tone and prosody mental lexicon/lexical level

1. ALLPPT.com _ Free PowerPoint Templates, Diagrams and Charts
Page: 185-197
By p.baghrepour
The cognitive neuroscience
of human communication
CHAPTER 8
IN THE NAME
OF GOD

2. Production and perception of prosody
1. Language prosody : understanding ambiguities at the word or sentence
2. Emotional (affective): reveals condition, attitudes, and mood of the speaker
distinction of sentences/word
* Prosody = tone +duration+ intensity (+pause)
TONE AND PROSODY

3. Neural Bases Of Production And The Perception Of Prosody
4 hypotheses :
1. The right hemisphere is dominant for all types of prosody.
2. The right hemisphere is dominant for affective (emotional) prosody, whereas the left hemisphere
is dominant for linguistic prosody.
3. Duration, tone, and intensity are lateralized differently.
4. Prosody is a subcortical activity, not lateralized to either hemisphere.

4.  Patients with left-hemisphere damage
-difficulty understanding words
-no problems with interpreting emotional
(affective) prosody
 right hemisphere–damaged patients
-comprehend linguistically expressed meaning
-great difficulty distinguishing among utterances
on the basis of their affective prosody
 difficulty in recognizing faces expressing fear.
 Aprosodia monotonous speech
no variation in F0
unnaturally duration/accents
equal pauses between words
robot-like quality
diminished reactions to emotion

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different prosodic parameters may be affected selectively both after
left- and right-hemisphere damage
 left : temporal features, such as sequence and duration.
 right :spectral information/frequency= distinguishing different emotions

6. Patients suffering from right-hemisphere:
- poor affective prosody is not to be equated with lack of emotions—it is a m
anifestation of their inability to express emotions.
- insufficient use of intonation in speech/ unnaturally flat and monotonous/
small variation in F0/ Difficulties linguistic prosody comprehension

7. neural networks in processing prosody:
• functions is not based on the dichotomies such as verbal/nonverbal or linguistic /affective
left hemisphere: time-dependent or sequential processing.
(sequencing, duration of elements, and pauses between them)
right hemisphere: independent of temporal spectral information.
(pitch and harmonic structure)

8. LEXICAL LEVEL AND MENTAL LEXICON
the left hemisphere is dominant during automatic processing, when fast processing of f
amiliar, denotative meanings is required.
left hemisphere–damaged patients (deficits in denotative aspects of meaning) regularly chose
the connotative option.
semantic information in the right hemisphere is probably activated only when controlled
attention is required—in other words, when we are not happy
with the central meaning of the word and have to make additional effort to access an alt
ernate meaning instead.
Right hemisphere–damaged patients (deficits in connotative aspects of meaning) more
frequently chose the denotative variant.

9. Semantic concepts activated by the
Left hemisphere:
- typically familiar
- dominant
- closely interrelated
- with substantial semantic overlap.
- during automatic processing
- Fast
- activation of dominant (central) me
anings.
right hemisphere:
- less familiar
- connotative
- alternate
- loosely associated
- less semantic overlap.
- functions better under controlled processing
- slower and weaker
- activation of alternate meanings.

10. Problems in semantic processing typical of right hemisphere–damaged
patients may be manifested as:
1. capacity to provide appropriate category names for presented groups of objects
2. capacity to determine whether pairs of objects are related.
3. On tests of verbal fluency, compared with healthy controls:
a. They produce more central (prototypical, dominant) items.
b. They generate more items with common properties within the
semantic category.
c. They have more difficulties with goal-derived than with semantic categories
(things to take to the beach vs. beach towel, ball, sun lotion).
diminished capacity to solve lexical ambiguities

11.  Since normal human communication is extremely fast (an adult native speaker of any given la
nguage can recognize and produce about three words per second)
 mental lexicon must be organized so that it enables efficient
and quick access to stored information

12. the lexicon is organized like some sort of a network:
1. Mental lexicon is adaptable. We learn new words throughout our lives,but we also forget some
of the words we have learned at some point and stopped using.
2. The words used more frequently are retrieved faster than the ones used less frequently.
3. Words that are pronounced similarly to many other words are retrieved more slowly than the on
es whose pronunciation is unique or in some aspect special.
4. Semantically related words are stored closer to each other in the network. This was revealed by t
he effect of priming (a target word is recognized faster if the prime is a semantically related word);
this is explained by the prime activating a set of expected words, and if the target word is part of t
hat set it will take less time to respond to it than if it were not.

13. Typical semantic errors in brain-damaged patients support the notion of network
organization:
1. Semantic paraphasias—within-category substitution of words (e.g., snow
instead of sleet).
2. Difficulties in determining appropriate semantic categories—the patient
does not know that birch belongs to trees.
3. Inappropriate use of superordinate terms—bird in response to the picture
of a pigeon.

14. Word Recognition
- Words are processed through three stages: lexical access, lexical selection, and
lexical integration.
- Lexical access follows perceptual analysis of the input signal and is dependent on it.
- Visual input : dual route direct: from orthography to word form
indirect: mediated by phonological encoding

15. The dual-route model is supported by evidence from patients suffering from
acquired dyslexia:
a) phonological (deep) dyslexia:
- cannot read nonsense words
- reading irregular meaningful words
- rely exclusively on the direct route and are therefore incapable of reading words that
do not exist in their mental lexicon.
- with semantic paraphasias.
b) surface dyslexia:
read all words using the indirect route, incorrect pronunciation of irregular words.

16. Auditory processing
Auditory data are processed in the auditory cortex first (Heschl gyrus), to be forward
ed to the superior temporal gyrus. (At this point there are no differences between sp
eech and nonspeech signals). The difference emerges for the first time in the neighb
oring superior temporal sulcus, but at this level the lexico-semantic processing has n
ot yet started. From here the information is transmitted to the middle and inferior
temporal gyrus, where phonological and lexico-semantic processing takes place.
The final analysis is carried out in the angular gyrus. Greater activity in the left
hemisphere than in the right is usually recorded at the point where the phonological
and lexico-semantic processing begins.

17. Visual processing
In visually presented words, the initial processing is no different than processin
g of any visual stimuli, including nonlinguistic ones. It takes place in the prima
ry and the secondary visual cortex in the occipital lobes of both hemispheres.
Letter identification involves the occipitotemporal lobe (predominantly in the l
eft hemisphere), but also the middle temporal gyrus—more so in words than i
n nonwords. During pronunciation, the left inferior frontal gyrus, including the
ventral part of Broca’s area, is activated.

18. Conclusions:
(a) lexical access by means of visual input (direct route) involves posterior parts of both
temporal lobes
(b) lexical access mediated by phonological encoding (indirect route) comprises a left-lat
eralized posterioranterior loop that includes the fusiform gyrus, involved in sublexical
grapheme processing (posterior part), and the inferior frontal gyrus, involved in phon
ological processing (anterior part)
(c) regardless of the access route, the retrieved lexico-semantic information is further
processed in the inferior part of the left prefrontal lobe.