The present study aimed to determine whether observation of upper limb actions selectively influe... more The present study aimed to determine whether observation of upper limb actions selectively influences speech production. We compared the effects on children with those on adults, hypothesizing that action observation is used by children for speech learning. Children and adults observed an actor either grasping a cherry or an apple, or bringing the same fruits to his mouth. They pronounced the syllable/ba/ at the end of the action. In a control experiment, children and adults executed the two bringing-to-the-mouth actions, still pronouncing/ba/. As previously found ([Euro. J. Neurosci., 17 (2003) 179]; [Euro. J. Neurosci., 19 (2004) 192]), the observed kinematics of the action, which were different according to the fruit size, influenced lip shaping kinematics and voice formants. In addition, the effect was selective for the action since the observations of actions such as grasping and bringing-to-the-mouth affected formant 1 and formant 2 in the voice spectra, respectively. The effects on speech were greater in the children than in the adults. By contrast, the effects on lip shaping did not differ between the two groups. Effects similar to those found for action observation were found for action execution in spite of a different arm kinematics between children and adults. The results of the present study are discussed according to the hypothesis that action observation induces in the viewer action recognition and activation of the successive mouth act (probably grasping-with-the-mouth when observing grasping-with-the-hand and chewing when observing bringing-to-the-mouth). This subsequently seems to affect characteristics peculiar to the emitted vowel. This mechanism might have been used by humans to transfer a primitive arm gesture communication system from the arm to the mouth and may be further used by children for speech learning.
There is growing evidence that words that are acquired early in life are processed faster and mor... more There is growing evidence that words that are acquired early in life are processed faster and more accurately than words acquired later, even by adults. As neuropsychological and neuroimaging studies have implicated different brain networks in the processing of action verbs and concrete nouns, the present study was aimed at contrasting reaction times to early and later-acquired action verbs and concrete nouns, in order to determine whether effects of word learning age express differently for the two types of words. Our results show that while word frequency affected both types of words in the same way, distinct learning age effects were observed for action verbs and concrete nouns. A further experiment specified that this difference was observed for verbs describing actions belonging to the human motor repertoire, but not for verbs denoting actions past this repertoire (e.g. to neigh). We interpret these data within a recently emerging framework according to which language processing is associated with sensory motor programs.
The present study aimed to determine whether observation of upper limb actions selectively influe... more The present study aimed to determine whether observation of upper limb actions selectively influences speech production. We compared the effects on children with those on adults, hypothesizing that action observation is used by children for speech learning. Children and adults observed an actor either grasping a cherry or an apple, or bringing the same fruits to his mouth. They pronounced the syllable/ba/ at the end of the action. In a control experiment, children and adults executed the two bringing-to-the-mouth actions, still pronouncing/ba/. As previously found ([Euro. J. Neurosci., 17 (2003) 179]; [Euro. J. Neurosci., 19 (2004) 192]), the observed kinematics of the action, which were different according to the fruit size, influenced lip shaping kinematics and voice formants. In addition, the effect was selective for the action since the observations of actions such as grasping and bringing-to-the-mouth affected formant 1 and formant 2 in the voice spectra, respectively. The effects on speech were greater in the children than in the adults. By contrast, the effects on lip shaping did not differ between the two groups. Effects similar to those found for action observation were found for action execution in spite of a different arm kinematics between children and adults. The results of the present study are discussed according to the hypothesis that action observation induces in the viewer action recognition and activation of the successive mouth act (probably grasping-with-the-mouth when observing grasping-with-the-hand and chewing when observing bringing-to-the-mouth). This subsequently seems to affect characteristics peculiar to the emitted vowel. This mechanism might have been used by humans to transfer a primitive arm gesture communication system from the arm to the mouth and may be further used by children for speech learning.
ABSTRACT Behind the complex phenomenon of the phylogenetic development of tool use and its potent... more ABSTRACT Behind the complex phenomenon of the phylogenetic development of tool use and its potential causal implication for higher forms of cognition, there are important 'lower level' aspects of cognition that highlight how tool use plays a causal role in shaping both spatial and bodily representations, and this is the focus of this chapter. First, it offers a definition of the word tool and in particular of what can be called tool use in our perspective, for operational purposes. Second, it considers the causal role that tool use plays in producing changes in space perception and body representation. Third, it discusses the challenges tool use presents for the sensorimotor system of the human and non-human primate brain.
Evidence that the motor and the linguistic systems share common syntactic representations would o... more Evidence that the motor and the linguistic systems share common syntactic representations would open new perspectives on language evolution. Here, crossing disciplinary boundaries, we explore potential parallels between the structure of simple actions and that of sentences. First, examining Typically Developing (TD) children displacing a bottle with or without knowledge of its weight prior to movement onset, we provide kinematic evidence that the subphases of this displacing action (reaching + moving the bottle) manifest a structure akin to linguistic embedded dependencies. Then, using the same motor task, we reveal that children suffering from specific language impairment (SLI), whose core deficit affects syntactic embedding and dependencies, manifest specific structural motor anomalies parallel to their linguistic deficits. In contrast to TD children, SLI children performed the displacing-action as if its subphases were juxtaposed rather than embedded. The specificity of SLI's structural motor deficit was confirmed by testing an additional control group: Fragile-X Syndrome patients, whose language capacity, though delayed, comparatively spares embedded dependencies, displayed slower but structurally normal motor performances. By identifying the presence of structural representations and dependency computations in the motor system and by showing their selective deficit in SLI patients, these findings point to a potential motor origin for language syntax.
Background: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Int... more Background: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as "non-specific Intellectual Disability". The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation. Methods: We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age-and IQ-matched Down syndrome patients served as control.
Recent evidence has shown that processing action-related language and motor action share common n... more Recent evidence has shown that processing action-related language and motor action share common neural representations to a point that the two processes can interfere when performed concurrently. To support the assumption that language-induced motor activity contributes to action word understanding, the present study aimed at ruling out that this activity results from mental imagery of the movements depicted by the words. For this purpose, we examined cross-talk between action word processing and an arm reaching movement, using words that were presented too fast to be consciously perceived (subliminally). Encephalogram (EEG) and movement kinematics were recorded. EEG recordings of the "Readiness Potential" ("RP", indicator of motor preparation) revealed that subliminal displays of action verbs during movement preparation reduced the RP and affected the subsequent reaching movement. The finding that motor processes were modulated by language processes despite the fact that words were not consciously perceived, suggests that cortical structures that serve the preparation and execution of motor actions are indeed part of the (action) language processing network.
Along the evolutionary history, humans have reached a high level of sophistication in the way the... more Along the evolutionary history, humans have reached a high level of sophistication in the way they interact with the environment. One important step in this process has been the introduction of tools, enabling humans to go beyond the boundaries of their physical possibilities. Here, we focus on some "low level" aspects of sensorimotor processing that highlight how tool-use plays a causal role in shaping body representations, an essential plastic feature for eYcient motor control during development and skilful tooluse in the adult life. We assess the evidence supporting the hypothesis that tools are incorporated in body representation for action, which is the body schema, by critically reviewing some previous Wndings and providing new data from ongoing work in our laboratory. In particular, we discuss several experiments that reveal the eVects of tool-use both on the kinematics of hand movements and the localization of somatosensory stimuli on the body surface, as well as the conditions that are necessary for these eVects to be manifested. We suggest that overall these Wndings speak in favour of genuine tool-use-dependent plasticity of the body representation for the control of action.
Kinematic analysis of lip and voice spectrum analysis were used to assess the influence of both e... more Kinematic analysis of lip and voice spectrum analysis were used to assess the influence of both execution and observation of arm-mouth-related actions on speech production. In experiments 1 and 2 participants brought either a cherry or an apple to their mouth and either pronounced the syllable BA (experiment 1) or emitted a nonspeech-related vocalization (experiment 2). In the other three experiments participants observed arm actions performed by the experimenter and pronounced the syllable BA. In experiment 3, they observed the action of bringing the cherry or apple to the mouth. In experiments 4 and 5, they observed a pantomime of the same action performed by the experimenter with his own arm (experiment 4) or with a nonbiological arm (experiment 5). The results showed that the formant 2 of the vowel 'a' increased when participants executed the bringing-to-the-mouth act with the apple or observed its execution or pantomime with the experimenter's arm (experiments 1, 3 and 4). In contrast, no modification in the vowel formants was found during a nonspeech-related vocalization (experiment 2) and during observation of an action with a nonbiological arm (experiment 5). Finally, the opening of the lips was larger when the participant brought the apple rather than the cherry to the mouth and pronounced BA (experiment 1). Taken together, the results of the present study suggest that the execution and observation of the bringing-to-the-mouth action activate a mouth articulation posture (probably due to the act of food manipulation with the mouth) which selectively influences speech production. They support the idea that the system involved in speech production shares and may derive from the neural substrate which is involved in the control of arm-mouth interactions and, in general, of arm actions.
There is growing evidence that words that are acquired early in life are processed faster and mor... more There is growing evidence that words that are acquired early in life are processed faster and more accurately than words acquired later, even by adults. As neuropsychological and neuroimaging studies have implicated different brain networks in the processing of action verbs and concrete nouns, the present study was aimed at contrasting reaction times to early and later-acquired action verbs and concrete nouns, in order to determine whether effects of word learning age express differently for the two types of words. Our results show that while word frequency affected both types of words in the same way, distinct learning age effects were observed for action verbs and concrete nouns. A further experiment specified that this difference was observed for verbs describing actions belonging to the human motor repertoire, but not for verbs denoting actions past this repertoire (e.g. to neigh). We interpret these data within a recently emerging framework according to which language processing is associated with sensory motor programs.
Broca&amp... more Broca's area has been considered, for over a century, as the brain centre responsible for speech production. Modern neuroimaging and neuropsychological evidence have suggested a wider functional role is played by this area. In addition to the evidence that it is involved in syntactical analysis, mathematical calculation and music processing, it has recently been shown that Broca's area may play some role in language comprehension and, more generally, in understanding actions of other individuals. As shown by functional magnetic resonance imaging, Broca's area is one of the cortical areas activated by hand/mouth action observation and it has been proposed that it may form a crucial node of a human mirror-neuron system. If, on the one hand, neuroimaging studies use a correlational approach which cannot offer a final proof for such claims, available neuropsychological data fail to offer a conclusive demonstration for two main reasons: (i) they use tasks taxing both language and action systems; and (ii) they rarely consider the possibility that Broca's aphasics may also be affected by some form of apraxia. We administered a novel action comprehension test--with almost no linguistic requirements--on selected frontal aphasic patients lacking apraxic symptoms. Patients, as well as matched controls, were shown short movies of human actions or of physical events. Their task consisted of ordering, in a temporal sequence, four pictures taken from each movie and randomly presented on the computer screen. Patient's performance showed a specific dissociation in their ability to re-order pictures of human actions (impaired) with respect to physical events (spared). Our study provides a demonstration that frontal aphasics, not affected by apraxia, are specifically impaired in their capability to correctly encode observed human actions.
The present study aimed to determine whether observation of upper limb actions selectively influe... more The present study aimed to determine whether observation of upper limb actions selectively influences speech production. We compared the effects on children with those on adults, hypothesizing that action observation is used by children for speech learning. Children and adults observed an actor either grasping a cherry or an apple, or bringing the same fruits to his mouth. They pronounced the syllable/ba/ at the end of the action. In a control experiment, children and adults executed the two bringing-to-the-mouth actions, still pronouncing/ba/. As previously found ([Euro. J. Neurosci., 17 (2003) 179]; [Euro. J. Neurosci., 19 (2004) 192]), the observed kinematics of the action, which were different according to the fruit size, influenced lip shaping kinematics and voice formants. In addition, the effect was selective for the action since the observations of actions such as grasping and bringing-to-the-mouth affected formant 1 and formant 2 in the voice spectra, respectively. The effects on speech were greater in the children than in the adults. By contrast, the effects on lip shaping did not differ between the two groups. Effects similar to those found for action observation were found for action execution in spite of a different arm kinematics between children and adults. The results of the present study are discussed according to the hypothesis that action observation induces in the viewer action recognition and activation of the successive mouth act (probably grasping-with-the-mouth when observing grasping-with-the-hand and chewing when observing bringing-to-the-mouth). This subsequently seems to affect characteristics peculiar to the emitted vowel. This mechanism might have been used by humans to transfer a primitive arm gesture communication system from the arm to the mouth and may be further used by children for speech learning.
There is growing evidence that words that are acquired early in life are processed faster and mor... more There is growing evidence that words that are acquired early in life are processed faster and more accurately than words acquired later, even by adults. As neuropsychological and neuroimaging studies have implicated different brain networks in the processing of action verbs and concrete nouns, the present study was aimed at contrasting reaction times to early and later-acquired action verbs and concrete nouns, in order to determine whether effects of word learning age express differently for the two types of words. Our results show that while word frequency affected both types of words in the same way, distinct learning age effects were observed for action verbs and concrete nouns. A further experiment specified that this difference was observed for verbs describing actions belonging to the human motor repertoire, but not for verbs denoting actions past this repertoire (e.g. to neigh). We interpret these data within a recently emerging framework according to which language processing is associated with sensory motor programs.
The present study aimed to determine whether observation of upper limb actions selectively influe... more The present study aimed to determine whether observation of upper limb actions selectively influences speech production. We compared the effects on children with those on adults, hypothesizing that action observation is used by children for speech learning. Children and adults observed an actor either grasping a cherry or an apple, or bringing the same fruits to his mouth. They pronounced the syllable/ba/ at the end of the action. In a control experiment, children and adults executed the two bringing-to-the-mouth actions, still pronouncing/ba/. As previously found ([Euro. J. Neurosci., 17 (2003) 179]; [Euro. J. Neurosci., 19 (2004) 192]), the observed kinematics of the action, which were different according to the fruit size, influenced lip shaping kinematics and voice formants. In addition, the effect was selective for the action since the observations of actions such as grasping and bringing-to-the-mouth affected formant 1 and formant 2 in the voice spectra, respectively. The effects on speech were greater in the children than in the adults. By contrast, the effects on lip shaping did not differ between the two groups. Effects similar to those found for action observation were found for action execution in spite of a different arm kinematics between children and adults. The results of the present study are discussed according to the hypothesis that action observation induces in the viewer action recognition and activation of the successive mouth act (probably grasping-with-the-mouth when observing grasping-with-the-hand and chewing when observing bringing-to-the-mouth). This subsequently seems to affect characteristics peculiar to the emitted vowel. This mechanism might have been used by humans to transfer a primitive arm gesture communication system from the arm to the mouth and may be further used by children for speech learning.
ABSTRACT Behind the complex phenomenon of the phylogenetic development of tool use and its potent... more ABSTRACT Behind the complex phenomenon of the phylogenetic development of tool use and its potential causal implication for higher forms of cognition, there are important 'lower level' aspects of cognition that highlight how tool use plays a causal role in shaping both spatial and bodily representations, and this is the focus of this chapter. First, it offers a definition of the word tool and in particular of what can be called tool use in our perspective, for operational purposes. Second, it considers the causal role that tool use plays in producing changes in space perception and body representation. Third, it discusses the challenges tool use presents for the sensorimotor system of the human and non-human primate brain.
Evidence that the motor and the linguistic systems share common syntactic representations would o... more Evidence that the motor and the linguistic systems share common syntactic representations would open new perspectives on language evolution. Here, crossing disciplinary boundaries, we explore potential parallels between the structure of simple actions and that of sentences. First, examining Typically Developing (TD) children displacing a bottle with or without knowledge of its weight prior to movement onset, we provide kinematic evidence that the subphases of this displacing action (reaching + moving the bottle) manifest a structure akin to linguistic embedded dependencies. Then, using the same motor task, we reveal that children suffering from specific language impairment (SLI), whose core deficit affects syntactic embedding and dependencies, manifest specific structural motor anomalies parallel to their linguistic deficits. In contrast to TD children, SLI children performed the displacing-action as if its subphases were juxtaposed rather than embedded. The specificity of SLI's structural motor deficit was confirmed by testing an additional control group: Fragile-X Syndrome patients, whose language capacity, though delayed, comparatively spares embedded dependencies, displayed slower but structurally normal motor performances. By identifying the presence of structural representations and dependency computations in the motor system and by showing their selective deficit in SLI patients, these findings point to a potential motor origin for language syntax.
Background: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Int... more Background: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as "non-specific Intellectual Disability". The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation. Methods: We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age-and IQ-matched Down syndrome patients served as control.
Recent evidence has shown that processing action-related language and motor action share common n... more Recent evidence has shown that processing action-related language and motor action share common neural representations to a point that the two processes can interfere when performed concurrently. To support the assumption that language-induced motor activity contributes to action word understanding, the present study aimed at ruling out that this activity results from mental imagery of the movements depicted by the words. For this purpose, we examined cross-talk between action word processing and an arm reaching movement, using words that were presented too fast to be consciously perceived (subliminally). Encephalogram (EEG) and movement kinematics were recorded. EEG recordings of the "Readiness Potential" ("RP", indicator of motor preparation) revealed that subliminal displays of action verbs during movement preparation reduced the RP and affected the subsequent reaching movement. The finding that motor processes were modulated by language processes despite the fact that words were not consciously perceived, suggests that cortical structures that serve the preparation and execution of motor actions are indeed part of the (action) language processing network.
Along the evolutionary history, humans have reached a high level of sophistication in the way the... more Along the evolutionary history, humans have reached a high level of sophistication in the way they interact with the environment. One important step in this process has been the introduction of tools, enabling humans to go beyond the boundaries of their physical possibilities. Here, we focus on some "low level" aspects of sensorimotor processing that highlight how tool-use plays a causal role in shaping body representations, an essential plastic feature for eYcient motor control during development and skilful tooluse in the adult life. We assess the evidence supporting the hypothesis that tools are incorporated in body representation for action, which is the body schema, by critically reviewing some previous Wndings and providing new data from ongoing work in our laboratory. In particular, we discuss several experiments that reveal the eVects of tool-use both on the kinematics of hand movements and the localization of somatosensory stimuli on the body surface, as well as the conditions that are necessary for these eVects to be manifested. We suggest that overall these Wndings speak in favour of genuine tool-use-dependent plasticity of the body representation for the control of action.
Kinematic analysis of lip and voice spectrum analysis were used to assess the influence of both e... more Kinematic analysis of lip and voice spectrum analysis were used to assess the influence of both execution and observation of arm-mouth-related actions on speech production. In experiments 1 and 2 participants brought either a cherry or an apple to their mouth and either pronounced the syllable BA (experiment 1) or emitted a nonspeech-related vocalization (experiment 2). In the other three experiments participants observed arm actions performed by the experimenter and pronounced the syllable BA. In experiment 3, they observed the action of bringing the cherry or apple to the mouth. In experiments 4 and 5, they observed a pantomime of the same action performed by the experimenter with his own arm (experiment 4) or with a nonbiological arm (experiment 5). The results showed that the formant 2 of the vowel 'a' increased when participants executed the bringing-to-the-mouth act with the apple or observed its execution or pantomime with the experimenter's arm (experiments 1, 3 and 4). In contrast, no modification in the vowel formants was found during a nonspeech-related vocalization (experiment 2) and during observation of an action with a nonbiological arm (experiment 5). Finally, the opening of the lips was larger when the participant brought the apple rather than the cherry to the mouth and pronounced BA (experiment 1). Taken together, the results of the present study suggest that the execution and observation of the bringing-to-the-mouth action activate a mouth articulation posture (probably due to the act of food manipulation with the mouth) which selectively influences speech production. They support the idea that the system involved in speech production shares and may derive from the neural substrate which is involved in the control of arm-mouth interactions and, in general, of arm actions.
There is growing evidence that words that are acquired early in life are processed faster and mor... more There is growing evidence that words that are acquired early in life are processed faster and more accurately than words acquired later, even by adults. As neuropsychological and neuroimaging studies have implicated different brain networks in the processing of action verbs and concrete nouns, the present study was aimed at contrasting reaction times to early and later-acquired action verbs and concrete nouns, in order to determine whether effects of word learning age express differently for the two types of words. Our results show that while word frequency affected both types of words in the same way, distinct learning age effects were observed for action verbs and concrete nouns. A further experiment specified that this difference was observed for verbs describing actions belonging to the human motor repertoire, but not for verbs denoting actions past this repertoire (e.g. to neigh). We interpret these data within a recently emerging framework according to which language processing is associated with sensory motor programs.
Broca&amp... more Broca's area has been considered, for over a century, as the brain centre responsible for speech production. Modern neuroimaging and neuropsychological evidence have suggested a wider functional role is played by this area. In addition to the evidence that it is involved in syntactical analysis, mathematical calculation and music processing, it has recently been shown that Broca's area may play some role in language comprehension and, more generally, in understanding actions of other individuals. As shown by functional magnetic resonance imaging, Broca's area is one of the cortical areas activated by hand/mouth action observation and it has been proposed that it may form a crucial node of a human mirror-neuron system. If, on the one hand, neuroimaging studies use a correlational approach which cannot offer a final proof for such claims, available neuropsychological data fail to offer a conclusive demonstration for two main reasons: (i) they use tasks taxing both language and action systems; and (ii) they rarely consider the possibility that Broca's aphasics may also be affected by some form of apraxia. We administered a novel action comprehension test--with almost no linguistic requirements--on selected frontal aphasic patients lacking apraxic symptoms. Patients, as well as matched controls, were shown short movies of human actions or of physical events. Their task consisted of ordering, in a temporal sequence, four pictures taken from each movie and randomly presented on the computer screen. Patient's performance showed a specific dissociation in their ability to re-order pictures of human actions (impaired) with respect to physical events (spared). Our study provides a demonstration that frontal aphasics, not affected by apraxia, are specifically impaired in their capability to correctly encode observed human actions.
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