphere dominance for speech
Language as a by-product of intelligence
but not all people with full sized brains have normal language, genetic conditions can impair language without impairing other aspects of intelligence
Williams syndrome
caused by deletion of several genes from chromosome 7, people can speak grammatically and fluently but are far from perfect in language, are poor at tasks related to numbers, visuospatial skills and spatial perception
Language as specialization
LAD, novel sentences and naming explosion