Transcript ling411-21 - Rice University

Ling 411 – 21
Interpreting Neurolinguistic Evidence
Careless thinking and critical thinking
Schedule of Presentations
Tu Apr 13
Delclos
Planum Temp
McClure
Gram.-Broca
Th Apr 15
Tu Apr 20
Th Apr 22
Banneyer
Categories
Ezzell
Lg Dev. (Kuhl)
Ruby Tso
Writing
Rasmussen
2nd language
Bosley
Synesthesia
Brown
Lg&Thought
Gilcrease-Garcia
AG
Roberts
MTG
Koby
Music
Mauvais
LH-RH anat.
Tsai
Tones
Shelton
Thalamus
Delgado
Amusia
Joyce Liu
RH functions
Interpreting Linguistic Evidence
Careless thinking and critical thinking
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Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Retrieval of words, meanings
• Communication between subsystems
Wernicke’s area and speech production
Examples of careless thinking:
Steven Pinker:
Wernicke’s area …was once thought to underlie language
comprehension. But that would not explain why the
speech of these patients sounds so psychotic.
The Language Instinct (1994)
Friedemann Pulvermüller:
…patients with Wernicke’s aphasia have difficulty
speaking…. These deficits are typical…and cannot be
easily explained by assuming a selective lesion to a
center devoted to language comprehension.
The Neuroscience of Language (2002)
Perceptual structures in motor production
 Perceptual structure is used in two ways
Planning (e.g. visualizing while painting)
2. Monitoring
1.
 Examples
•
•
•
•
Phonological recognition in speech production
 Cf. Wernicke’s aphasia
Painting
Musical production
Baseball, soccer, tennis, etc.
Interpreting Linguistic Evidence
Careless thinking and critical thinking
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Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Retrieval of words, meanings
• Communication between subsystems
Broca’s area and speech production - I
Careless thinking previously considered:
John Pinel (Biopsychology textbook):
Surgical excision of Broca’s area failed to
result in loss of speech production (after
recovery from surgery)
Broca’s Area: Not for Speech Production?
Surgical excision
was done in two
stages. Following
completion of
the second stage,
no speechrelated problems
were reported.
Patient D.H.
John Pinel, Biopsychology (1990:560),
Adapted from Penfield & Roberts, 1959
Broca’s Area: Not for Speech Production?
What Pinel
neglects to
mention, but it is
in Penfield &
Roberts: Patient
D.H. was a young
boy who had
been having
seizures,
originating in this
part of his brain.
Patient D.H.
John Pinel, Biopsychology (1990:560),
Adapted from Penfield & Roberts, 1959
More on patient D.H.
 Eighteen years old at time of surgery
 Had suffered from seizures causing an
inability to speak from the age of 3 1/2
 Apparently, “the congenital abnormality
had caused displacement of function”
Penfield & Roberts
Speech and Brain Mechanisms
(1959: 163)
Broca’s area and speech production - II
 Influential paper by Alexander et al. (1990)
 Motivation for the study
• Maybe it’s not just Broca’s area damage that is
•
responsible for some of the symptoms of
“Broca’s aphasia”
Maybe some of them result instead from
damage to neighboring areas
 They studied a group of patients
 Distinguished 3 subtypes of Broca’s aphasia
Three subtypes in Alexander study
1. Impaired speech initiation
•
•
Symptom traditionally attributed to
transcortical motor aphasia
Area of damage: frontal operculum
•
Area of damage: lower primary motor cortex
2. Disturbed articulatory function
3. The classical Broca’s aphasia syndrome
• More extensive damage
Type I
 One patient
 Area of damage
• Frontal operculum
• Adjacent middle frontal gyrus
• Subjacent subcortical white matter
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Speech quality normal
Normal repetition
Speech terse and delayed in initiation
Speech grammatically correct!
Anomia and semantic paraphasias
Insula and opercula
View with opercula pulled back to expose insula
1.Short gyri of insula
2.Long gyrus of insula
3.Superior temporal gyrus
4.Circular sulcus of insula
5.Frontal operculum
6.Frontoparietal operculum
7.Temporal operculum
Original Brodmann Map - Colorized
Outlines - with Functional Attribution
Type I – critical appraisal
 Area of damage
• Frontal operculum
• Adjacent middle frontal gyrus
• Subjacent subcortical white matter
 Symptoms
• Speech quality normal
• Normal repetition
• Speech terse and delayed in initiation
• Speech grammatically correct!
• Anomia and semantic paraphasias
 The symptoms are those of transcortical
motor aphasia
Type I (cont’d)
(from Alexander study)
 Other relevant studies
• Patients with frontal operculum lesion but with
•
•
•
primary motor cortex spared
Symptoms like those usually called TCMA
Speech output
 “Terse, laconic”
 Grammatical, sentence-length
 Semantic paraphasias
 Normal articulation
Evidently, damage to subjacent white matter “is
essential for lasting aphasia after lesions in the
frontal operculum” (Alexander et al. 1990” 357)
Type I (cont’d)
(from Alexander study)
 Other relevant studies
• Patients with frontal operculum lesion but with
•
•
•
primary motor cortex spared
Symptoms like those usually called TCMA
Speech output
 “Terse, laconic”
 Grammatical, sentence-length
 Semantic paraphasias
 Normal articulation
Evidently, damage to subjacent white matter “is
essential for lasting aphasia after lesions in the
frontal operculum” (Alexander et al. 1990” 357)
Type I (cont’d)
(from Alexander study)
 Other relevant studies
• Patients with frontal operculum lesion but with
•
•
•
primary motor cortex spared
Symptoms like those usually called TCMA
Speech output
 “Terse, laconic”
 Grammatical, sentence-length
 Semantic paraphasias
 Normal articulation
Evidently, damage to subjacent white matter “is
essential for lasting aphasia after lesions in the
frontal operculum” (Alexander et al. 1990” 357)
Type II
 Patients 2-6 in Alexander et al. (1990) study
 Areas of damage
•
•
•
•
Frontal operculum
Lower primary motor cortex
Anterior insula
White matter deep to these regions
•
•
Except for initiation struggle
Except for patient #6: single word utterances
 Right facial paresis and mild right hand weakness
 Defective articulation
 Sentence-length grammatically normal utterances!
Type II (cont’d)
 Other studies support the attribution of
dysarthria to primary motor cortex
• Patients with
•
 Small shallow lesions in lower motor cortex
 Frontal operculum not involved
Labels that have been used
 Aphemia
 Cortical dysarthria
 Apraxia
(Alexander et al. 1990: 357)
Type III
 Patients 7-9 in Alexander et al. (1990) study
 Areas of damage:
• Lower motor cortex and/or subjacent white matter
• Anterior superior insula
• Lateral putamen (a nearby subcortical structure)
• Frontal operculum spared
 Right central facial paresis
 Aphasia symptoms similar to Type II
• Including absence of agrammatism
 Phonemic paraphasias in repetition
 One patient (#9) had virtually no speech output
Receptive agrammatism
 “All cases had some impairments in
auditory comprehension at the level of
complex sentences or multistep commands.”
(Alexander et al. 1990: 360)
 Indicates short-term memory deficit
Confounding factors
 “We did not evaluate any of the patients in
the acute phase of their illnesses; all were
referred to the Boston VAMC for speech
and language therapy.” (Alexander et al. 1990:
353)
 Localization of lesions was done by CT scan
– not sensitive enough to detect small
areas of damage (360)
The importance of plasticity
 “In the acute phase, these patients may
have traditional, nonfluent aphasia –
articulation impairment, prosodic
impairment, and agrammatical, shortened
utterances. The evolved disorder is,
however, much less severe than that;
grammatical, sentence-length utterances
return, albeit still labored and paraphasic
and with speech impairment.”
(Alexander et al. 1990:361)
 Recovery is not so good if extensive white
matter involvement
Another study
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Taubner, Raymer, and Hellman 1999,
“Frontal-opercular Aphasia”: 5 types:
1. “Verbal akinesis” like Trans-cortical motor
aphasia – supplementary motor area and
cingulate gyrus
2. Disorders of grammar – pars opercularis
3. Phonemic disintegration – primary motor
cortex
4. Defects of lexical access – pars triangularis
and adjacent frontal cortex
5. Mixed defects
Proceed with Caution!
 How should we interpret the results of the
Alexander study?
 Some researchers have concluded that
damage to Broca’s area is not responsible
for Broca’s aphasia after all
• Reason: No lasting impairment of speech
production if only Broca’s area is damaged,
without white matter involvement
 Alternative explanation?
Alternative explanation
 Plasticity
 N.B. Patients were examined only after
they had had time to recover, not in the
acute phase
 The evidence indicates that
• Functions of Broca’s area can be partly regained
•
by recruitment of neighboring area(s)
But: such recovery is impaired if there is also
damage to subjacent white matter
Interpreting Linguistic Evidence
Careless thinking and critical thinking






Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Retrieval of words, meanings
• Communication between subsystems
Friederici Fig. 1
Syntactic networks
in the human brain.
(a) Depicts the two
neural networks for
syntactic processing
and their frontotemporal
involvement
(function)
schematically.
(b) Shows fiber tracting as revealed by DTI (structure) in
an individual subject: top right, with the starting point
(green dot) being BA 44 and bottom right, with the starting
point (blue dot) being the frontal operculum.
Friederici Figure 2
Fiber tracts between Broca's and Wernicke's area. Tractography
reconstruction of the arcuate fasciculus using the two-region of interest
approach. Broca's and Wernicke's territories are connected through
direct and indirect pathways. The direct pathway (long segment shown in
red) runs medially and corresponds to classical descriptions of the
arcuate fasciculus. The indirect pathway runs laterally and is composed
of an anterior segment (green), connecting Broca's territory and the
inferior parietal cortex (Geschwind's territory), and a posterior segment
(yellow), connecting Geschwind's and Wernicke's territories.
Wernicke’s & Broca’s areas for syntax?
Combining functional MRI and DTI, two of these pathways were defined as
being relevant for syntactic processes [44]. Functionally, two levels of
syntactic processing were distinguished, one dealing with building a local
phrase (i.e. a noun phrase consisting of a determiner and a noun ‘the boy’)
and one dealing with building complex, hierarchically structured sequences
(like embedded sentences ‘This is the girl who kissed the president’). DTI
data [44] revealed that the frontal operculum supporting local phrase
structure building [14] and [44] was connected via the UF to the anterior
STG which has been shown to be involved in phrase structure building as
well [14]. The dorsal pathway connects BA 44 which supports hierarchical
structure processing [42] and [45], via the SLF to the posterior portion of
the STG/STS, which is known to subserve the processing of syntactically
complex sentences 51 I. Bornkessel et al., Who did what to whom? The
neural basis of argument hierarchies during language comprehension,
Neuroimage 26 (2005), pp. 221–233. Article | PDF (300 K) | View Record in
Scopus | Cited By in Scopus (53)[51]. This latter network was, therefore,
taken to have a crucial role in the processing of syntactically complex,
hierarchically structured sentences.
(Friederici 2009, p. 179)
Critique of Friederici paper by Weiller
et al. (August 2009)
Friederici claims the dorsal pathway ‘to be crucial for the
evolution of human language, which is characterized by
the ability to process syntactically complex sentences’. …
As suggested in our paper, ‘the involvement of the dorsal
stream for processing of complex syntactic operations
might be partially explained as a result of an increase in
syntactic working memory load’ [2]. Syntax and memory
are hard to keep apart.
Trends in Cognitive Sciences vol. 13, Issue 8,
September 2009. pp. 369-370.
Hickok on phonological working memory
“… Broca’s area and the SMG are involved in speech
perception only indirectly through their role in phonological working memory which may be recruited during
the performance of certain speech perception tasks.”
Hickok 2000: 97
“The sound-based system interfaces not only with the
conceptual knowledge system, but also with frontal
motor systems via an auditory-motor interface system
in the inferior parietal lobe. This circuit is the primary
substrate for phonological working memory, but also
probably plays a role in volitional speech production.
Hickok 2000: 99
Interpreting Linguistic Evidence
Careless thinking and critical thinking






Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Retrieval of words, meanings
• Communication between subsystems
Impairment of nominal concepts
 Access to nominal concepts is impaired in
extra-sylvian sensory aphasia
 Type I – Damage to temporal-parietaloccipital junction area
•
•
•
•
I.e., lower angular gyrus and upper area 37
Poor comprehension
Naming strongly impaired
Semantic paraphasia
•
•
•
•
Variable ability to comprehend speech
Naming strongly impaired
Few semantic paraphasias
Many circumlocutions
 Type II –Damage to upper angular gyrus
2 Cases of Rapp & Caramazza (1995)
 E.S.T. (901b) – Left temporal damage
• “Meaning spared, couldn’t say the word”: R&C
 J.G. (902a) – Left posterior temporal-parietal
• Meaning spared, couldn’t spell the word
correctly, but phonological recognition okay
Cf. Rapp & Caramazza,
Disorders of lexical processing
and the lexicon (1995)
Patient E.S.T.
(Rapp&Caramazza 1995:901b)
 Left temporal damage
 Shown picture of a snowman
• Unable to name it
• “It’s cold, it’s a ma… cold … frozen.”
 Shown picture of a stool
• “stop, step … seat, small seat, round seat, sit
on the…”
 Shown written form ‘steak’
• “I’m going to eat something … it’s beef … you
can have a [së] … different … costs more …”
 What can we conclude?
Assessment of E.S.T.
by Rapp & Caramazza
 Responses of E.S.T. indicate awareness of
the meanings (SNOWMAN, STOOL, STEAK)
 Therefore, “meaning is spared” (according to
Rapp & Caramazza)
Warning: Proceed with caution
 The assumption of Rapp&Caramazza is easy
to make
• I.e., that meaning (conceptual information) is
spared
 But there’s more to this than meets the eye!
 As we have seen, conceptual information is
widely distributed
 We only have evidence that some of the
conceptual information is spared
Patient E.S.T. – a closer look
 Left temporal damage
 Picture of a snowman
• “It’s cold, it’s a ma… cold … frozen.”
 Picture of a stool
• “stop, step … seat, small seat, round seat, sit
on the…”
 Written form ‘steak’
• “I’m going to eat something … it’s beef … you
can have a [së] … different … costs more …”
 These are not definitions
 This is connotative information
• Vague semantic notions about the meanings
Compare patient J.G. (902a)
 Damage: Left posterior temporal-parietal
 Meaning spared, couldn’t spell the word
correctly, but phonological recognition okay
• digit:
•
 D-I-D-G-E-T
 “A number”
thief:
 T-H-E-F-E
 “A person who takes things”
 These are actual definitions
The Role of RH in semantics
 Conceptual information, even for a
single item, is widely distributed
• A network
• Occupies both hemispheres
 RH information is more connotative
• LH information more exact
Connotative information in RH
 Tests on patients with isolated RH resulting from
callosotomy
 RH has information about (many) nouns and verbs
•
Not as many as in LH
 Semantic information differently organized in RH
 Zaidel (1990): “… the right hemisphere is
characteristically connotative rather than
denotative … . The arcs [of the semantic network]
connect more distant concepts … and the
organizing semantic relationships are more loosely
associative and dependent on experience” (125)
Baynes & Eliason, The visual lexicon: its access and
organization is commissurotomy patients (1998)
Semantic information: E.S.T. and J.G.
 Patient J.G. – real definitions
• digit: “A number”
• thief: “A person who takes things”
 Patient E.S.T. – connotative information
• snowman: “It’s cold, it’s a ma… cold … frozen.”
• stool: “ … seat, small seat, round seat, sit on
•
the…”
steak: “I’m going to eat something … it’s beef …
you can have a [së] … different … costs more …”
Conclusion about E.S.T.
 RH semantic information is intact
 LH semantic information is wiped out
 Phonological information is spared in both
hemispheres
 Question: Why can’t the RH semantic
information be conveyed to LH phonology?
Corpus Callosum
(revealed by excision of
top of right hemisphere)
Corpus
Callosum
Interpreting Linguistic Evidence
Careless thinking and critical thinking






Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Retrieval of words, meanings
• Communication between subsystems
Mirror Neurons
 “What makes them so smart?”
 (already considered)
• It’s a matter of hierarchical organization
Implications of hierarchical organization
 Nodes at a high level in a hierarchy may
give the appearance of being very “smart”
 This appearance is a consequence of their
position — at top of hierarchy
 As the top node in a hierarchy, a node has
the processing power of the whole
hierarchy
• Grandmother nodes
• Mirror neurons
• Compare:
 The general of an army
 The head of a business organization
Interpreting Linguistic Evidence
Careless thinking and critical thinking

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



Wernicke’s area and speech production
Broca’s area and speech production
Broca’s area and Wernicke’s area in syntax
The meanings of words
“Mirror neurons” – very smart?
Invoking the computer metaphor
• Representation of information
• Retrieval of words, meanings
• Communication between subsystems
The brain and the computer
Conference abstract, March 28, 2009:
Mark Jude Tramo, MD PhD, Harvard, MIT, & Mass Gen
Functional Brain Organization in Relation to Emotion
and Meaning in Music
When we experience the beauty of music…there is no
sound in our brains…. All acoustic information striking
our eardrums is transformed into neural information
represented by patterns of electrical activity – strings
if 0’s and 1’s whose bits vary depending on the pitch,
loudness, duration, consonance, and timbre of each
note, harmonic interval, and chord….
Retrieval from memory
 “inability to retrieve the word”
• As if the word were stored in some kind of
symbolic form in some memory location, from
which it has to be retrieved
 Better: inability to access the internal
representation of the word
Links for intermodal communication
 Examples:
• Phonological – grammatical – semantic
• Phonological recognition – phonological production
 I.e., Wernicke’s area and Broca’s area
 Two related problems:
• What information is transmitted?
• Over what kind of connection?
Transmitting information
 For example,
• from angular gyrus to Wernicke’s area
•
 Conceptual or lemma inf in AG
 Phonological inf in Wernicke’s a.
from Wernicke’s area to Broca’s area
 Some kind of phonological information
• Some kind of code?
• Phonemic transcription?
• Phonological image in Wernicke’s a.
• Phonological motor program in Broca’s a.
What kind of connection?
 Two possibilities
• The way its done in computers
•
 Vector coding, a bus
 Only a few fibers needed
 But: some means of coding is needed
Local coding, individual connections
 A very large number of fibers needed
 By comparison, grossly inefficient
Vector coding vs. Local coding
 Vector coding requires only a small bus
• A 32-bit bus can carry and of 232 items of
•
information
The way it’s done in personal computers
 Nowadays, many use a 64-bit bus
 Local coding requires a very large bus
• A separate fiber for each item
• For arcuate fasciculus, hundreds of thousands
 Anatomical evidence can provide answer
• How many fibers in arcuate fasciculus?
Anatomical evidence:
Wernicke’s area and Broca’s area
 Connected by arcuate fasciculus
 Auditory phonological images linked to
articulatory images
 Individual connections would require
many thousands of fibers
 How many fibers in arcuate fasciculus?
How many Fibers in Arcuate fasciculus?
 Selden (1985:300): “macroscopically most
obvious”
 Consists of axons of neurons distributed
throughout Wernicke’s area
 Therefore, millions of fibers
 Different fibers originate in different
locations throughout Wernicke’s area
How many fibers in arcuate fasciculus:
theoretical calculation
 From each minicolumn, at least one axon to
Broca’s area
 How many minicolumns in Wernicke’s area?
• 20 sq cm x 145,000 minicolumns per sq cm
• 2,900,000
 Therefore, at least 2,900,000 axons in
arcuate fasciculus
So what is the information that is sent?
 We have to avoid thinking of the brain as a
computer
 An axon sends only one kind of information:
• Activation
•
 Can come in different degrees
• i.e., different frequencies of firing
Nothing else needed, since it is a unique
connection
 This is a property of connectivity
• All the information is in the connectivity
• “Connectivity rules!”
end