Carl Wernicke

4 Key excerpts on "Carl Wernicke"

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  Neuropsychology

  A Textbook of Systems and Psychological Functions of the Human Brain

  • Stuart J. Dimond(Author)
  • 2013(Publication Date)
  • Butterworth-Heinemann

    (Publisher)

  Wernicke (1874) also singled out the cortex of the posterior superior temporal area as of importance. He described cases in which not only speech but also comprehension was impaired. As we have seen, post-mortem material had shown a different location in these cases from that described previously by Broca. Bogen and Bogen (1976) discuss the considerable variation and, indeed, confusion in the anatomical description of Wernicke's area together with the problem of specifying the functions of this region. They suggest that we need a picture resembling a topographical map that shows a probability distribution and a map that shows the likelihood at any particular locus of a comprehension deficit from a lesion at that locus. After Wada (1949) introduced the intracarotid sodium amytal test, it became possible to compare the functions of the two cerebral hemispheres by this means. Branch, Milner and Rasmussen (1964) tested the language of 123 patients who were required to name objects and to count during the injection. The majority of right-handed subjects had speech on the left side. When clinical evidence was found of an injury to the left hemisphere at birth or in early life, speech was found to be on the right side in approximately two-thirds of the left-handed patients. 330 Language Penfield and Roberts (1959) did not completely uphold the view of rigidly defined anatomical speech areas. However, they were able to obtain through electrical stimulation of the brain responses from regions regarded as the classical speech areas, but also from a third area in the supplementary motor area anterior to that controlling the movements of the foot. This finding was also supported by Russell and Young (1969). There is a large literature on the effects of left-hemisphere damage on language, to which we return in a later section.

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  The Science of Learning and Development in Education

  A Research-based Approach to Educational Practice

  • Minkang Kim, Derek Sankey(Authors)
  • 2022(Publication Date)
  • Cambridge University Press

    (Publisher)

  PART 1 THE SCIENCE OF LEARNING AND DEVELOPMENT IN THE TWENTY-FIRST CENTURY 116 The role of brain lesions in understanding language Many of the early discoveries about the human brain have come from people who have suffered brain damage (lesions) and subsequently lost a particular ability. In regard to lan- guage, early discoveries were related to two different condi- tions that go by the general name of aphasia (or dysphasia). In the nineteenth century, the French neuroanatomist Paul Broca (1824–1880) studied two patients who had lost the ability to speak words, though they could still understand them. This is often referred to as expressive aphasia (or Broca’s aphasia). When they died it was discovered by autopsy that they had lesions in Brodmann areas 44 and 45, in the left hemisphere of the brain, which also became known as Broca’s area (see also Chapter 4) – but see the note on brain specialisation, below. A different from of aphasia, often referred to as Wernicke’s aphasia, was identified by the German neuroanato- mist Carl Wernicke (1848–1905). This condition, in which a patient loses the ability to un- derstand spoken or written language, results from lesions in both areas 22 and 39 in the left hemisphere, also known as Wernicke’s area (Figure 5.1). The study of brain lesions has assisted our understanding of language, but there are some important caveats that need to be noted. Most naturally occurring lesions, such as those resulting from a stroke, are not neatly restricted to small areas of the brain devoted to very specific tasks, such as recognising the orientation of lines in reading, but tend to be more widespread. Relating a particular lesion to a specific skill may therefore not be very precise and subsequent research is required to identify the actual site of impairment.

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  Introduction to Psycholinguistics

  Understanding Language Science

  • Matthew J. Traxler(Author)
  • 2011(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Broca’s area ) was necessary for fluent, meaningful speech in normal individuals. This conclusion is based on a fundamental tenet of aphasiology: If part of the brain is damaged, and a person subsequently is unable to do some task (like speak or understand sentences), then the part of the brain that was damaged must have participated in the performance of that task. If a group of people all have the same symptoms, and all have brain damage in the same place, then that part of the brain is necessary for the successful performance of the task.

  Figure 13.1 The left hemisphere of Leborgne and Lelong’s brains. Closeup of Broca’s area appears in the right-hand pictures. (From Dronkers et al., 2007)

  A few years after Broca published his studies of the patients Leborgne and Lelong, Carl Wernicke4 described a different language syndrome, based on two patients, Susanne Adam and Susanne Rother, who had a pattern of symptoms much different than those exhibited by Broca’s patients (Eling, 2006).5 These patients could speak and hear, but they had difficulty understanding both spoken and written language, and their spoken output was also marked by the use of neologisms (new, made-up words) and by semantic anomalies. One of the two patients appeared to understand “absolutely nothing” (Mathews, Obler, & Albert, 1994, p. 447). This latter patient was autopsied after she died, and she was found to have a lesion in the posterior (rear) portions of her brain, near the place where the temporal, parietal, and occipital lobes meet. She also had widespread loss of tissue in her cerebral cortices. No information about the existence or location of a lesion is available for the other patient.

  After reviewing Susanne Rother’s lesion location and both patients’ patterns of comprehension and speech output, Wernicke formulated his theory of “sensory” and “motor” aphasia. Wernicke proposed that posterior regions of the brain stored “remembered images,” while frontal regions stored “impressions of action” (Lanczik & Keil, 1991, p. 174). Wernicke proposed that there are two kinds of “remembered images” that are critical for language comprehension. One set of “images” reflects the phonological (sound) information associated with words, while the other reflects the conceptual/semantic (meaning) information. Hence, Wernicke viewed Broca’s aphasia as reflecting a failure of the (motor) movement system (hence, motor aphasia), while patients with posterior damage suffered from dysfunction in the perceptual-memory system (hence, sensory aphasia). More specifically, they suffered from an inability to retrieve a trace of the “sound image” in their attempts to comprehend language. As such, the patients’ problems did not reflect an overall reduction in intellect or the ability to think. Rather, aphasia reflected brain damage interfering with language comprehension and production processes; and brain damage in the language centers did not adversely affect patients’ ability to think.6

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  Your Brain, Explained

  What Neuroscience Reveals about Your Brain and its Quirks

  • Marc Dingman(Author)
  • 2019(Publication Date)
  • Nicholas Brealey Publishing

    (Publisher)

  Like Leborgne, patients with Broca’s aphasia have difficulty forming words. When they do get words out, it’s often a laborious process, and frequently words—or parts of words like the endings of nouns and verbs—are omitted. If asked to describe a trip to the grocery store, these patients might say something like, “Go . . . store” with a long pause between the two words.

  Wernicke gets an area of his own

  Scientists in Broca’s day were reluctant to accept the idea that Broca’s area is specialized to handle a task like language production, especially since supporting this hypothesis also meant accepting that the two cerebral hemispheres are not carbon copies of one another—which flew in the face of the dogma of the time.

  About 15 years after Leborgne had first been put under Broca’s care, however, a young German physician named Carl Wernicke provided some additional backing to the idea that language resides in the left hemisphere. Wernicke made a discovery that was akin to Broca’s: he found an area in the left hemisphere that, when damaged, resulted in a characteristic speech deficit.

  When patients experience damage to what has come to be known as Wernicke’s area , however, they develop language difficulties that in some ways are the converse of Broca’s aphasia. Patients with Wernicke’s aphasia have no trouble generating speech. In fact, words flow out of their mouths effortlessly, and typically they can speak with the rhythm and intonation of a healthy person. But the words they produce are often meaningless.

  These patients speak gibberish, substituting one word for another, mixing up sounds within words, or even creating new words altogether. For example, a Wernicke’s aphasia patient trying to describe going to the grocery store might say something like, “Went to the studgel, see? To get the gocksee. And even when I get the gocksee, I have to get it into the bar. It’s hard to get that.” The patient is trying to say that he went to the store to get groceries, and then had to get the groceries into his car. But he has replaced “store” and “groceries” with neologisms

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