Download lecture 35 - McLoon Lab - University of Minnesota

Cerebral Cortex 3
Language and brain
Hemispheric difference
Yasushi Nakagawa
Department of Neuroscience
University of Minnesota
1
Speech and Language
Vocal communication mediated by fully-developed speech and language
is a uniquely human trait.
Speech: mechanical aspects of verbal communication (articulation, voice, fluency)
Language: a higher- order function, based on accepted rules that govern what words mean, how to make new
words, how to put words together, and what word combinations are appropriate in specific situations
useful website to check: http://www.asha.org/public/speech/development/language_speech.htm
Speech and language disorders
expressive: problems in expressing speech or language
receptive: problems understanding speech or language
mixed: both comprehension and production are impaired
Speech disorders: lisp (articulation), stuttering (fluency), dyspraxia (generation and proper sequencing of speech
sounds), dysarthria (voice)
Language disorders: deficits in encoding or decoding information in phrases and sentences according to accepted
rules, such as those of grammar. Language disorders include specific language impairment (SLI) and dyslexia.
2
What is aphasia?
a disorder that results from damage to the parts of the
brain that contain language
-affects one million people in the U.S.
-caused by:
stroke (most common) 25-40% of patients with stroke survivors have aphasia
head trauma...about 1/3 of severe head injuries are accompanied by aphasia
brain tumors
infections
causes problems with any or all of the following:
speaking, listening, reading, and writing
Individuals with aphasia may also have other problems, such
as dysarthria, apraxia or swallowing problems.
A classical model of brain and language was developed in
the 19th century by neurologists studying patients with
aphasia.
3
Specific cortical regions are involved in
1
language processing
C H A P T E R
Pierre Paulof
Broca
(1824-1880)
Neurobiology
Language
-French
surgeon, neurologist,
1
2 neuroanatomist
ven L. Small
andhe
Gregory
Hickoka patient who had severe impairment of language. This patient
-In 1861,
came
across
sity of California, Irvine, CA, USA; 2Department of Cognitive Sciences, Center for
spoke
only “tan,
tan”,
although
heCA,
could
r for Cognitive
Neuroscience,
University
of California,
Irvine,
USA understand the language pretty well. After he
died, Broca did an autopsy and found a large lesion in the left frontal lobe.
RY
gical basis of human
us of attention in medibrain basis of language
Pierre Paul Broca in the
he patient Louis Victor
ented to the Hôpital
lty speaking, purport,” sometimes as a pair
by gestures (Domanski,
r until autopsy, when
hat some neurological
lection of serous fluid)
osterior inferior frontal
A subsequent patient,
f speech output (five
n not dissimilar to that
he ongoing debates at
of language, including
uage” to the frontal
aud, 1825; Gall &
oca to investigate this
FIGURE 1.1 The exterior surface of the brain of LeBorgne (“tan”).
-Broca saw
about(1874),
ten the
more
patients over
the next several years and found that everyone
Wernicke
diagram-making
of Lichtheim
(1885)symptoms
(Figure 1.2) and
Grashey
(1885),in
thethe
anatomy
with similar
had
a lesion
left offrontal lobe.
Déjerine (1895), and of course many other contributors.
In the past century, Norman Geschwind recapitulated
and added to the language “center” models that preceded him and presented a reconceptualized “connectionist” view of the brain mechanisms of language
4
Broca’s aphasia
-non-fluent, telegraphic, poorly articulated verbal output
-meaning is conveyed by content or information-carrying words such as nouns and verbs (nouns are
named more accurately than verbs)
-function words (e.g., articles, conjunctions, prepositions, auxiliary verbs, pronouns) are often omitted
(agrammatic speech production)
-An example of Broca’s aphasia:
http://www.youtube.com/watch?v=f2IiMEbMnPM
5
6
Broca’s area
3. THE VENTROLATERAL FRONTAL REGION
68
2 Vascularization of the Brain and Spinal Cord
a
5
6
b
4
4
3
3
7
8
2
5
6
7
2
6
7
1
5
4
8
1
9
3
11
2
10
12
Fig. 2.5 (a) Vascularization of the medial surface of the cerebral cortex by the anterior (ACA in light red) and posterior (PCA in red) cerebral arteries. The vascular territory of the middle cerebral artery (MCA)
is uncoloured. The ACA gives off the following branches: 1 orbitofrontal artery; 2 frontopolar artery; 3–5 anterior, middle and posterior frontal arteries; 6 paracentral artery; 7, 8 superior and inferior parietal
arteries. The PCA divides into: 1 hippocampal arteries (not shown);
2–4 anterior, middle and posterior temporal arteries; 5 calcarine artery;
6 parieto-occipital artery; 7 splenial artery (after ten Donkelaar et al.
2007). (b): Vascularization of the lateral surface of the cerebral cortex,
largely by the middle cerebral artery (MCA; uncoloured). The vascular
territories of the ACA and PCA are indicated in light red and red,
respectively. The MCA gives off the following branches: 1 orbitofrontal
artery; 2 prefrontal artery; 3 precentral artery; 4 central artery; 5, 6 anterior and posterior parietal arteries; 7 angular artery; 8 temporo-occipital
artery; 9–11 posterior, middle and anterior temporal arteries; 12 temporopolar artery (based on Nieuwenhuys et al. 1988; after ten Donkelaar
et al. 2007).
(3D). 3D-TOF is usually better for vessels with high flow
velocity such as the cervical arteries and the circle of Willis,
whereas 2D-TOF is more appropriate for assessing vertebral veins and sinuses. Phase-contrast MRA is based on
signals coming from phase shifts of protons in flowing
blood. With this technique, it is possible to combine imaging
with measurement of flow velocities and flow directions.
and extending to the superior frontal sulcus on the superior lateral surface; posteriorly, the arterial territory extends to the
parieto-occipital sulcus; and (2) callosal branches for the rostrum, genu, corpus and splenium of the corpus callosum. The
terminal pericallosal branches are joined posteriorly by the
splenial branches of the PCA. Cortical arteries of the M4 segment of the MCA extend over the lateral surface of the hemisphere, usually to the superior frontal sulcus, the intraparietal
sulcus and the inferior temporal gyrus. On the orbitofrontal
surface, the arterial territory of this artery includes the lateral
orbital gyri. Leptomeningeal branches of the PCA include the
hippocampal arteries, the splenial artery for the splenium of the
corpus callosum, and cortical branches to the inferomedial surfaces of the temporal and occipital lobes, extending to the parieto-occipital fissure (for hippocampal arteries, see Erdem et al.
1993; Duvernoy 1998; Huther et al. 1998). Perforating
branches of the cerebral arteries are the hypophysial arteries,
the anterior choroidal artery, the anterior communicating artery,
perforating branches from the anterior, middle and posterior
cerebral arteries, thalamoperforating and thalamogeniculate
branches from the PCA, and the posterior choroidal arteries
(see Sect. 2.6).
The variability of the territories of the major cerebral
arteries has extensively been studied by van der Zwan (1991)
and van der Zwan et al. (1992). van der Zwan simultaneously
injected the six major cerebral arteries (under the same pressure) with different-coloured Araldite F mixtures under standardized conditions to obtain the most realistic territorial
distribution. The variability of the territories of the major
cerebral arteries appeared to be much larger than generally is
described in the literature (Fig. 2.6):
territory of MCA
FIGURE 3.2
The sulcal and gyral morphology of the ventrolateral
frontal region in the human brain. The shaded region represents
the orbitofrontal cortex that is continuous with the pars orbitalis of the
inferior frontal gyrus. Abbreviations: aalf, anterior ascending ramus of
the lateral fissure (ascending sulcus, vertical sulcus); ascs, anterior
subcentral sulcus; cs, central sulcus; ds, diagonal sulcus; half, horizontal anterior ramus of the lateral fissure (horizontal sulcus); IFG,
inferior frontal gyrus; ifs, inferior frontal sulcus; iprs, inferior precentral sulcus; los-p, posterior ramus of the lateral orbital sulcus; MFG,
middle frontal gyrus; Op, pars opercularis of the inferior frontal
gyrus; Or, pars orbitalis of the inferior frontal gyrus; PrG, precentral
gyrus; prts, pretriangular sulcus; ScG, subcentral gyrus; STG, superior
temporal gyrus; sts, superior temporal sulcus; Tr, pars triangularis of
the inferior frontal gyrus; ts, triangular sulcus (incisura capitis).
-inferior part of the frontal lobe just rostral to the precentral gyrus (area 44 and 45)
-served by upper branches of the middle cerebral artery (MCA)
-Broca’s aphasia is the result of massive damage to the territory
ofSupply
the
divisions of MCA and
2.5
Arterial
of theupper
Cerebral Cortex
involves more than just the Broca’a area. As a result, some patients with Broca’s aphasia also have
motor weakness on the right
side (more severe for arms than for legs).
subdivisions of the inferior frontal region (Mohr, 1976;
et al., 1978). The syndrome
aphasia,
-Broca’s area is on the left Mohr
hemisphere
in 90%of Broca’s
of overall
population (70% of left-handed people)
which is characterized by severe impairment in lan-
GURE 3.1 Cytoarchitectonic map of the lateral surface of the
man and the macaque monkey frontal lobe by Petrides and Pandya
94). The white region on the precentral gyrus is the primary motor
tex (area 4) and the various subdivisions of the premotor region
ea 6). The inset shows the location of area 44 in the macaque monkey
the fundus of the inferior limb (ramus) of the arcuate sulcus.
ontal cortical region that plays a critical role in cerin aspects of language production (Friederici, 2011;
eschwind, 1970; Grodzinsky, 2000). Several attempts
guage production (including impaired syntactic processing), is the result of massive damage to the
territory of the upper division of the middle cerebral
artery and involves not only the cortical structures in
the posterior part of the inferior frontal gyrus (i.e.,
areas 44 and 45) but also the adjacent frontoparietal
opercular region and the anterior parts of the insula
(Ackermann & Riecker, 2004; Baldo, Wilkins, Ogar,
Willock, & Dronkers, 2011; Dronkers, 1996; Mohr,
1976). The best evidence thus far linking specific parts
of the inferior frontal gyrus to language production
has been obtained from electrical stimulation of the
cerebral cortex under local anesthesia during brain sur-
The arterial cerebral circulation can be divided into two systems: (1) the leptomeningeal arteries, consisting of the terminal
branches of the anterior, middle and posterior cerebral arteries
(for collateral circulation, see Vander Eecken 1959; Duvernoy
et al. 1981); and (2) the perforating branches that perforate the
brain parenchyma as direct penetrators. They arise from the circle of Willis, from its immediate branches and also from the
leptomeningeal arteries, and supply the basal ganglia, the internal capsule and the diencephalon. Leptomeningeal branches
of the three cerebral arteries and their territories are shown in
Fig. 2.5. The leptomeningeal anastomoses in the subarachnoid space between the arterial boundary zones represent connections between distal branches of major cerebral arteries
(Duvernoy et al. 1981). These arterial boundary zones, also
termed “watershed zones”, are especially susceptible to damage following any generalized decrease in blood flow as is the
case in severe systemic hypotension. The distal segment of the
ACA, the pericallosal artery, usually gives rise to: (1) cortical
branches to the medial surface of the hemisphere including the
medial orbital gyri on the orbitofrontal surface of the hemisphere
6
Wernicke’s aphasia
-first reported by Karl Wernicke (1848-1905)
-fluent, effortless, but relatively meaningless, spontaneous speech and repetition
-impaired comprehension at the word, sentence, and discourse levels
-Spoken language may be limited to jargon comprising either real words or neologisms (nonwords
such as “klimorata”) or a combination of the two.
-usually caused by neural dysfunction in regions supplied by the lower branches of the left MCA
-Wernicke’s area includes posterior, superior
part of the temporal lobe as well as inferior
part of the parietal lobe
Wernicke’s area
-An example of Wernicke’s aphasia:
http://www.youtube.com/watch?v=aVhYN7NTIKU&feature=relmfu
7
Specific cortical regions are involved in
language processing
-Wernicke proposed that complex cognitive functions result from interconnections
between several regions of the brain
Wernicke postulated that language involves separate
motor and sensory programs:
-sensory functions:
angular gyrus integrates visual and auditory
information, and spoken or written words are
transformed into neural code
in Wernicke’s area, it is recognized as language and
associated with meaning
-motor functions:
Broca’s area contains the rules or grammar for
transforming sensory information into a motor
representation
8
Conduction aphasia
Wernicke’s area and Broca’s area are connected by a robust fiber bundle named arcuate
fasciculus.
Wernicke found patients who show a type of aphasia different from Broca’s and
Wernicke’s aphasia.
Conduction aphasia
-intact understanding of written and spoken words
-no motor difficulty when they speak
-lack of coherency (omit parts of words or
substitute incorrect sounds)
Traditionally, conduction aphasia is thought to be
caused by a lesion in the arcuate fasciculus and thus
is considered a “disconnection syndrome”. However,
this hypothesis has been recently challenged.
9
Functional imaging of language areas
PET (positron emission tomography)
A. looking at words activates primary visual area and visual association area
B. listening the same words as used for A activates temporal cortex including Wernicke’s area
C. speaking words (repeating a word presented through either earphone or on a screen) activates
Broca’s area
D. subjects were asked to respond to the word “brain” with an appropriate verb (e.g., to think);
many areas are activated (frontal lobe, Broca’s, Wernicke’s)
10
Does Broca’s area contain grammatical
rules of language?
-in 1960s, linguist Noam Chomsky proposed that all natural languages share a common
design (universal grammar)
-is there a innate system in the human brain that evolved to mediate the grammatical
design of language?
-if so, where in the brain does such a system reside?
11
Does Broca’s area contain grammatical
rules of language?
-If a second language is learned early, both the native and the second languages are represented in a
common region in Broca’s area (A).
-If a second language is learned in adulthood, it is represented in a separate region in Broca’s area (B).
-Wernicke’s area does not show separation between languages.
-Learning an artificial languages (violating the rules of “universal grammar”) as a second language does
not increase the activity of Broca’s area.
-Broca’s area must contain some kind of constraints that determine the structure of all natural
languages.
12
Sign language
-Deaf people use ASL (American Sign Language) that uses hand gestures instead of
sound but has the same structural complexity as spoken languages.
-Signing is also localized to the left hemisphere.
-Damage to the left hemisphere can have specific consequences for signing just as for
spoken languages (right hemisphere damages rarely have consequences).
-damage to Wernicke’s area....comprehension is affected
-damage to Broca’s area...grammar and fluency are affected
-Emergence and operation of language capability in the left hemisphere does not need
functional auditory system.
13
Chimpanzee’s language areas?
-Chimps intentionally and referentially communicate via manual gestures and, like humans,
preferentially use their right hand for communicative gestures.
-They also use vocal signals to communicate with humans.
-Portions of the left inferior frontal gyrus (Broca’s area in humans) as well as other cortical
and subcortical regions in chimpanzees are active during the production of communicative
signals.
-Neurological substrates underlying language
production in the human brain may have been present
in the common ancestor of humans and chimpanzees.
-However, connection between Wernicke’s and Broca’s
area (dorsal pathway: arcuate fasciculus) was much less
robust in non-human primates.
766
15 The Cerebral Cortex and Complex Cerebral Functions
a
cs
ips
7b
22
6
b
cs
7a
sts
ips
8
40
22
44 6
45
45 44
c
47
37
sts
cs ips
39
46
40
8
39
10
44
45
47
22
6
sts
37
a: macaque
b: chimpanzee
c: human
14
New models of language and brain
14126 • J. Neurosci., October 10, 2012 • 32(41):14125–14131
Poeppel et al. • Towards a New Neurobiology of Language
Figure 1. A, The classical brain language model, ubiquitous but no longer viable. From Geschwind (1979). With permission of Scientific American. B, The dorsal and ventral stream model of
speech sound processing. From Hickok and Poeppel (2007). With permission from Nature Publishing Group.
Recent
advances of non-invasive functional neuroimaging
(fMRI, etc.) and other research
new maps of the functional anatomy of language. Speaking spasemantics,” and so on. From a neurobiological perspective, the goal
tially,have
local regions,
processing
hemispheres,
is tomodel.
develop mechanistic (and ultimately explanatory) linking hyfields
identified
a streams,
need the
totwo
revise
the and
classic
distributed global networks are now implicated in language funcpotheses that connect well defined linguistic primitives with equally
tion in unanticipated ways. For example, the canonical language
well defined neurobiological mechanisms. It is this next phase of
region, Broca’s
is now known, of
based
innovativeof
cytoneurolinguistic
research
that both
is now beginning,
developing
com-Broca’s
area area,
is composed
a on
number
subregions,
and
serve
language
and anonarchitectural and immunocytochemical data, to be composed of
putational neurobiology of language, and there are grounds for oplanguage
a numberfunctions.
of subregions (on the order of 10, ignoring possible
timism that genuine linking hypotheses between the neurosciences
laminar specializations), plausibly implicating a much greater
and the cognitive sciences are being crafted (Poeppel, 2012).
number of different functions than previously assumed (Amunts
Is the classical model salvageable? Are the new approaches and
-The
languages
are
into at leastinsights
twomerely
processing
(dorsal
et al.,
2010; Fig. 2), areas
supporting
bothorganized
language and non-language
expansionsstreams
and adaptations
to the and
traditional
processing. Moreover, there is emerging consensus that regions
view? We submit that the model is incorrect along too many
ventral)
are organized into at least two (and likely more) processing
dimensions for new research to be considered mere updates.
streams, dorsal and ventral streams (Hickok and Poeppel, 2004;
While these issues have been discussed in more detail, we point to
Saur et al., 2008), that underpin different processing subroutines,
just two serious shortcomings. First, due to its underspecification
for example, mediating aspects of lexical recognition and lexical
both biologically and linguistically, the classical model makes
15
Hemispheric differences
asymmetry in the human body
-mostly symmetric
-preferential use of a specific hand for skilled actions (most people use the right hand)
-hand preference can be observed already in the first week of life
-are hand preference and left hemisphere dominance of language associated?
-95% of right-handers are left-dominant for language
-70% of left-handers are also left-dominant for language
Broca: “we speak with the left hemisphere” (1865)
right-hand preference and left hemisphere dominance of language are
very clear
16
Laterality or asymmetry?
Jackson: complementary role for the right hemisphere in visuospatial functions (1874)
1960s: Roger Sperry’s hemisphere specialization theory
“indeed a conscious system in its own right, perceiving, thinking, remembering, reasoning, willing, and emoting, all at a
characteristically human level, and . . . both the left and the right hemisphere may be conscious simultaneously in different,
even in mutually conflicting, mental experiences that run along in parallel”
Hemispheric Differences
757
15.36 Lateralized
tions revealed by psychocal tests of commissurotomy
ents (after Sperry 1967)
-Although it is generally accepted that right
hemisphere is better equipped with visuo-spatial
information, this form of asymmetry is much less
clear.
Left visual field Right visual field
Image of right visual field
Image of left visual field
Left hemisphere
Right hemisphere
-Correlation between measures of laterality for
different functions are generally very low or nonsignificant.
Memory for shapes
Verbal memory
Left hand manipulation
and feeling shapes
Articulating speech
Right-hand skill
(writing, etc)
-Asymmetry is a better term than laterality.
Hearing speech
(right ear advantage)
Superior comprehension
of language
Hearing environmental sounds
(left ear advantage)
-Asymmetry is not even specific to humans.
Superior recognition of topological
forms, faces, etc. Body image
Right visual field
ding actions. For more abstract representations of objects
scenes, for instance for reasoning or problem solving,
metric information is not necessary (see also Jager and
Left visual field
from Sperry (1967)
indicating damage to the PPC, more in particular to the right
IPL. Later on reports were published on patients with typical left hemineglect and lesions in the region of the FEF, the
17
What is special about right hemisphere?
Comparison of stroke due to right and left MCA occlusion
-Both cause contralateral hemiparesis (motor weakness) and loss of sensory function.
-Left lesion can also involve severe language deficit.
-In right hemisphere lesion, patients are often unaware of their functional loss and pay no
attention to their disability (“anosognosia”).
-Anosognosia is often accompanied by left hemispatial neglect (caused by lesions in the
posterior parietal cortex).
-Similar lesions in the left hemisphere cause much less severe hemispatial neglect than the
right-side lesion.
-Prosopagnosia (problem in face recognition) is caused by bilateral lesion of the temporal
lobe, and functional imaging shows both hemispheres are active during face recognition.
-However, unilateral anterior temporal lesions have different patterns of impairment
depending on the side that is affected:
right lesion--loss of familiarity feeling, person-specific information retrieval
left lesion--impairment in name finding
18
y impaired.
be lesions,
e pattern of
s, there was
fic informaa prevalent
cognition is
s have been
e, the interselectively
sing
materials,
the aphasia
ugh someamusia was
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gnitive proPeretz and
o be a spey, suggestmay involve
so Chap. 7).
ence and as
ody is recpitch from
here capacsical stimual musician
n a normal
music is a
way matey. Expertise
rned to lisZatorre and
Anatomical, functional and genetic differences
between right and left hemispheres
759
a
Structural analysis
HG
HG
-size of gyri in temporal cortex: L>R
-similar in chimpanzee cortex
-size difference already found in 5 months-old fetuses
b
si
TG1
TG2
sh
TG
PT
PT
pm
pm
c
HG
Functional analysis
-Connectional asymmetry also found early in development
-DTI studies found that connections between Broca’s and
Wernicke’s areas are much more robust on the left side.
-People with symmetrical distribution had higher
performance in verbal memory tasks
HG
Gene expression analysis
L
R
Fig. 15.38 Anatomical differences between the left and right hemispheres. In (a), von Economo and Horn’s data on asymmetry of Heschl’s
gyrus (HG) are shown; in (b) Geschwind and Levitsky’s data; and in (c)
Galaburda’s data on asymmetry of the planum temporale. pm posterior
margin of planum temporale, PT planum temporale, sh sulcus of Heschl,
si sulcus intermedius, TG, TG1, TG2 transverse gyri of Heschl (a after
von Economo and Horn 1930, (b) after Geschwind and Levitsky 1968,
and (c) after Galaburda et al. 1978b)
-identified 27 genes whose levels of expression is already
different between right and left cortex of 14-weeks old
human fetuses
ences
right cered Levitsky
he areas of
). The left
he primary
mal brains,
asymmetry
and Horn
(1930). It appeared that the auditory association cortex is
larger in the left hemisphere of the human brain (Galaburda
et al. 1978a, b; for recent data see Dorsaint-Pierre et al.
2006; Toga and Thompson 2007). Comparative studies
between human and non-human primates showed that
chimpanzees, similarly to humans, show an asymmetry in
the planum temporale (Gannon et al. 1998; Hopkins et al.
1998). However, only humans have a robust asymmetry
-Intrinsic, genetic program early in development may
contribute to the later anatomical and functional differences
between right and left hemispheres.
19
Genetic factors contribute to susceptibility to
speech and language impairments
Speech disorders: lisp (articulation), stuttering (fluency), dyspraxia (generation and proper
sequencing of speech sounds), dysarthria (voice)
Language disorders: deficits in encoding or decoding information in phrases and sentences
according to accepted rules, such as those of grammar. Language disorders include specific
language impairment (SLI) and dyslexia.
Speech and language disorders are:
-heritable and show strong familial aggregation
-an increase in monozygotic twin concordance rates over that of dizygotic twins
➔Much of this aggregation can be attributed to genetic influences.
Researchers have recently begun to identify genetic factors that may play a role in the etiology
of speech and language disorders.
20
Methods for Identifying Contributory Genetic Variants
For some genetic disorders, it is possible to select candidate genes on the basis of their
function alone.
However, for speech and language disorders, in which the underlying biological mechanism is
unclear, the identification of susceptibility genes usually starts with an unbiased screening
approach.
This step allows the identification of a candidate region in the human genome and thus acts
to reduce the number of possible contributory genes to a manageable size prior to a more
in-depth investigation. These screening approaches usually take the form of genome-wide
linkage or association studies.
One investigates families with members affected by the disorder under study.
Linkage studies look for regions of the human genome in which there is a correlation
between the level of genetic identity and the level of phenotypic similarity for any given sib
pair.
.
21
KE family and verbal dyspraxia
Verbal dyspraxia: difficulties in the control of orofacial muscles leading to a deficit in the
production of fluent speech. http://www.youtube.com/watch?v=tYmm23EPXjU
In 1980’s, a large family was found to be affected by this disorder. In addition to their speech
problems, affected members of this family also had expressive and receptive language deficits
and, in some cases, written language problems and nonverbal cognitive impairment.
The pattern of inheritance indicated that they may be caused by a mutation in a single gene.
22
KE family and verbal dyspraxia
Genome-wide linkage analysis identified linkage to chromosome 7q (Fisher et al., 1998) and
fine mapping of the locus indeed identified a mutation in the FOXP2 gene.
The relevance of FOXP2 mutations to other cases of verbal dyspraxia was supported by the
identification of an unrelated child with a similar form of speech impairment who was found
to have a chromosome rearrangement that disrupted the FOXP2 gene
The FOXP2 gene encodes a DNA-binding protein from the FOX family. This protein acts as a
transcriptional repressor.
The identification of FOXP2 opened up a whole field of research encompassing a wide range
of disciplines including neuroimaging, animal models (primarily mouse and songbird),
molecular studies of gene function and expression, and population and evolutionary studies
23