Chapter 14: Cognitive Function Flashcards
describe the visual and auditory connections to the hemispheres
- right hemisphere sees only left half of world
- left hemisphere sees only right half of world
- each ear gets auditory info from both ears but slightly stronger from contralateral ear
- info exchanged through corpus callosum and anterior commissure, hippocampal commissure, and other small commissures
- light from right half of visual field strikes left half of each retina and light fro left visual field strikes the right half of each retina
- left half of each retina connects to left hemisphere sees right visual field
- right half of each retina connects to right hemisphere therefore sees left visual field
Optic Chiasm
-where axon from each eye cross to the opposite side of the brain
why some people have had their corpus callosum cut and how that operation affected their everyday lives and their ability to do conflicting tasks with their two hands
- people with severe epilepsy may have corpus callosum cut
- much less frequent seizure and they stay on one side of body
Split brain people
- maintain intellect motivation and walk without difficulty
- struggle with any hand task not familiar
- can use 2 hands independently of each other
- no trouble planning two actions at same time
- can name object after seeing it in right visual field (left hemisphere) but in left visual field (right hemisphere) usually cannot name or describe it
- 1st weeks post surgery hemispheres act like separate people
functions of the left hemispheres
- focus more on detail
- dominant speech production
functions of right hemisphere
- better at perceiving emotions in gestures and tone of voice
- better at comprehending spatial relationships
- focus more on overall pattern
relationship of handedness and language dominance to the anatomical differences between the hemispheres
-corpus callosum matures greatly between 3 and 5 to facilitate comparison of stimuli between hands
-mature corpus callosum integration of actions with 2 hands
95% of right handed people left hemisphere is strongly dominant for speech
-most left handers are the same but some have right dominance or mix
-use both hemispheres for all but very simple tasks (concept of being right brained or left brained has many flaws)
Planum temporale
-larger left hemisphere for 65% of people
Language abilities of chimps
- seldom use symbols in new original combinations (short of productivity)
- use symbols to request not describe
- ASL, press keys with symbol to request something
- show moderate understanding
Language abilities of Bonobos
- 2 young bonobos developed language comprehension similar to that of a 2-21/2 year old
- understand more than they can produce
- use symbols to name and describe objects even when not requesting them
- request items they do not see
- occasionally use symbols to describe past events
- frequently make original creative requests
Language abilities of Parrots
- can imitate sounds/words
- language needs to be described more precisely
- see study on page 434
problems with the hypothesis that language is a product of overall intelligence
- anyone with a full sized and normal intelligence would have normal speech language (language requires more)
- Williams syndrome- despite mental retardation speak grammatically and fluently
evidence for and against the development of language as a special module
- thought that because children learn language quickly and easily must have language acquisition device (they are biologically prepared)
- speculation language relates to long period of dependency in childhood
- > social interaction among people favoured evolution of language and overall intelligence may be a byproduct
- sensitive period in early life
- very important to learn language in early childhood
Broca’s aphasia causes
- nonfluent aphasia
- lesion on left frontal cortex
- stroke
- damage limited to Broca area produce minor or brief impairment
Broca’s aphasia symptoms
- comprehension deficit with meaning of sentence that depends on preposition, word endings, or unusual word order
- slow and awkward with speaking, writing, and gesturing
Wernicke’s aphasia causes
-damage to Wernike’s area
Wernicke’s aphasia symptoms
- can speak and write but have poor language comprehension and unable to remember names of objects
- person can still speak smoothly
Characteristics of Wernicke’s aphasia
- articulate speech
- anomia
- poor language comprehension
- chart on p440
parallels in the brain between language and music
- trained musicians and music students=better at learning 2nd language
- alter timing, volume, and add emphasis to express emotion
- 0.5-0.7s between beats (English speakers)
- Greek and Balkan have less regular rhythms speakers of these languages write music with irregularly spaced beats
- use language areas of brain when we compose music as we prefer music that resembles rhythms of language we speak
describe the symptoms of dyslexia and some contributing anatomical, physiological, and functional factors
- specific impairment of reading in someone with adequate vision, motivation, and cognitive skills
- linked to 4 genes
- difficulty converting symbols into sounds
- more likely to have bilaterally symmetrical cerebral cortex (planum temporale not bigger)
- do not fit nicely into categories
- most severe cases=damage that restricts field of vision
- most have auditory problems
- difficulty detecting temporal order of sounds
- abnormalities in attention
similarities and differences in the early processing of conscious vs. unconscious stimuli and some factors that can select certain stimuli for consciousness
- if a cooperative person reports awareness of one stimulus and not another than he/she was conscious of the first and not the second
- both types of stimuli excite receptors in the brain
- binocular rivalry makes a stimulus unconscious
masking
-brief stimulus, activates more strongly in conscious condition (without masking)
Unattended stimulus
-meaningful stimulus captures attention faster than meaningless
Consciousness is a threshold phenomenon
-when a stimulus activates enough neurons to a sufficient extent activity reverberates, magnifies and extends over much of the brain
Attention
-aligned with consciousness
Bottom-up
-reaction to stimulus
Top-down
-intentional
describe examples of brain processing of attended vs. ignored stimuli and the implications for the role of attention in this processing
- stroop effect
- directing attention requires increased activity in some neurons and decrease others
describe the symptoms and physical causes of sensory neglect.
- damage to right superior temporal cortex
- damage to superior longitudinal fasciculus
- main problem=loss of attention
- many have deficits in spatial working memory and shifting attention even when location is irrelevant
Spatial Neglect
-tendency to ignore left side of body on left side of objects, also ignore what they hear and feel on left side/hand
