Chapter 14: Cognitive Functions
Lateralization of Function <ul><li>Lateralization  of function refers to the idea that each hemisphere of the brain is spe...
Lateralization of Function <ul><li>The left and right hemisphere exchange information primarily through a set of axons cal...
Fig. 14-2, p. 418
Lateralization of Function <ul><li>The two hemispheres are not mirror images of each other. </li></ul><ul><li>Division of ...
Lateralization of Function <ul><li>Each hemisphere of the brain gets input from the opposite half of the visual world. </l...
Lateralization of Function <ul><li>The left half of each retina connects to the left hemisphere. </li></ul><ul><li>The rig...
Fig. 14-3a, p. 419
Lateralization of Function <ul><li>Damage to the corpus callosum interferes  with the exchange of  information between hem...
Lateralization of Function <ul><li>People who have undergone surgery to the corpus callosum are referred to as  split-brai...
Fig. 14-4, p. 420
Lateralization of Function <ul><li>Sperry (1974) revealed subtle behavioral differences for spilt brain people. </li></ul>...
Fig. 14-5, p. 422
Lateralization of Function <ul><li>Immediately after surgery, each hemisphere can only quickly and accurately respond to i...
Fig. 14-6, p. 423
Lateralization of Function <ul><li>Right hemisphere is better at perceiving emotions. </li></ul><ul><li>Damage to parts of...
Lateralization of Function <ul><li>The right hemisphere is also better at comprehending spatial relationships. </li></ul><...
Lateralization of Function <ul><li>Some anatomical differences exist between the hemispheres of the brain. </li></ul><ul><...
Fig. 14-9, p. 425
Lateralization of Function <ul><li>Damage to left hemisphere often results in language deficiencies. </li></ul><ul><li>Lef...
Lateralization of Function <ul><li>Being born with a condition where the corpus callosum does not completely develop resul...
Lateralization of Function <ul><li>The left hemisphere is dominant for speech in 95% of right-handed people. </li></ul><ul...
Lateralization of Function <ul><li>Recovery of language after damage to the brain varies. </li></ul><ul><li>Age affects ex...
Lateralization of Function <ul><li>Rasmussen’s encephalopathy  is a rare condition in which the immune system initially at...
Lateralization of Function <ul><li>Language recovery after brain damage is also influenced by how language was initially l...
Evolution and Physiology of Language <ul><li>Human language is a complex form of communication. </li></ul><ul><li>Compared...
Evolution and Physiology of Language <ul><li>Human language is most likely a modification of a behavior also found in othe...
Evolution and Physiology of Language <ul><li>Bonobos or pygmy chimpanzees show an increased comprehension of human languag...
Lateralization of Function <ul><li>Non-primates also display some aspects of spoken language. </li></ul><ul><li>Elephants ...
Evolution and Physiology of Language <ul><li>Studies of nonhuman language abilities: </li></ul><ul><li>Give insights to ho...
Evolution and Physiology of Language <ul><li>Two categories of theories attempt to explain the human ability to learn lang...
Evolution and Physiology of Language <ul><li>Problems associated with the “language as a by-product of increased intellige...
Fig. 14-14, p. 433
Evolution and Physiology of Language <ul><li>Evidence suggesting language evolved as an extra brain module specialization ...
Evolution and Physiology of Language <ul><li>Most researchers agree that humans have a specially evolved “something” that ...
Evolution and Physiology of Language <ul><li>Research suggests a critical period exists for the learning of language. </li...
Evolution and Physiology of Language <ul><li>Rare cases of children not exposed to language indicates limited ability to l...
Evolution and Physiology of Language <ul><li>Most knowledge of brain mechanisms of language come from the study of people ...
Evolution and Physiology of Language <ul><li>Broca’s aphasia/nonfluent aphasia  refers to serious impairment in language p...
Evolution and Physiology of Language <ul><li>Broca’s aphasia is usually accompanied by comprehension deficits when:  </li>...
Fig. 14-15, p. 435
Fig. 14-16, p. 436
Evolution and Physiology of Language <ul><li>Wernicke’s area  is an area of the brain located near the auditory part of th...
Evolution and Physiology of Language <ul><li>Typical characteristics of Wernicke’s aphasia include: </li></ul><ul><ul><li>...
Table 14-1, p. 438
Evolution and Physiology of Language <ul><li>Dyslexia  is a specific impairment of reading in a person with adequate visio...
Evolution and Physiology of Language <ul><li>In some cases, dyslexia is associated with mild abnormality in the structures...
Evolution and Physiology of Language <ul><li>Different kinds of dyslexics have different reading problems. </li></ul><ul><...
Evolution and Physiology of Language <ul><li>Most severe cases of “dyseidetic dyslexia” result from brain damage that rest...
Evolution and Physiology of Language <ul><li>One hypothesis to explain dyslexia emphasizes a hearing impairment rather tha...
Evolution and Physiology of Language <ul><li>Another hypothesis to explain dyslexia is connecting vision to sound. </li></...
Evolution and Physiology of Language <ul><li>A final hypothesis relates dyslexia to differences in attention. </li></ul><u...
Fig. 14-17, p. 440
Attention <ul><li>Attention is a multi-dimensional process and related to consciousness. </li></ul><ul><li>Attention relat...
Attention <ul><li>Enhancement of activity can be due to intensity of the stimulus, similarity to past important stimuli, o...
Attention <ul><li>“Inattention” or “neglect” is the opposite of attention. </li></ul><ul><li>Spatial neglect  is a tendenc...
Attention <ul><li>Exact location of the damage to the right hemisphere can affect the details of what the person neglects....
Fig. 14-19, p. 444
Attention <ul><li>Problems of neglect are associated with attention and not sensation. </li></ul><ul><li>Someone with negl...
Attention <ul><li>Several procedures can increase attention to the neglected side: </li></ul><ul><ul><li>telling the perso...
Fig. 14-20, p. 444
Attention <ul><li>Many patients with spatial neglect also have deficits with spatial working memory and with shifting atte...
Attention <ul><li>Attention-Deficit Hyperactivity Disorder (ADHD)  is characterized by the following: </li></ul><ul><ul><l...
Attention <ul><li>ADHD affects social behavior and school performance. </li></ul><ul><li>Some have occupational problems a...
Attention <ul><li>Three example of tasks which people with ADHD differ: </li></ul><ul><ul><li>“The choice delay task” - mo...
Attention <ul><li>Twin studies suggest fairly high heritability (Thapar et al., 2003). </li></ul><ul><ul><li>Several genes...
Attention <ul><li>Structural brain differences include a smaller than average prefrontal cortex and cerebellum. </li></ul>...
Attention <ul><li>The most common treatment for ADHD is stimulant drugs or amphetamines. </li></ul><ul><ul><li>Example: me...
Attention <ul><li>Amphetamines and methylphenidate increase the availability of dopamine to the postsynaptic receptors. </...
Attention <ul><li>Behavioral techniques are available as supplements or substitutes for stimulant drugs: </li></ul><ul><ul...
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  • Chapter14 Power Point Lecture

    1. 1. Chapter 14: Cognitive Functions
    2. 2. Lateralization of Function <ul><li>Lateralization of function refers to the idea that each hemisphere of the brain is specialized for different functions. </li></ul><ul><li>Each hemispheres controls the contralateral (opposite) side of the body. </li></ul><ul><ul><li>Example: skin receptors and muscles mainly on the right side of the body. </li></ul></ul><ul><ul><li>Each hemisphere sees the opposite side of the world. </li></ul></ul>
    3. 3. Lateralization of Function <ul><li>The left and right hemisphere exchange information primarily through a set of axons called the corpus callosum. </li></ul><ul><li>Other areas that exchange information include: </li></ul><ul><ul><li>The anterior commissure. </li></ul></ul><ul><ul><li>The hippocampal commissure. </li></ul></ul><ul><ul><li>A few other small commissures. </li></ul></ul><ul><li>Information crosses to the other hemisphere with only a brief delay. </li></ul>
    4. 4. Fig. 14-2, p. 418
    5. 5. Lateralization of Function <ul><li>The two hemispheres are not mirror images of each other. </li></ul><ul><li>Division of labor between the two hemispheres is known as lateralization . </li></ul><ul><ul><li>In most humans the left side is specialized for language. </li></ul></ul><ul><li>The corpus callosum allows each hemisphere of the brain access to information from both sides. </li></ul>
    6. 6. Lateralization of Function <ul><li>Each hemisphere of the brain gets input from the opposite half of the visual world. </li></ul><ul><li>The visual field is what is visible at any moment. </li></ul><ul><li>Light from the right half of the visual field shines into the left half of both retinas. </li></ul><ul><li>Light from the left visual field shines onto the right half of both retinas. </li></ul>
    7. 7. Lateralization of Function <ul><li>The left half of each retina connects to the left hemisphere. </li></ul><ul><li>The right half of each retina connects to the right hemisphere. </li></ul><ul><li>Half of the axons from each eye cross to the opposite side of the brain at the optic chiasm . </li></ul><ul><li>The auditory system is arranged differently in that each ear sends the information to both sides of the brain. </li></ul>
    8. 8. Fig. 14-3a, p. 419
    9. 9. Lateralization of Function <ul><li>Damage to the corpus callosum interferes with the exchange of information between hemispheres. </li></ul><ul><li>Epilepsy is a condition characterized by repeated episodes of excessive synchronized neural activity. </li></ul><ul><ul><li>Mainly due to decreased release of the inhibitory neurotransmitter GABA. </li></ul></ul><ul><li>Physicians once cut the corpus callosum to prevent the seizure from spreading to the opposite side of the body. </li></ul>
    10. 10. Lateralization of Function <ul><li>People who have undergone surgery to the corpus callosum are referred to as split-brain people . </li></ul><ul><li>Spit brain people maintain normal intellect and motivation but they tend to: </li></ul><ul><ul><li>Use hands independently in a way others cannot. </li></ul></ul><ul><ul><li>Respond differently to stimuli presented to only one side of the body. </li></ul></ul>
    11. 11. Fig. 14-4, p. 420
    12. 12. Lateralization of Function <ul><li>Sperry (1974) revealed subtle behavioral differences for spilt brain people. </li></ul><ul><li>Because the left side of the brain is dominant for language in most people, most split brain people: </li></ul><ul><ul><li>Have difficulty naming objects briefly viewed in the left visual field. </li></ul></ul><ul><li>A small amount of information can still be transferred via several smaller commissures. </li></ul>
    13. 13. Fig. 14-5, p. 422
    14. 14. Lateralization of Function <ul><li>Immediately after surgery, each hemisphere can only quickly and accurately respond to information that reaches it directly. </li></ul><ul><ul><li>Smaller commissures allow a slower response. </li></ul></ul><ul><li>The brain later learns use the smaller connections: </li></ul><ul><li>Difficulty integrating information between both remains. </li></ul>
    15. 15. Fig. 14-6, p. 423
    16. 16. Lateralization of Function <ul><li>Right hemisphere is better at perceiving emotions. </li></ul><ul><li>Damage to parts of the right hemisphere causes difficulty perceiving other’s emotions, failure to understand humor and sarcasm, and a monotone voice. </li></ul><ul><li>Left hemisphere damage increases ability to accurately judge emotion. </li></ul><ul><ul><li>Associated with decreased interference from the left hemispheres. </li></ul></ul>
    17. 17. Lateralization of Function <ul><li>The right hemisphere is also better at comprehending spatial relationships. </li></ul><ul><li>In general, the left hemisphere seems to focus more on visual details, and the right hemisphere focuses more on visual patterns. </li></ul>
    18. 18. Lateralization of Function <ul><li>Some anatomical differences exist between the hemispheres of the brain. </li></ul><ul><li>The planum temporale is an area of the temporal cortex that is larger in the left hemisphere in 65% of people. </li></ul><ul><ul><li>Difference are slightly greater for people who are strongly right handed. </li></ul></ul><ul><li>MRI studies indicate that the a big difference in the ratio of left to right planum temporale is related to increased language performance. </li></ul>
    19. 19. Fig. 14-9, p. 425
    20. 20. Lateralization of Function <ul><li>Damage to left hemisphere often results in language deficiencies. </li></ul><ul><li>Left side seems to be specialized for language from the very beginning in most people. </li></ul><ul><li>The corpus callosum matures gradually through the first 5 to 10 years. </li></ul><ul><ul><li>Thus, young children have difficulty comparing information from the left and right hand. </li></ul></ul>
    21. 21. Lateralization of Function <ul><li>Being born with a condition where the corpus callosum does not completely develop results in extra development of the following: </li></ul><ul><ul><li>Anterior commissure - connects the anterior parts of the cerebral cortex. </li></ul></ul><ul><ul><li>Hippocampal commissure - connects the left and right hippocampus. </li></ul></ul><ul><li>Allows performance on some tasks that differs from split-brain people. </li></ul>
    22. 22. Lateralization of Function <ul><li>The left hemisphere is dominant for speech in 95% of right-handed people. </li></ul><ul><li>Most left-handers have left-hemisphere or mixed-dominance for speech. </li></ul><ul><ul><li>Few people have strong right hemisphere dominance. </li></ul></ul>
    23. 23. Lateralization of Function <ul><li>Recovery of language after damage to the brain varies. </li></ul><ul><li>Age affects extent of recovery. </li></ul><ul><ul><li>Brain is more plastic at an early age. </li></ul></ul><ul><li>Right hemisphere reorganizes to serve some of the left-hemisphere function. </li></ul>
    24. 24. Lateralization of Function <ul><li>Rasmussen’s encephalopathy is a rare condition in which the immune system initially attacks the glia and then the neurons of one hemispheres of the brain. </li></ul><ul><ul><li>Usually begins in childhood or adolescence. </li></ul></ul><ul><li>Surgeons eventually remove or disconnect the side of the damaged brain. </li></ul><ul><li>Language recovers slowly but substantially. </li></ul><ul><ul><li>Slow deterioration allows the other side of the brain to compensate and reorganize. </li></ul></ul>
    25. 25. Lateralization of Function <ul><li>Language recovery after brain damage is also influenced by how language was initially lateralized for the given person. </li></ul><ul><li>Individuals with partial representation of language in both hemispheres recover better than those with language dominance in one hemisphere. </li></ul>
    26. 26. Evolution and Physiology of Language <ul><li>Human language is a complex form of communication. </li></ul><ul><li>Compared to other species, human language has high productivity. </li></ul><ul><ul><li>Productivity - the ability to produce new signals to represent new ideas. </li></ul></ul>
    27. 27. Evolution and Physiology of Language <ul><li>Human language is most likely a modification of a behavior also found in other species. </li></ul><ul><li>Chimpanzees use language but it differs from humans: </li></ul><ul><ul><li>Seldom use symbols in new original combinations. </li></ul></ul><ul><ul><li>Use of symbols lacks productivity. </li></ul></ul><ul><ul><li>Use of symbols is primarily used to request and not describe. </li></ul></ul><ul><ul><li>Production of requests is better than understanding other’s requests. </li></ul></ul>
    28. 28. Evolution and Physiology of Language <ul><li>Bonobos or pygmy chimpanzees show an increased comprehension of human language: </li></ul><ul><ul><li>Understand more than they can produce. </li></ul></ul><ul><ul><li>Use symbols and names to describe objects. </li></ul></ul><ul><ul><li>Request items not seen. </li></ul></ul><ul><ul><li>Use symbols to describe past events. </li></ul></ul><ul><ul><li>Make original, creative requests. </li></ul></ul>
    29. 29. Lateralization of Function <ul><li>Non-primates also display some aspects of spoken language. </li></ul><ul><li>Elephants imitate sounds they hear, including the vocalizations of other elephants. </li></ul><ul><li>Dolphins respond to gestures and sounds. </li></ul><ul><li>The African gray parrot show a great ability for imitating sounds and also using sounds meaningfully. </li></ul><ul><ul><li>Example: Alex the gray parrot. </li></ul></ul>
    30. 30. Evolution and Physiology of Language <ul><li>Studies of nonhuman language abilities: </li></ul><ul><li>Give insights to how best to teach language to those who do not learn it easily. </li></ul><ul><ul><li>Examples: Brain damaged people or children with autism. </li></ul></ul><ul><li>Illustrate the ambiguity of our concept of language. </li></ul><ul><ul><li>Allows for more precise definition. </li></ul></ul>
    31. 31. Evolution and Physiology of Language <ul><li>Two categories of theories attempt to explain the human ability to learn language more easily than other species. </li></ul><ul><ul><li>“Language evolved as a by-product of overall brain development.” </li></ul></ul><ul><ul><li>“Language evolved as an extra part of the brain.” </li></ul></ul>
    32. 32. Evolution and Physiology of Language <ul><li>Problems associated with the “language as a by-product of increased intelligence” theory: </li></ul><ul><ul><li>People with a full-size brain and normal overall intelligence can show severe language deficits. </li></ul></ul><ul><ul><li>People with impaired intelligence can have normal language skills. </li></ul></ul><ul><ul><ul><li>Williams syndrome characterized by metal retardation but skillful use of language. </li></ul></ul></ul>
    33. 33. Fig. 14-14, p. 433
    34. 34. Evolution and Physiology of Language <ul><li>Evidence suggesting language evolved as an extra brain module specialization includes: </li></ul><ul><ul><li>Language acquisition device is a built in mechanism for acquiring language. </li></ul></ul><ul><ul><ul><li>Evidence comes from the ease at which most children develop language. </li></ul></ul></ul><ul><ul><li>Chomsky (1980) further suggests the poverty of stimulus argument : children do not hear many examples of some of the grammatical structures they acquire. </li></ul></ul>
    35. 35. Evolution and Physiology of Language <ul><li>Most researchers agree that humans have a specially evolved “something” that enables them to learn language easily. </li></ul><ul><ul><li>Certain brain areas are indeed necessary for language. </li></ul></ul><ul><ul><li>But same areas are also necessary for other tasks (memory and music perception). </li></ul></ul><ul><li>Exactly how humans evolved language is unknown but is perhaps due to the pressure for social interaction. </li></ul>
    36. 36. Evolution and Physiology of Language <ul><li>Research suggests a critical period exists for the learning of language. </li></ul><ul><li>Learning of a second language differs as a function of age: </li></ul><ul><ul><li>Children are better at learning pronunciation and unfamiliar aspects of grammar. </li></ul></ul><ul><li>No sharp cutoff exist for second language learning. </li></ul><ul><ul><li>Adults learn a second-language vocabulary better. </li></ul></ul>
    37. 37. Evolution and Physiology of Language <ul><li>Rare cases of children not exposed to language indicates limited ability to learn language later. </li></ul><ul><li>Deaf children unable to learn spoken language and not given the opportunity to learn sign language while young reveals: </li></ul><ul><ul><li>Little development of skill at any language later. </li></ul></ul><ul><ul><li>Early exposure to some language increases ability to learn another language later. </li></ul></ul>
    38. 38. Evolution and Physiology of Language <ul><li>Most knowledge of brain mechanisms of language come from the study of people with brain damage: </li></ul><ul><ul><li>Broca’s area is a part of the frontal lobe of the left cerebral cortex near the motor cortex. </li></ul></ul><ul><ul><ul><li>Damage results in some language disability. </li></ul></ul></ul><ul><ul><li>Aphasia refers to a condition in which there is severe language impairment. </li></ul></ul>
    39. 39. Evolution and Physiology of Language <ul><li>Broca’s aphasia/nonfluent aphasia refers to serious impairment in language production, usually due to brain damage. </li></ul><ul><li>Omission of most pronouns, prepositions, conjunctions, auxiliary verbs, tense and number endings during speech production. </li></ul><ul><li>People with Broca's aphasia have trouble understanding the same kinds of words they omit (prepositions and conjunctions). </li></ul>
    40. 40. Evolution and Physiology of Language <ul><li>Broca’s aphasia is usually accompanied by comprehension deficits when: </li></ul><ul><ul><li>The sentence meaning depends on prepositions, word endings or unusual word order. </li></ul></ul><ul><ul><li>Sentence structure is complicated. </li></ul></ul><ul><li>Broca’s area thus seems to be critical for the understanding of some, but not all, aspects of grammar. </li></ul>
    41. 41. Fig. 14-15, p. 435
    42. 42. Fig. 14-16, p. 436
    43. 43. Evolution and Physiology of Language <ul><li>Wernicke’s area is an area of the brain located near the auditory part of the cerebral cortex. </li></ul><ul><li>Wernicke’s aphasia is characterized by the impaired ability to remember the names of objects and also impaired language comprehension. </li></ul><ul><ul><li>Sometimes called “fluent aphasia” because the person can still speak smoothly. </li></ul></ul><ul><li>Recognition of items is often not impaired; ability to find word is impaired. </li></ul>
    44. 44. Evolution and Physiology of Language <ul><li>Typical characteristics of Wernicke’s aphasia include: </li></ul><ul><ul><li>Articulate speech / fluent speech except with pauses to find the right word. </li></ul></ul><ul><ul><li>Difficulty finding the right word - anomia refers to the difficulty recalling the name of objects. </li></ul></ul><ul><ul><li>Poor language comprehension - difficulty understanding spoken and written speech (especially nouns and verbs). </li></ul></ul>
    45. 45. Table 14-1, p. 438
    46. 46. Evolution and Physiology of Language <ul><li>Dyslexia is a specific impairment of reading in a person with adequate vision and adequate skills in other academic areas. </li></ul><ul><ul><li>More common in boys. </li></ul></ul><ul><ul><li>Research suggests a genetic influence. </li></ul></ul>
    47. 47. Evolution and Physiology of Language <ul><li>In some cases, dyslexia is associated with mild abnormality in the structures of various brain areas. </li></ul><ul><ul><li>More likely to have a bilateral symmetrical cerebral cortex. </li></ul></ul><ul><ul><li>Language–related areas in the right hemisphere are larger in some. </li></ul></ul><ul><ul><li>Weak connections exist among other areas. </li></ul></ul>
    48. 48. Evolution and Physiology of Language <ul><li>Different kinds of dyslexics have different reading problems. </li></ul><ul><li>“Dysphonic dyslexics” have trouble sounding out words. </li></ul><ul><ul><li>Attempt to remember them as a whole. </li></ul></ul><ul><li>“Dyseidetic dyslexics” fail to recognize a word as a whole. </li></ul><ul><ul><li>Read slowly and have particular trouble with irregularly spelled words. </li></ul></ul>
    49. 49. Evolution and Physiology of Language <ul><li>Most severe cases of “dyseidetic dyslexia” result from brain damage that restricts the field of vision. </li></ul><ul><li>Characterized by the following: </li></ul><ul><ul><li>only seeing one letter a time. </li></ul></ul><ul><ul><li>short eye movements. </li></ul></ul><ul><ul><li>very slow reading. </li></ul></ul><ul><ul><li>difficulty with long words. </li></ul></ul>
    50. 50. Evolution and Physiology of Language <ul><li>One hypothesis to explain dyslexia emphasizes a hearing impairment rather than visual impairment. </li></ul><ul><ul><li>Less than normal response to speech sounds in the brain. </li></ul></ul><ul><ul><li>Lack of ability to pay close attention to sounds. </li></ul></ul>
    51. 51. Evolution and Physiology of Language <ul><li>Another hypothesis to explain dyslexia is connecting vision to sound. </li></ul><ul><li>Brain scans indicate that reading strongly activates areas of the left temporal and parietal cortex for most people. </li></ul><ul><ul><li>Areas are associated with connecting visual and auditory information. </li></ul></ul><ul><li>Only weakly activated for people with dyslexia. </li></ul>
    52. 52. Evolution and Physiology of Language <ul><li>A final hypothesis relates dyslexia to differences in attention. </li></ul><ul><li>Reading requires the shifting of attention. </li></ul><ul><li>People with dyslexia do not shift their attention in the same way. </li></ul><ul><li>Effective treatment may be for dyslexics to focus on one word at a time. </li></ul>
    53. 53. Fig. 14-17, p. 440
    54. 54. Attention <ul><li>Attention is a multi-dimensional process and related to consciousness. </li></ul><ul><li>Attention relates to increased brain activity in the areas responsive to a stimulus. </li></ul><ul><li>Stimuli destined to become conscious or unconscious produce about the same brain activity in the first 200-250 milliseconds. </li></ul><ul><li>In the next few milliseconds, the brain enhances activity for stimuli that become conscious. </li></ul>
    55. 55. Attention <ul><li>Enhancement of activity can be due to intensity of the stimulus, similarity to past important stimuli, or other features of the stimulus itself. </li></ul><ul><li>Enhancement of activity can also be due to shifting of attention. </li></ul><ul><li>Research suggests that attention pertains more to the enhancing of relevant activity than inhibiting irrelevant activity. </li></ul>
    56. 56. Attention <ul><li>“Inattention” or “neglect” is the opposite of attention. </li></ul><ul><li>Spatial neglect is a tendency to ignore the left side of the body and its surroundings or the left side of objects. </li></ul><ul><ul><li>Often associated with damage to the right hemisphere of the brain. </li></ul></ul>
    57. 57. Attention <ul><li>Exact location of the damage to the right hemisphere can affect the details of what the person neglects. </li></ul><ul><ul><li>Damage to the inferior part of the right parietal cortex leads to the neglect of everything to the left of their own body. </li></ul></ul><ul><ul><li>Damage to the superior temporal cortex neglect the left side of objects, regardless of location. </li></ul></ul>
    58. 58. Fig. 14-19, p. 444
    59. 59. Attention <ul><li>Problems of neglect are associated with attention and not sensation. </li></ul><ul><li>Someone with neglect can see an entire letter enough to say what it is. </li></ul><ul><li>The same person ignores the left half when asked to cross out all the letters that compose a word. </li></ul>
    60. 60. Attention <ul><li>Several procedures can increase attention to the neglected side: </li></ul><ul><ul><li>telling the person to pay attention to the left side. </li></ul></ul><ul><ul><li>telling the person to look left while feeling an object with the left hand or hearing a sound from the left side. </li></ul></ul><ul><li>A touch stimulus briefly increases attention to one side of the body or the other. </li></ul><ul><li>Crossing of the hands in front of the body also decreases neglect to the left side. </li></ul>
    61. 61. Fig. 14-20, p. 444
    62. 62. Attention <ul><li>Many patients with spatial neglect also have deficits with spatial working memory and with shifting attention, even when location is irrelevant. </li></ul><ul><li>Thus, problems associated with neglect extend to many aspect of attention rather than simply the left-right dimension. </li></ul>
    63. 63. Attention <ul><li>Attention-Deficit Hyperactivity Disorder (ADHD) is characterized by the following: </li></ul><ul><ul><li>Attention deficits (distractibility). </li></ul></ul><ul><ul><li>Hyperactivity (fidgetiness). </li></ul></ul><ul><ul><li>Impulsiveness. </li></ul></ul><ul><ul><li>Mood swings. </li></ul></ul><ul><ul><li>Short temper. </li></ul></ul><ul><ul><li>High sensitivity to stress. </li></ul></ul><ul><ul><li>Impaired ability to make and follow plans. </li></ul></ul>
    64. 64. Attention <ul><li>ADHD affects social behavior and school performance. </li></ul><ul><li>Some have occupational problems and antisocial behaviors in adulthood. </li></ul><ul><li>Estimates range from 3%-10% of children </li></ul><ul><li>Twice or three times as likely in males. </li></ul><ul><li>Research is complicated by the ability to make reliable diagnoses. </li></ul>
    65. 65. Attention <ul><li>Three example of tasks which people with ADHD differ: </li></ul><ul><ul><li>“The choice delay task” - more likely than others to choose a smaller but quicker reward (impulsiveness). </li></ul></ul><ul><ul><li>“The stop signal task” - difficulty inhibiting behaviors. </li></ul></ul><ul><ul><li>“The attentional blink task” - indicates trouble controlling attention and difficulty shifting it when needed. </li></ul></ul>
    66. 66. Attention <ul><li>Twin studies suggest fairly high heritability (Thapar et al., 2003). </li></ul><ul><ul><li>Several genes have been identified which influence performance on tests of attention. </li></ul></ul><ul><li>ADHD probably depends on multiple genes as well as environmental influences. </li></ul><ul><li>Probability of ADHD is elevated among children of women who smoked cigarettes during pregnancy. </li></ul>
    67. 67. Attention <ul><li>Structural brain differences include a smaller than average prefrontal cortex and cerebellum. </li></ul><ul><ul><li>Cerebellar dysfunction is known to be associated with difficulty switching attention. </li></ul></ul><ul><li>Structural differences in the brain are small and inconsistent between cases. </li></ul><ul><ul><li>Brain scans do not provide reliable results for diagnoses. </li></ul></ul>
    68. 68. Attention <ul><li>The most common treatment for ADHD is stimulant drugs or amphetamines. </li></ul><ul><ul><li>Example: methylphenidate/Ritalin. </li></ul></ul><ul><li>Stimulant drugs increase attentiveness, improve school performance and social relationships, and decrease impulsiveness. </li></ul><ul><li>Also improve scores on laboratory tests, such as the “stop signal task”. </li></ul><ul><li>Justifying the benefits derived from taking the drugs is a complex and controversial issue. </li></ul>
    69. 69. Attention <ul><li>Amphetamines and methylphenidate increase the availability of dopamine to the postsynaptic receptors. </li></ul><ul><li>Maximum benefit occurs 1 hour after ingestion and benefits last for a few hours. </li></ul><ul><li>Several studies have found that stimulant drugs enhance certain aspects of learning and attention for all people, not just those with ADHD. </li></ul>
    70. 70. Attention <ul><li>Behavioral techniques are available as supplements or substitutes for stimulant drugs: </li></ul><ul><ul><li>Reduce distractions. </li></ul></ul><ul><ul><li>Use lists, calendars, and other organizational techniques. </li></ul></ul><ul><ul><li>Practice strategies to pace yourself. </li></ul></ul><ul><ul><li>Learn to relax; tension and stress can magnify attention deficits. </li></ul></ul>

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