Chapter 14 Lateralization and language and chapter 13 definitions Flashcards
Name three connections between the two hemispheres
- corpus callosum-a set of axons that exhale info between left and right hemispheres
- anterior commissure
- hippocampal commissure
To wich hemisphere(s) does the right visual field project? To which hemisphere(s) does the right half of both retinas project? to which hemisphere(s) does the right eye project?
Right visual field projects to the left side of each eye and hence to the left hemisphere of the brain.
The right half of both eyes project tot he Right hemisphere of the brain. This input info is from the left visual field.
To which hemisphere does the right ear project? What ability requires this distribution of input?
Each ear sends information to both sides of the brain because each of the brain areas that contributes to localizing sods must compare input from both ears. However each ear does pay more attention to the ear on the opposite side
What is the corpus callosum? Why is it sometimes severed in cases of severe epilepsy? What are the effects of such an operation on overall intelligence, motivation and gross motor coordination?
Corpus callosum is the axons that transmit information between each side of the brain.
It is severe in cases of epilepsy to prevent the transfer of information two hemispheres . Epilepsy is a condition characterized by repeated episodes of excessive synchronized neural activity.
What have we learned from split-brain humans concerning specialization of the two hemispheres? Which tasks are best accomplished by left hemisphere?
Each hemisphere has slightly different functions
Split brain people have no trouble planning 2 actions at once
E.g. draw U with left and C with right simultaneously.
L hemisphere understands speech better.
Which functions are best performed by the right hemisphere?
Right hemisphere–good at reading gestures and facial expressions.
Recognizing emotion in others (both pleasant and unpleasant)
-Better at spatial relationships
What is one simple task that can show hemispheric specialization in intact people? How large are the hemispheric differences in intact people?
-simple task- tapping with each hand then tapping while talking.
Talking usually decreases the tapping with R hand more than L hand
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What is planum temporale and what is its significance for language?
A section of the temporal cortex which is larger in the L hemisphere vs right hemisphere
How early is the size difference in the left vs right planum temporal apparent?
infancy before the age of 3 months.
Compare the ability of 3 year olds and of 5 year olds to discriminate fabrics with either one hand or different hands. What ca we infer from this about the development of the corpus callosum?
- 5 year olds did equally well with one hand or two
- 3 year olds made 90% more errors with two hands therefore the corpus callosum matures between ages 3-5 sufficiently to facilitate compression between both hands
In what ways are people who never had a corpus callosum different from split-brain people
without the corpus callosum the brain develops differently.
Perform more slow/less accurately that avg on tasks that require co-operation between 2 hemispheres.
But do better on verbally describing why the felt on each hand and what the see on each visual field.
Which other major axonal connections between the two hemisphere may compensate for the lack of a corpus callosum in people born without one
anterior commisuure
hippocampal commissure
What percentage of right-handed people have left-hemisphere dominance for language? Describe the control of language in left-handed people.
95% for R-handed people
L handed is more variable most have L hemisphere dominance for speech, some have R hemisphere and others have mix.
Is the corpus callosum thicker in right or left handed people? what is the functional correlate of this increased thickness?
Cprous callosum is thicker in lefties.
What are some differences between the abilities of common chimpanzees and humans to use symbols?
Chimpanzees show at least moderate understanding of symbols
Used symbols to request an item–never to describe
Seldom used symbols in new original combinations.
what was unusual about the ability of some bonobos to learn language?
Understand more than they can produce
Use symbols to name and describe objects even when they are not requesting them.
They request items they do not see
Frequently make original, creative requests such as asking one person to chase another.
What ways do bonobos resemble humans more than common chimpanzees in language abilities?
Frequently make original, creative requests such as asking one person to chase another
What evidence is there that the non promote species can learn language?
Parrots are able to mimic / speak
Briefly discuss the proposal that our language may have developed as a by-product of overall intelligence.
Simplest view is that humans evolved big brains, language developed as an accidental byproduct of intelligence–this hypothesis faces series problems
But not all people with normal brain size have normal language skills.
How well do the correlations between intelligence and brain size or between brain intelligence and brain to body ration hold up? How is this a problem for the view that language evolved was a product of large brains and intelligence?
doesn’t correlate–there are people who have normal brain size but severe language deficits.
Describe the pattern of abilities and disabilities in the family with a genetic mutation that produces language deficits. How is this a problem for the view that language evolved as a product of large brains and intelligence?
16 of 30 people over 3 generations show severe language deficits despite normal intelligence in other regard.
Does not support large brains = intelligence and language
Describe Williams syndrome. How does this relate to the evolution of language as a product of general intelligence?
Williams syndrome.–mental retardation but can speak grammatically and fluently
- poor#’s, visual motorskills and spatial perception
- good language (relatively), interpretation of facial expressions, social behaviours and some aspects of music
What is an alternative hypothesis regarding the evolution of language and intelligence?
humans have evolved as a specialized brain mechanism
language acquisition device-i.e. a built in mechanism for acquiring language.
Is there a critical period for language learning? What are some ways of testing this idea
early childhood–starting at age 2-12
Where is Broca’s area located?
left frontal cortex
Describe the effects of damage to Broca’s area. What are closed-class words?
Aphasia-language impairment
If damage only to Broca’s area=brief language impairment
-comprehension deficits if damage is major( (including surrounding areas too)
When they speak=> slow awkward, omit pronouns etc.
Closed class words are prepositions, conjunctions, helping verbs
Contrast the effects of damage to Wernick’s area with those of damage to Broca’s area.
Wernickes- Poor language comprehension and impaired ability to remember the names of objects-also known as fluent aphasia because the person can still speak smoothly whereas Broca’s is language impairment.
Articulate speech-grammatical but often non sensical.
Difficultly finding right words (anomia)
Poor language comprehension.
What broader functions of the temporal and frontal lobes may partially explain specializations of Wernick’s and Broca’s areas
Music
What is dyslexia? How consistent are its symptoms?
A specific impairment inf reading in someone with adequate vision, adequate motivation and overall cognitive skills.
Pertains to difficulty inconverting symbols into sounds.
What are 5 possible biological causes of dyslexia?
- bilaterally symmetric cerebral cotex
- several brain areas in the parietal and temporal cortex have less than average fray matter in children with dyslexia
- possible auditory problems
- others immured control of eye movement
- impairment or abnormalities in their attention
What is one method of improving the ability of dyslexics to read?
Teach them to attend to one word at a time
Use a paper cutout to block out other words.
3 major connections between the hemispheres are:
- corpus callosum
- anterior commissure
- hippocampal commisure
Where does the left visual field project to?
the R half of both retinas which in turn object to the R hemisphere
When drugs and simpler surgery are ineffective what surgery do they perform for epilepsy patients.
corpus callosum is cut.
What is the Wada test?
a test used to test hemispheric dominance for speech; sodium amytal is injected int the carotid artery on one side of the head.
Which hemisphere is more important for expressing and understanding emotional content of speck and facial expression, humour and sarcasm.
Right Hemisphere
Broca’s aphasia
known as non fluent aphasia.
Characterized by difficulty in language production and I’m omission of closed-classed grammatical forms
Wernick’s aphasia
AKA fluent aphasia, is characterized by articulate speech, combined with anomia (difficulty finding the right word) and poor comprehension of nouns and verbs.
temporal lobe impt for what type of memories?
Declarative memories especially for names and irregular verbs
Frontal lobe impt for what type of memories.
procedural memories, including rules for regular verbs
dyslexia
specific impairment of reading, together with adequate vision and other academic skills.
alzheimers disease
condition characterized by memory loss, confusion, depression, restlessness, hallucinations, delusions, sleeplessness, and loss of appetite.
