Ling 411 – 20
More on the
Functional Neuroanatomy
of Language
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
Koby
Music
Mauvais
LH-RH anat.
Tsai
Tones
Shelton
Thalamus
Delgado
Amusia
Hickok’s proposal on conduction aphasia
 At least one type of conduction aphasia
results from damage to phonological
processing systems in auditory cortex
which participate both in speech
perception and in speech production
• i.e., Wernicke’s area
 The asymmetry between production
(impaired) and comprehension (spared) can
be explained in terms of different degrees
of lateralization in the … systems that
support (or can support) these functions
(2000: 89)
Why isn’t this Wernicke’s aphasia?
 The area identified by Hickok for
conduction aphasia is Wernicke’s area
• Hickok claims that such damage is responsible
for conduction aphasia
 Conduction aphasia and Wernicke’s aphasia
• In conduction aphasia
 Comprehension is relatively ok
• Hickok claims the RH pSTP also participates in
speech recognition
 Patient is aware of errors in repetition
• Hickok proposes that in Wernicke’s aphasia the
damage extends beyond Wernicke’s area
 MTG (p. 101), (maybe also AG?)
Hickok & Poeppel (2000)
 Left temporal-parietal-occipital junction
area is “typically involved to some extent
in Wernicke’s aphasia, which … has a
prominent post-phonemic component to
the deficit profile. (Toward a functional
neuroanatomy of speech perception, p. 7)
MR template – Wernicke Aphasia (patient I)
Poster
-ior
portio
n of
superior
and
middle
temporal
gyri
MR template – Wernicke Aphasia (patient II)
Superior
temporal
gyrus,
AG,
SMG
Hickok’s proposal on speech perception
 The primary substrate for speech perception
is the posterior temporal plane (pSTP)
•
pSTP – Heschl’s gyrus plus planum temporale
 Conduction aphasia can result from damage
to exactly this area in left hemisphere
 Apparent paradox:
• Comprehension is preserved in conduction aphasia
 Explanation:
• Speech perception is subserved by pSTP in both
hemispheres
(2000: 90)
RH involvement in speech perception
Isolated RH
 Evidence from tests of isolated RH
• Split-brain studies
• Wada test
•
•
 Sodium amytol, sodium barbitol
Discrimination of speech sounds
Comprehension of syntactically simple speech
(Hickok 2000: 92)
Benson and Ardila on conduction
aphasia
“… a single type of aphasia may have distinctly
different loci of pathology. Both conduction
aphasia and transcortical motor aphasia are
examples of this inconsistency.” (117)
(See also p. 135)
Hannah Damasio on conduction aphasia
“Conduction aphasia is associated with left perisylvian
lesions involving the primary auditory cortex…, a portion
of the surrounding association cortex…, and to a variable
degree the insula and its subcortical white matter as well
as the supramarginal gyrus (area 40). Not all of these
regions need to be damaged in order to produce this type
of aphasia. In some cases without involvement of auditory
and insular regions, the compromise of area 40 is
extensive…. In others, the supramarginal gyrus may be
completely spared and the damage limited to insula and
auditory cortices … or even to the insula alone….”
(1998: 47)
CT template – Conduction Aphasia (patient I)
CT template – Conduction Aphasia (patient II)
Left
auditory
cortex
and
insula
Kurt Goldstein on Conduction Aphasia
 Kurt Goldstein
(1878-1965)
•
•
•
German
Studied with Wernicke
Influenced by Gestalt psychology (Koffka 1935)
•
•
Became the best-known spokesman for this approach
Important publication in 1948
•
•
Not the arcuate fasciculus but a central area
Proposed the term ‘Central Aphasia’
 Adopted a “holistic” approach
 Criticized the Wernicke-Lichtheim view of
conduction aphasia
 Now we see that there are really three kinds of
conduction aphasia
3 or 4 types of conduction aphasia
 Damage to arcuate fasciculus
• The classical one
 Proposed by Wernicke and Lichtheim
 Doubted by Hickok
• But Hickok is wrong!
 Damage to SMG
• Proposed by Goldstein
• Supported by Hickok
 Damage to Wernicke’s area (but not to AG)
• New proposal of Hickok
 Possible 4th type: Damage to insula
Repetition in Wernicke’s aphasia
Model for Repetition
 black
Patient’s Response
 blackboard
 shoe
 shoelace
 He parks the car
 He park … he came with
the car. He came with
his car.
 It goes between two
others
 It went two cars …
between the cars
Goodglass on conduction aphasia
Unlike the patient with Wernicke’s aphasia, patients
with conduction aphasia are usually acutely aware of
the inaccuracy of their production and make repeated
attempts at self-correction. As they do so, they may
correct one portion of the target while introducing a
new error elsewhere, sometimes wandering further
afield and sometimes approaching closer to or even
succeeding in saying the desired word.
(1993: 142)
Picture naming in conduction aphasia
 Picture of..
 Patient’s Response

whistle
 tris.. chi.. trissle..
sissle.. twiss.. ciss.

pretzel
 trep.. tretzle..
trethle.. tredfl… ki
Lamb’s email query to Hickok
(April 1, 2010)
Hi Greg - In my neurolinguistics class we have just been
considering your 2000 paper from the Grodzinsky et al.
volume, with its new perspective on, among other things,
these two types of aphasia. Very intriguing, but I have a
question:
How do you explain this:
When you give a conduction aphasic words to repeat,
he/she commonly produces a phonemic paraphasia and
then keeps trying, since he/she recognizes the error; but
a Wernicke's aphasic usually stops after one incorrect
repetition, evidently unaware of the error.
Acc. to your proposal, both types of aphasic have LH
phonological recognition wiped out, and both have intact
RH pSTG.
Hickok’s response (April 1, 2010)
Hi Syd, Good to hear from you. That is an interesting
question. I think there are two possibilities. One is that
the conduction aphasics don't have as much damage to the
left hemisphere phonological systems we (I) might have
thought. I.e., the damage is more often involving the
posterior Sylvian region (Spt). The intact left and right
hemi phonological systems allow the patient to clearly
recognize their errors and self correct. Wernicke's on the
other hand typically have extensive damage to the left hemi
phonological systems which, because of their role
in production, may have a larger role in self monitoring.
Another possibility, perhaps in conjunction with the first, is
that wernicke's have damage to semantic (access) systems
as well. it may be much harder to notice a phonological
error if you can't tell whether it is a word or not.
The Connection between Phonological
Recognition and Phonological Production
Hickok (2000) proposes a revision of the
standard hypothesis
The revision is like that previously
proposed by Goldstein
Now, evidence from DTI (cf. Friederici)
REVIEW
The Perception-Production Interface
 We have phonological recognition in Wernicke’s
area
•
And in RH homolog of Wernicke’s area
•
And in RH homolog of Broca’s area
•
•
Direct connection: the arcuate fasciculus
Proposed by Wernicke, supported by Geschwind
•
•
Supramarginal gyrus (SMG) as intermediary
Proposed by Hickok
 with support from Damasio and Goldstein
 And phonological production in Broca’s area
 Clearly, they have to be connected
 The traditional view
 Alternative view
The Intermediate System Hypothesis
Auditory-Motor
Interface
Speech
Recognition
Speech
Production
Supramarginal
Gyrus
Arguments for Direct
Connection Hypothesis
 No additional intervening structure needed
 We have anatomical evidence for the
arcuate fasciculus
• And for its connections from Wernicke’s area
to Broca’s area
Arguments for SMG Interface Hypothesis
 Damasio cites SMG damage as a major cause of
conduction aphasia
•
Consistent with earlier findings of Goldstein
 “Central aphasia” (Goldstein 1948)
 Connectivity studies in non-human primates fail to
find direct connection between auditory cortex and
ventral posterior frontal lobe
•
But support the claim that the lower parietal lobe provides
an interface between these areas (Hickok 2000: 99)
 SMG is a likely site of higher-level proprioceptive
processing of speech
Arguments for SMG Interface Hypothesis
 Damasio cites SMG damage as a major cause of
conduction aphasia
•
Consistent with earlier findings of Goldstein
 “Central aphasia” (Goldstein 1948)
 Anatomical studies in macaque monkeys fail to find
direct connection (between corresponding areas)
(Hickok 2000: 99)
 SMG is a likely site of higher-level proprioceptive
processing of speech
•
(next slide)
Motor and Somatosensory Areas for speech
Central
Sulcus
1 – Phonological
production
Post-Central
Sulcus
Leg
Trunk
2 – Articulation
3 – Articulatory
monitoring
4 – Phonological
monitoring
Arm
Hand
Fingers
1
2Mouth3
4
Presumed interconnections of speech areas
Central
Sulcus
1 – Phonological
production
Post-Central
Sulcus
2 – Articulation
3 – Articulatory
monitoring
4 – Phonological
monitoring
5 – Primary
auditory
6 – Phonological
recognition
1
2 3
5
4
6
And there’s more than meets the eye
 The phonological recognition area includes
the temporal plane
 The phonological monitoring area includes
the parietal operculum
 Both large areas
REVIEW
The Sylvian Fissure
REVIEW
Evidence for left pSTP involvement
in speech production
 Erratic speech of Wernicke’s aphasics
 Conduction aphasia from damage to left pSTP
 Intraoperative stimulation of left pSTP
•
•
“distortion and repetition of words and syllables” (Penfield &
Roberts 1959)
N.B.: As in Wernicke’s aphasia
 MSI study shows activity in left pSTG just before
speech production (picture naming) (Levelt et al.
1998)
 fMRI study: similar results – no RH activity shown
(Hickok et al. 1999)
(Hickok 2000: 93-4)
An MSI study from Max Planck Institute
Diffusion Tensor Imaging (DTI)
 New and very informative technique
 Uses MRI
 Allows observation of molecular diffusion
in living tissues
 Makes use of
• Brownian movement
• Magnetic properties of hydrogen nuclei
 Two of them in every water molecule (H2O)
 Water moves along lines of least resistance
• i.e., along white matter axons
 aided by myelin
Uniformity of cortical strucure
across mammals?
 The hypothesis of uniformity
• Very important for perceptual neuroscience
• Allows data from experiments on cats and
monkeys to be applied to human cortical
structure and function
 Including higher levels – language
 But: this hypothesis applies to grey matter
• Not white matter
 Cortico-cortical connections
 DTI shows that white matter connections
differ across mammals
Arcuate fasciculus in different primates
Asif Ghazanfar, Nature Neuroscience 11:4.382-384, April 2008
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:
Brodmann areas in LH
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.
What?!!!
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)
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
end