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We propose STIMA, a short test for ideo-motor apraxia, allowing us to quantify the apraxic deficit according to action meaning and affected body segment. STIMA is based on a neurocognitive model holding that there are two processes involved in action imitation (i.e., a semantic route for recognizing and imitating known gestures, and a direct route for reproducing new gestures). The test allows to identify which imitative process has been selectively impaired by brain damage (direct vs. semantic route) and possible deficits depending on the body segment involved (hand/limb vs. hand/fingers). N = 111 healthy participants were administered with an imitation task in two separated blocks of known and new gestures. In each block, half of the gestures were performed mainly with the proximal part of the upper limb and the remaining half with the distal one. It resulted in 18 known gestures (nine proximal and nine distal) and 18 new gestures (nine proximal and nine distal) for a total of 36. Each gesture was presented up to a maximum of two times. Detailed criteria are used to assign the final imitation score. Cut offs, equivalent scores and main percentile scores were computed for each subscale. Participants imitated better known than new gestures, and proximal better than distal gestures. Age influenced performance on all subscales, while education only affected one subscale. STIMA is easy and quick to administer, and compared to previous tests, it offers important information for planning adequate rehabilitation programs based on the functional locus of the deficit.

Neuropsychological and neuroimaging studies suggest distinct body representations involved in coding one's and others' body. Other influential theories, however, instead posit a unique model behind coding multisensory information about one's own body and visual information about others. An efficient way to further investigate this issue can be through testing individuals with anomalous anatomical and sensorimotor bodily features. In these people, the representation of their own body is held to be different with respect to the average population due to the peculiar properties of their body, and any experimental finding supposedly mediated by this representation should reflect such difference. We reviewed the most relevant studies reporting individuals with anomalous anatomical and sensorimotor bodily features engaged in (a) handedness task, (b) visual processing of biological motion and (c) visual processing of body shape. The performance in all three kinds of cognitive processes is affected by anomalous body features of the tested populations. However, the reviewed data are also in favor of a body model extrapolated by visual experience of others which mediates processing of biological stimuli and which operates in parallel, or as an alternative, to the representation of one's own body. In light of these results, pure visual and pure embodied accounts behind visual processing of biological stimuli should be reconsidered., (2009 Elsevier Ltd. All rights reserved.)

Recent evidence using a modified Simon task suggests that hand processing involves implicit coding of the spatial position of the hand relative to the side of the body to which it is attached from the viewer's reference point. This effect, called the Sidedness effect, has been found to emerge only when at least the forearm is present (the forearm thus providing the spatial reference for representing the rest of body) and it has been interpreted within the framework of the structural representation of the body. In this study we use the same modified Simon task to investigate whether hand processing involves the implicit access to a spatially and bio-mechanically organized structural body representation. In a first experiment the hand stimuli were attached to a body inappropriately without respecting the bio-mechanical constraints and no Sidedness effect was found. In Experiment 2 where the hand stimuli were presented attached to a non-bodily shape the Sidedness effect was observed only when they were attached appropriately. Whilst previous research has involved explicit representational processes, our results suggest that we can implicit access to a 'structural description of the body' and elaborate the anatomical and bio-mechanical plausibility., (2009 Elsevier Ltd. All rights reserved.)

In this study we investigated with a priming paradigm whether uni and bimanual actions presented as primes differently affected language processing. Animals' (self-moving entities) and plants' (not self-moving entities) names were used as targets. As prime we used grasping hands, presented both as static images and videos. The results showed an interference effect with unimanual action primes (both static and moving) with plants' names. No modulation of responses for animals' names was found. We argue that in the present task plants elicit information on unimanual grasping actions they support, while the lack of effect for animals could be due to them being better characterized as active agents.

The authors used a modified Simon task (J. R. Simon, 1969) to assess the automatic recognition of handedness. Participants responded to the color of a circle in the center of the photograph of a right or a left hand, displayed in the center of the computer screen. A regular Simon effect was found for back views, whereas a reverse Simon effect was found for palm views. This pattern of results was found when the forearm was present (Experiment 2), when 1 finger at a time was rendered invisible (Experiment 3), and when the hands were connected to a body image (Experiment 4). When the hands were cut at the wrist, no effect emerged (Experiment 1). These findings suggest an automatic encoding of the relative position of the hand in relation to the body (imaginary or real) rather than the automatic encoding of handedness.

The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients., (Copyright 2004 APA.)

In this study, we tested whether in certain experimental conditions the distal and proximal motor components may dissociate in action imitation, and how the distal component and the object representation may interact. Experiments 1-3 were carried out using a dual task procedure in which an action span and a motor suppression were coupled. In Experiment 1, it was shown that action spans were affected more by a distal movement (e.g. distal motor suppression) than by a proximal movement (proximal motor suppression). In Experiment 2, it was demonstrated that the reduction of the action spans was not due to the distal motor suppression being more difficult than the proximal motor suppression. In Experiment 3, pantomimes were replaced with the corresponding objects and the participants were asked to mime the objects, reproducing the appropriate actions. During the presentation of the objects, the participants were engaged in a motor suppression that was performed either by the hand or by the arm. The distal motor suppression reduced the pantomime span more significantly than the proximal motor suppression. Experiment 4 showed that the spans of pantomimes of objects shown in Experiment 3 are longer when participants do not perform motor suppressions. Our results suggest that in normal subjects a difference between the distal and the proximal motor component can be observed under dual task conditions and that distal motor suppression seems to interfere both with the encoding of action and with pragmatic representation of objects.