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
Sensitive period for language development
4-5 years
Broca’s Aphasia
Nonfluent Aphasia- only produces brief or minor language impairment productions
comprehensions deficits when sentence structure is complicated, slow and awkward with all forms of expressions, speaking writing and gesturing, omit pronouns, prepositions, conjunctions and helping verbs, trouble understanding the words they omit
Wernicke’s Aphasia
Patients can speak and write, but language comprehension is poos, impaired ability to remember the names of objects
articulate speech, difficulty finding the right word, anomia, make up names
Dyslexia
specific impairment in reading in someone with adequate vision and adequate skills in other academic areas
more common in boys, linked to at least four genes that produce deficits in hearing or cognition, mild abnormalities in the structure of brain areas, more likely to have bilaterally symmetrical cerebral cortex
Dysphonetic dyslexics
have trouble sounding out words and try to remember each word as a whole
Dyseidetic Dyslexics
sounds out words okay, but fail to recognize word as a whole
Dualism
belief that the mind and brain are different kinds of substance and exist independently
Descartes main problem?
how does the immaterial mind work on the body?
solution- mind and body interact at a single point in space- the pineal gland
Monism
the belief that the universe consists of only one kind of substance
Masking
a brief visual stimulus preceded and followed by longer interfering stimuli, used to prevent consciousness
Backward masking
just the later stimulus is presented
Binocular Rivalry
slow and gradual shifts in perception from one eye to the other
each shift in perception is accompanied by a shift in the pattern of activity over a large portion of the brain
Meaningful stimuli capture our attention
faster than meaningless stimuli, somehow your brain had to know it was meaningful before it became meaningful
phi phenomenon
if you see a dot in one position, alternating with a similar dot nearby, it will seem to you that the dot is moving back and forth
Bottom- up attention
reaction to stimulus
Top-down attention
intentional and controlled
Deliberate top=down direction of attention depends on parts of the
prefrontal cortex and parietal cortex
Spatial Neglect
a tendency for many people with damage to parts of the right hemisphere to ignore the left side of the body or left side of objects
main problem is attention, not impaired sensation
Many patients with neglect also have deficits with
spatial working memory and with shifting attention even when location is irrelevant
