The document discusses lateralization of brain function and language areas. It explains that in most humans, the left hemisphere of the brain contains specialized language areas. It then describes how physicians in the 1800s like Broca and Wernicke discovered two key language areas by studying patients with language impairments. Broca's area in the frontal lobe controls speech production, while Wernicke's area in the temporal lobe is involved in speech comprehension. Damage to these areas can cause different types of aphasia with distinct language symptoms.

1. SPEECH AND THE BRAIN

2. Lateralization
 The brain is divided into two halves, a left
hemisphere and a right hemisphere. This is called
lateralization

3. Lateralization
 In human beings, the left hemisphere that usually
contains the specialized language areas.
 This holds true for 97% of right-handed people,
about 19% of left-handed people have their
language areas in the right hemisphere and as
many as 68% of them have some language
abilities in both the left and the right hemispheres.

4. Lateralization

5. Lateralization
 Lateralization was
first discovered in
the 1800's by
physicians such
as Paul Broca and
Carl Wernicke
 These physicians
found damage to
particular areas of
the brain now
named after them,
and these areas
were consistently
on the left
hemisphere.

6. Lateralization
 Most recently, researchers have taken advantage
of the huge advances made in brain imaging. In
particular, the PET scan
 Since active areas of the brain use more energy,
and therefore more glucose, they release more
radiation, which the computer translates into
"warmer" colors such as yellow and red.
 Areas that are less active are shown with "cooler"
colors such as green and blue.
 Certain areas of the left hemisphere were more
active while people were engaged in linguistic
activities.

7. Lateralization

8. Introduction to Broca and
Wernicke’s Areas
broca and wernicke areas

9. Broca’s Area

10. Broca’s Area
 The first language area within the left hemisphere
to be discovered is called Broca's Area, after Paul
Broca.

11. Broca’s Area
 Broca was a French neurologist who had a
patient with severe language problems.
 He could understand the speech of others with
little difficulty, but the only word he could produce
was "tan."
 Because of this, Broca gave the patient the
pseudonym "Tan.”
 After the patient died, Broca performed an
autopsy, and discovered that an area of the
frontal lobe, just ahead of the motor cortex
controlling the mouth, had been seriously
damaged.

12. Broca’s Area
 Physicians called the inability to speak aphasia,
and the inability to produce speech was therefore
called Broca's aphasia, or expressive aphasia.
 sarah scott - broca's aphasia
 sarah scott - 3 years later

13. Broca’s Area
 Someone with this kind of aphasia has little
problem understanding speech.
 But when trying to speak themselves they are
capable only of slow, laborious, often slurred
sequences of words.
 They don't produce complete sentences, seldom
use regular grammatical endings such as -ed for
the past tense, and tend to leave out small
grammatical words.

14. Broca’s Area
 It turns out that Broca's area is not just a matter of
getting language out in a motor sense, though.
 It seems to be more generally involved in the
ability to deal with grammar itself, at least the
more complex aspects of grammar.
 For example, when they hear sentences that are
put into a passive form, they often
misunderstand: If you say "the boy was slapped
by the girl," they may understand you as
communicating that the boy slapped the girl
instead.

15. Wernicke’s Area

16. Wernicke’s Area
 The second language
area to be discovered
is called Wernicke's
Area, after Carl
Wernicke, a German
neurologist.

17. Wernicke’s Area
 Wernicke had a patient who could speak quite
well, but was unable to understand the speech of
others.
 After the patient's death, Wernicke performed an
autopsy and found damage to an area at the
upper portion of the temporal lobe, just behind the
auditory cortex.
 He correctly hypothesized that this area was
responsible for speech comprehension.

18. Wernicke’s Area
 This kind of aphasia is known
as Wernicke's Aphasia, or
receptive aphasia.
 When you ask a person with
this problem a question, they
will respond with a sentence
that is more or less
grammatical, but which contains
words that have little to do with
the question or, for that matter,
with each other.
 Strange, meaningless, but
grammatical sentences come
forth, a phenomenon called

19. Wernicke’s Area
 Like Broca's area is not just about speech
production, Wernicke's is not just about speech
comprehension.
 People with Wernicke's Aphasia also have
difficulty naming things, often responding with
words that sound similar, or the names of related
things, as if they are having a very hard time with
their mental "dictionaries.“
 wernicke's aphasia - amelia carter