Intransitive Gestures Research Articles

What's Special about Human Imitation? A Comparison with Enculturated Apes.

What, if anything, is special about human imitation? An evaluation of enculturated apes’ imitation skills, a “best case scenario” of non-human apes’ imitation performance, reveals important similarities and differences between this special population of apes and human children. Candidates for shared imitation mechanisms include the ability to imitate various familiar transitive responses and object–object actions that involve familiar tools. Candidates for uniquely derived imitation mechanisms include: imitating novel transitive actions and novel tool-using responses as well as imitating opaque or intransitive gestures, regardless of familiarity. While the evidence demonstrates that enculturated apes outperform non-enculturated apes and perform more like human children, all apes, regardless of rearing history, generally excel at imitating familiar, over-rehearsed responses and are poor, relative to human children, at imitating novel, opaque or intransitive responses. Given the similarities between the sensory and motor systems of preschool age human children and non-human apes, it is unlikely that differences in sensory input and/or motor-output alone explain the observed discontinuities in imitation performance. The special rearing history of enculturated apes—including imitation-specific training—further diminishes arguments suggesting that differences are experience-dependent. Here, it is argued that such differences are best explained by distinct, specialized mechanisms that have evolved for copying rules and responses in particular content domains. Uniquely derived social and imitation learning mechanisms may represent adaptations for learning novel communicative gestures and complex tool-use. Given our species’ dependence on both language and tools, mechanisms that accelerated learning in these domains are likely to have faced intense selective pressures, starting with the earliest of human ancestors.

Brain Activity (fNIRS) in Control State Differs from the Execution and Observation of Object-Related and Object-Unrelated Actions

ABSTRACTThe authors explored cortical correlates of action execution and observation, directly comparing control condition condition and execution–observation, using functional near-infrared spectroscopy. Transitive actions (meaningful gestures produced in presence of an object) or intransitive actions (meaningful gestures produced in absence of an object) were performed. Increased oxygenated hemoglobin levels were revealed for both action execution and action observation in premotor cortex, and sensorimotor cortex compared to control condition. However, a higher activity in motor areas was observed for action execution than motor observation. In contrast the posterior parietal cortex was similarly activated in case of both execution and observation task. Finally, it was shown that action execution and observation of transitive more than intransitive gestures was supported by similar parietal posterior areas. These findings support the hypothesis of a partial common network for observation and execution of action, and significant implications related to action types (transitive vs. intransitive).

FNIRS measure of transitive and intransitive gesture execution, observation and imagination in ecological setting: A pilot study.

To explore the presence of differential cortical hemodynamic activations related to cognitive components of actions, we performed a fNIRS (functional Near-Infrared Spectroscopy) study during Observation (O), Execution (E) and Imagination (I) of complex and meaningful (transitive and intransitive) gestures in ecological setting. A pilot sample of 5 healthy adults underwent an event-related study consisting of these 3 different conditions, with O set as first and followed by a randomized presentation of E or I. fNIRS measurements were performed using a 24 channel array of optodes (8 light injectors and 8 detectors) placed over the contralateral central, centro-parietal, parietal and temporal areas. Results showed that the premotor (PMC) and the sensory-motor cortices (SM1) were recruited selectively during E, with levels of oxygenated hemoglobin (oxy-Hb) higher than the other conditions, while the posterior parietal cortex (PPC) showed increased oxy-Hb levels for both E and O. These data suggest that variations in hemodynamic responses can be attributed to different neural processes underpinning these tasks, with PMC and SM1 being more involved in action preparation and performance, and PPC prevalently dedicated to attentive processes related to the execution and observation of limb movements.

Transitive and intransitive gesture execution and observation compared to resting state: the hemodynamic measures (fNIRS).

The present study explored cortical correlates of gesture execution and observation in peripersonal space, using functional near-infrared spectroscopy (fNIRS). Moreover, a direct comparison was realized between resting state condition and execution/observation. Meaningful gestures produced in the presence (transitive action) or in the absence (intransitive action) of the object were considered in a real context (situated representation of gestures). Subjects were required to execute or observe transitive versus intransitive gestures during fNIRS registration. Gesture execution was related to higher brain activity (increased oxygenated hemoglobin levels) with respect to observation in motor areas (premotor cortex, PMC; supplementary motor cortex, SM1). In contrast, the posterior parietal cortex was similarly activated in case of both execution and observation task. Moreover, both tasks showed increased brain activity within these areas compared to resting state. Finally, it was shown that action execution and observation of transitive gestures was supported by similar parietal posterior areas. These findings support the hypothesis of a partial common network for observation and execution of gestures within peripersonal space, mainly in transitive condition.

V9. Distinct contributions of dorsal and ventral streams to imitation of transitive and intransitive gestures: Evidence from acute stroke patients

Background Meaningful gestures are one of the key features of social interaction and comprise both object-associated transitive movements (e.g. hammering) as well as intransitive movements referring to a communicative content (e.g. waving goodbye). The ability to imitate meaningful gestures is frequently impaired in apraxia due to left-hemispheric stroke. However, the pathophysiology behind these deficits so far remained unresolved. A dual stream-model for a dichotomized organisation of higher cognitive functions such as language or praxis has been proposed, with a dorsal stream involved in sensorimotor processing and a ventral stream for content and imagery. Aim of the study was to elucidate the role of the dual stream-model in imitation of meaningful movements using voxel-based lesion-symptom mapping (VLSM). Methods We performed VLSM in a sample of 136 left-hemispheric stroke patients (mean age ± SD 65 years ± 15, 83 male). Neuropsychological testing and MR-imaging were carried out in the acute phase after ischemic stroke (5.1 ± 1.9 days after symptom onset) to avoid interference with brain reorganization. Imitation deficits were assessed with a block of ten object-related movements and a block of ten communicative gestures presented by the examiner, patients were instructed to imitate the movement. Lesions were mapped on the diffusion-weighted image (if not available on Flair- image), statistical analysis with Brunner–Munzel Test was performed using non-parametric statistics implemented in MRIcron. Results Deficits in both, imitation of transitive and intransitive movements were associated with lesions in areas of the dorsal stream involved in motor control and action representations, such as the inferior parietal lobule, and the supramarginal gyrus. In addition to these common areas, deficits in imitation of intransitive movements showed a specific association with the superior and middle temporal lobe, whereas deficient transitive movements were also related to lesions within the ventral premotor cortex without involvement of temporal structures. Conclusion Deficits affecting imitation of transitive and intransitive gestures result from different and characteristic neuroanatomical lesion patterns. Our data suggest that imitation of transitive gestures depicting common tool-associated actions mainly involves stored motor programs and, thus, is mainly based on the dorsal stream. Conversely, imitation of intransitive communicative gestures additionally relies on the ventral stream, probably due to the higher semantic content, given the often symbolic character of intransitive gestures.

P169. Impaired gesture performance as potential endophenotype of schizophrenia

Introduction Disturbed social functioning including nonverbal communication is a core characteristic of schizophrenia. One crucial factor of nonverbal communication is gesturing. Gesturing is impaired in patients with schizophrenia. We aimed to test whether impairments in gesture performance would be present in unaffected first degree relatives of schizophrenia patients and could therefore be a potential marker of the disorder. Method We investigated 29 unaffected first degree relatives of schizophrenia patients and 29 control subjects matched for age, gender, education level, nonverbal intelligence and income. Participants performed a comprehensive test for gesture performance the Test of Upper Limb Apraxia (TULIA) ( Vanbellingen et al., 2010 ). In brief, the TULIA assesses the performance of gestures in two principal domains, i.e. imitation (production after demonstration) and pantomime (production following verbal instruction). For both domains three semantic subgroups were tested: meaningless, transitive (tool related) and intransitive (symbolic non-tool related) gestures. In addition motor behavior, working memory and frontal lobe function was assessed. Furthermore psychic experience was assessed in first degree relatives. Results First degree relatives of schizophrenia patients showed relatively severe difficulties during gesture performance. In fact, 24% of the relatives scored below the cut-off scores. In addition motor behavior was impaired in relatives. Relatives showed abnormal involuntary movements (AIMS), neurological soft signs (NSS) and abnormalities in movement (Modified Rogers Scale, MRS) as more prevalent. Moreover gesturing was predicted by impaired motor behavior in relatives. Conclusions Gesture performance impairment has been shown in unaffected first degree relatives of schizophrenia patients. Furthermore poor gesturing was associated with impaired motor behavior in first degree relatives. Our results indicate that deficits of gesturing could be linked to motor functioning. Moreover gesturing could present a potential maker of vulnerability for schizophrenia ( Table 1 ).

Insights into the neural mechanisms underlying hand praxis: implications for the neurocognitive rehabilitation of apraxia.

Insights into the neural mechanisms underlying hand praxis: implications for the neurocognitive rehabilitation of apraxia.

Short apraxia screening test

Background: Limb apraxia comprises many different and common disorders, which are largely unrecognized essentially because there is no easy-to-use screening test sensitive enough to identify all types of limb praxis deficits. Method: We evaluated 70 right-handed patients with limb apraxia due to a single focal lesion of the left hemisphere and 40 normal controls, using a new apraxia screening test. The test covered 12 items including: intransitive gestures, transitive gestures elicited under verbal, visual, and tactile modalities, imitation of meaningful and meaningless postures and movements, and a multiple object test. Results: Interrater reliability was maximum for a cutoff of >2 positive items identifying apraxia on the short battery (Cohen’s kappa .918, p < .0001), and somewhat less for >3 items (Cohen’s kappa .768, p < .0001). Although both results were statistically significant, >2 was higher, indicating greater apraxia diagnosis agreement between raters at this cutoff value. Conclusions: The screening test proved to have high specificity and sensitivity to diagnose every type of upper limb praxis deficit, thus showing advantages over previously published tests.

Temporal dynamics of action perception: Differences on ERP evoked by object-related and non-object-related actions

While neuropsychological dissociations suggest that distinct processes are involved in execution or perception of transitive (object-related) and intransitive (non-object-related) actions, the few neuroimaging studies that directly contrasted the brain activations underlying transitive and intransitive gesture perception failed to find substantial differences between the two action types. However, the distinction could be visible on brain activity timing within the fronto-parietal network. In this study, we used Event-Related Potential (ERP) method to assess the temporal dynamics of object-related and non-object-related action processing. Although both meaningful, only object-related actions involve object motor features. Accordingly, perception of the two action types would show distinct neural correlates. Participants were presented with four movie types (ORA, Object-Related Action, NORA: Non-Object-Related Action and 2 control movies) and were instructed to perform tasks that required explicit or implicit action recognition (specific action recognition or color change detection). Movies were presented as Point-Light Display (PLD) and thus provided only information about gesture kinematics regardless of action type. ERP were computed during movie visual perception and analyzed as a function of movie type and task. The main result revealed a difference between ORA and NORA on the amplitude of the P3a component in the fronto-parietal region. The difference observed around 250ms after movie onset do not likely origin from variation in low-level visual features or attention resource allocation. Instead, we suggest that it reflects incidental recruitment of object attributes during object-related action perception. The exact nature of these attributes is discussed.

The effects of visual half-field priming on the categorization of familiar intransitive gestures, tool use pantomimes, and meaningless hand movements.

Although the control of meaningful gestures is one of the most left-lateralized functions, the relative contribution of the two hemispheres to their processing is still debated. We tested the effects of primes appearing in the left or right visual field in the form of pictures (Experiment 1), and words (Experiment 2) on categorization of movies showing intransitive (“communicative”) gestures, tool use (transitive) pantomimes, and meaningless movements. Fifteen participants (eight women) watched 36 movies (12 from each category) primed for 150 ms with either a congruent or incongruent stimulus followed by a 50-ms mask. On congruent trials, a picture or word was directly related to the presented gesture, including nonsense pictures or non-words for meaningless actions. On incongruent trials, a picture or word belonged to a different category. In Experiment 1, intransitive gestures were categorized significantly faster than the other two types of hand movements. Moreover, whereas the categorization of transitive gestures was significantly facilitated by congruent pictures on the right, the effect was weaker for intransitive, and reversed for meaningless movements. In Experiment 2, intransitive gestures were again categorized significantly faster, but transitive significantly slower than the other two gesture categories. Yet, there was now a significant facilitation of intransitive, and inhibition of transitive gesture categorization following congruent prime words in the right visual field, and significantly faster categorization of intransitive gestures following incongruent words in the left visual field. These outcomes lend support to the complexity account of differences in left-hemisphere representations of meaningful gestures reported in the neuropsychological, behavioral, and neuroimaging literature. Nevertheless, they also indicate that the representations of intransitive gestures show some differential, and sometimes counterintuitive sensitivity to right hemisphere processing.

Representations of Transitive and Intransitive Gestures: Perception and Imitation

Representations of Transitive and Intransitive Gestures: Perception and Imitation

Does a lesion in Broca's area cause apraxia?

AbstractBackground and AimBroca's area, which comprises the inferior frontal gyrus and its surrounding regions, is associated with language function. Recent functional imaging studies showed that it is also related to processing goal‐directed actions.This study aimed to determine the types of action disorders that occur after damage to Broca's area.MethodsHere, we report four patients with left inferior frontal lesions that included Broca's area. The patients did not exhibit severe language comprehension impairment or paralysis that affected the apraxia testing. The patients were asked to perform intransitive gestures in response to verbal commands, imitate intransitive gestures, perform transitive gestures in response to verbal commands, perform transitive gestures in response to visual objects, imitate transitive gestures, and use tools.ResultsAll patients exhibited impaired gestures in response to verbal commands, while the performances regarding imitation and actual tool use were better. An error pattern analysis showed that the patients predominantly made spatial action errors. This pattern corresponds to the classical definitions of ideomotor apraxia.ConclusionThese results indicate that Broca's area mediates action production and that a lesion in this area can cause ideomotor apraxia. Although we should be cautious about the influence of aphasia, we believe that the comprehension deficit observed in our patients cannot account for their apraxic syndromes. Because the deficit was seen mainly for verbal commands, damage in Broca's area may have disrupted the association between verbal and action domains.

Familiarity modulates mirror neuron and mentalizing regions during intention understanding

Recent research suggests that the inference of others' intentions from their observed actions is supported by two neural systems that perform complementary roles. The human putative mirror neuron system (pMNS) is thought to support automatic motor simulations of observed actions, with increased activity for previously experienced actions, whereas the mentalizing system provides reflective, non-intuitive reasoning of others' perspectives, particularly in the absence of prior experience. In the current fMRI study, we show how motor familiarity with an action and perceptual familiarity with the race of an actor uniquely modulate these two systems. Chinese participants were asked to infer the intentions of actors performing symbolic gestures, an important form of non-verbal communication that has been shown to activate both mentalizing and mirror neuron regions. Stimuli were manipulated along two dimensions: (1) actor's race (Caucasian vs. Chinese actors) and (2) participants' level of experience with the gestures (familiar or unfamiliar). We found that observing all gestures compared to observing still images was associated with increased activity in key regions of both the pMNS and mentalizing systems. In addition, observations of one's same race generated greater activity in the posterior pMNS-related regions and the insula than observations of a different race. Surprisingly, however, familiar gestures more strongly activated regions associated with mentalizing, while unfamiliar gestures more strongly activated the posterior region of the pMNS, a finding that is contrary to prior literature and demonstrates the powerful modulatory effects of both motor and perceptual familiarity on pMNS and mentalizing regions when asked to infer the intentions of intransitive gestures.

Limb apraxia in corticobasal syndrome

Corticobasal syndrome (CBS) is a progressive neurodegenerative disorder with asymmetric presentation and course characterized by degeneration of basal ganglia and cortical structures. Limb apraxia is a commonly observed deficit in CBS. Few studies have examined comprehensively the nature of deficits in limb apraxia. The goal of our study was to investigate the severity of deficits in various conceptual and gesture production task modalities. CBS patients were divided in two groups based on the side of brain that was initially affected by the disease. Ten patients with right hemisphere presentation (RHP) and seven with left hemisphere presentation (LHP) were included. The results showed that while selective conceptual tasks deficits were present in both groups, the overall picture suggests preserved conceptual representations of tools and actions in CBS patients with either LHP or RHP. Both groups were impaired relative to controls on gesture production tasks. Performance on transitive gestures was more severely affected in both groups than intransitive gestures. Imitation was more severely affected than pantomime, suggesting deficits in visuomotor transformations. The addition of verbal cuing during concurrent imitation affected only the LHP patients, rendering them more impaired relative to controls in their imitation with verbal cuing as opposed to their imitation only performance. Imitation of non-representational gestures was least accurate and intransitive gestures were most accurate. Patients were more severely impaired relative to controls when holding the object and when they were shown pictures of tools to pantomime.

Exploring the Relationship Between Gestural Recognition and Imitation: Evidence of Dyspraxia in Autism Spectrum Disorders

In this study, the relationship between gesture recognition and imitation was explored. Nineteen individuals with Autism Spectrum Disorder (ASD) were compared to a control group of 23 typically developing children on their ability to imitate and recognize three gesture types (transitive, intransitive, and pantomimes). The ASD group performed more poorly than controls on all tasks of recognition and imitation. Higher performance on tests of working memory was associated with increased odds of successful imitation in both groups. Group differences remained even when working memory was statistically controlled for. An association was revealed in the ASD group between pantomime recognition and imitation but a similar association was not identified for intransitive gestures suggesting that recognition alone is not sufficient for imitation success.

Associations and dissociations of transitive and intransitive gestures in left and right hemisphere stroke patients

The study investigated performance on pantomime and imitation of transitive and intransitive gestures in 80 stroke patients, 42 with left (LHD) and 38 with right (RHD) hemisphere damage. Patients were also categorized in two groups based on the time that has elapsed between their stroke and the apraxia assessment: acute–subacute ( n = 42) and chronic ( n = 38). In addition, patterns of performance in apraxia were examined. We expected that acute–subacute patients would be more impaired than chronic patients and that LHD patients would be more impaired than RHD patients, relative to controls. The hemisphere prediction was confirmed, replicating previous findings. The frequency of apraxia was also higher in all LHD time post-stroke groups. The most common impairment after LHD was impairment in both pantomime and imitation in both transitive and intransitive gestures. Selective deficits in imitation were more frequent after RHD for transitive gestures but for intransitive gestures they were more frequent after LHD. Patients were more impaired on imitation than pantomime, relative to controls. In addition, after looking at both gesture types concurrently, we have described cases of patients who suffered deficits in pantomime of intransitive gestures with preserved performance on transitive gestures. Such cases show that the right hemisphere may be in some cases critical for the successful pantomime of intransitive gestures and the neural networks subserving them may be distinct. Chronic patients were also less impaired than acute–subacute patients, even though the difference did not reach significance. A longitudinal study is needed to examine the recovery patterns in both LHD and RHD patients.

Age-related changes in arm–hand postural knowledge

Cognitive changes have been reported during healthy ageing, but there have been no investigations of older people's knowledge of transitive and intransitive forelimb postures and movements. A total of 18 healthy elderly participants in two age groups, old (66–76 years) and older (77–88 years), all of whom performed normally on the Mini-Mental Status Examination (MMSE) and Boston Naming Test (BNT), performed a transitive and intransitive gesture postural discrimination test. Whereas there were no significant differences between the two groups in education or performance on the MMSE and BNT, the older group performed significantly worse on both transitive and intransitive posture recognition with more errors in the recognition of transitive than in the recognition of intransitive postures. However, the recognition of both transitive and intransitive declined with age at a similar rate. These results support the hypothesis that, with ageing, there is a decrement in the brain systems important in the recognition of transitive and intransitive posture.

A Common Network in the Left Cerebral Hemisphere Represents Planning of Tool Use Pantomimes and Familiar Intransitive Gestures at the Hand-Independent Level

Evidence from neuropsychology and neuroimaging implicates parietal and frontal areas of the left cerebral hemisphere in the representation of skills involving the use of tools and other artifacts. On the basis of neuropsychological data, it has been claimed that 1) independent mechanisms within the left hemisphere may support the representation of these skills (transitive actions) versus meaningful gestures that do not involve manipulating objects (intransitive actions), and 2) both cerebral hemispheres may participate in the representation of intransitive gestures. Functional magnetic resonance imaging was used to test these hypotheses in 12 healthy adults while they planned and executed tool use pantomimes or intransitive gestures with their dominant right (Exp. 1) or nondominant left (Exp. 2) hands. Even when linguistic processing demands were controlled, planning either type of action was associated with asymmetrical increases in the same regions of left parietal (the intraparietal sulcus, supramarginal gyrus, and caudal superior parietal lobule) and dorsal premotor cortices. Effects were greater for tool use pantomimes, but only when the right hand was involved. Neither group nor individual analyses revealed evidence for greater bilateral activity during intransitive gesture planning. In summary, at the hand-independent level, transitive and intransitive actions are represented in a common, left-lateralized praxis network.

Imitation of transitive and intransitive actions in healthy individuals

A handful of patients have been described as being impaired in performing transitive gestures, despite being still able to perform intransitive gestures. This impairment need not be explained by assuming different mechanisms; rather, it can be due to transitive actions being more difficult. In this study we tested whether neurologically healthy participants had greater difficulties in imitating transitive actions with respect to intransitive actions. Consistent with the prediction, subjects imitated intransitive better than transitive gestures. The ease of imitation of intransitive actions supports the complexity account of apraxic impairments.

Gesture Subtype-Dependent Left Lateralization of Praxis Planning: An Event-Related fMRI Study

Ideomotor apraxia is a disorder mainly of praxis planning, and the deficit is typically more evident in pantomiming transitive (tool related) than intransitive (communicative) gestures. The goal of the present study was to assess differential hemispheric lateralization of praxis production using event-related functional magnetic resonance imaging. Voxel-based analysis demonstrated significant activations in posterior parietal cortex (PPC) and premotor cortex (PMC) association areas, which were predominantly left hemispheric, regardless of whether planning occurred for right or left hand transitive or intransitive pantomimes. Furthermore, region of interest-based calculation of mean laterality index (LI) revealed a significantly stronger left lateralization in PPC/PMC clusters for planning intransitive (LI = -0.49 + 0.10, mean + standard deviation [SD]) than transitive gestures (-0.37 + 0.08, P = 0.02, paired t-tests) irrespective of the hand involved. This differential left lateralization for planning remained significant in PMC (LI = -0.47 + 0.14 and -0.36 + 0.13, mean + SD, P = 0.04), but not in PPC (-0.56 + 0.11 and -0.45 + 0.12, P = 0.11), when both regions were analyzed separately. In conclusion, the findings point to a left-hemispheric specialization for praxis planning, being more pronounced for intransitive gestures in PMC, possibly due to their communicative nature.