Luisa Sartori

• PhD
• Professor (Assistant) at University of Padua

Complementary colors are color pairs which, when combined in the right proportions, produce white or black. Complementary actions refer here to forms of social interaction wherein individuals adapt their joint actions according to a common aim. Notably, complementary actions are incongruent actions. But being incongruent is not sufficient to be com...

Highly efficient systems are needed to link perception with action in the context of the highly complex environments in which primates move and interact. Another important component is, nonetheless, needed for action: selection. When one piece of fruit from a branch is being chosen by a monkey, many other pieces are within reach and visible: do the...

It is well known that perceiving another's body movements activates corresponding motor representations in an observer's brain. It is nevertheless true that in many situations simply imitating another's actions would not be an effective or appropriate response, as successful interaction often requires complementary rather than emulative movements....

Newborns come into the world wired to socially interact. Is a propensity to socially oriented action already present before birth? Twin pregnancies provide a unique opportunity to investigate the social pre-wiring hypothesis. Although various types of inter-twins contact have been demonstrated starting from the 11(th) week of gestation, no study ha...

Every day, we make thousands of finger movements on the touchscreen of our smartphones. The same movements might be directed at various distal goals. We can type “What is the weather in Rome?” in Google to acquire information from a weather site, or we may type it on WhatsApp to decide whether to visit Rome with a friend. In this study, we show tha...

Simple Summary Humans have the amazing ability to make thousands of different facial expressions due to the existence of two different brain pathways for facial expressions: The Voluntary Pathway, which controls intentional expressions, and the Involuntary Pathway, which is activated for spontaneous expressions. These two pathways could also differ...

Humans can recombine thousands of different facial expressions. This variability is due to the ability to voluntarily or involuntarily modulate emotional expressions, which, in turn, depends on the existence of two anatomically separate pathways. The Voluntary (VP) and Involuntary (IP) pathways mediate the production of posed and spontaneous facial...

Simple Summary Scientific evidence has demonstrated that in social contexts the motor system integrates predictions about the actions of others and plans the most appropriate responses. However, it is not yet known how these processes are reflected in the modulation of excitatory and inhibitory corticospinal mechanisms. Our goal was to reveal the b...

Probing the brain structure–function relationship is at the heart of modern neuroscientific explorations, enabled by recent advances in brain mapping techniques. This study aimed to explore the anatomical blueprint of corticospinal excitability and shed light on the structure–function relationship within the human motor system. Using diffusion magn...

The aim of the present study was to investigate the effect of Tai Chi (TC) and mental imagery (MI) on motor performance. MI is the ability of representing different types of images and it can be improved through constant practice (e.g., of TC). The majority of previous literature has mainly investigated the impact of this mental factor by means of...

The finding of reasonably consistent spatial and temporal productions of actions across different body parts has been used to argue in favor of the existence of a high-order representation of motor programs. In these terms, a generalized motor program consists of an abstract memory structure apt to specify a class of non-specific instructions used...

Although observing other’s gaze and body movements provides a crucial source of information to successfully interact with other people, it remains unclear whether observers weigh differently these cues and whether the convergence of gaze and body’s directions determines facilitation effects. Here we aim to shed more light on this issue by testing t...

Many daily activities involve synchronizing with other people’s actions. Previous literature has revealed that a slowdown of performance occurs whenever the action to be carried out is different to the one observed (i.e., visuomotor interference). However, action execution can be facilitated by observing a different action if it calls for an intera...

According to available evidence, after making an erroneous decision people tend to slow down on the next decision. This empirical regularity, known as "post error slowing" (PES), has been traditionally interpreted as the result of a conservative response criterion adopted to avoid future errors and it is supposed to be driven by changes in the exci...

Direct gaze is a powerful social cue able to capture the onlooker’s attention. Beside gaze, head and limb movements as well can provide relevant sources of information for social interaction. This study investigated the joint role of direct gaze and hand gestures on onlookers corticospinal excitability (CE). In two experiments we manipulated the te...

The aim of the present study was to investigate the correlation between corticospinal activity, kinematics, and electromyography (EMG) associated with the execution of precision and whole-hand grasps (WHGs). To this end, motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS), EMG, and 3-D motion capture data have been sim...

Focal hand dystonia in musicians is a neurological motor disorder in which aberrant plasticity is caused by excessive repetitive use. This work’s purposes were to induce plasticity changes in a dystonic musician through five daily thirty-minute sessions of 1 Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left M1 by using neur...

Humans represent symbolic numbers as oriented from left to right: the mental number line (MNL). Up to now, scientific studies have mainly investigated the MNL by means of response times. However, the existing knowledge on the MNL can be advantaged by studies on motor patterns while responding to a number. Cognitive representations, in fact, cannot...

Neurophysiological studies showed that in macaques, grasp-related visuomotor transformations are supported by a circuit involving the anterior part of the intraparietal sulcus, the ventral and the dorsal region of the premotor area. In humans, a similar grasp-related circuit has been revealed by means of neuroimaging techniques. However, the majori...

In the past decade hand kinematics has been reliably adopted for investigating cognitive processes and disentangling debated topics. One of the most controversial issues in numerical cognition literature regards the origin – cultural vs. genetically driven – of the mental number line (MNL), oriented from left (small numbers) to right (large numbers...

Consistent evidence suggests that the way we reach and grasp an object is modulated not only by object properties (e.g., size, shape, texture, fragility and weight), but also by the types of intention driving the action, among which the intention to interact with another agent (i.e., social intention). Action observation studies ascribe the neural...

Single subject kinematic parameters in individual condition. (PDF)

Single subject kinematic parameters in social condition. (PDF)

Observing moving body parts can automatically activate topographically corresponding motor representations in the primary motor cortex (M1), the so-called direct matching. Novel neurophysiological findings from social contexts are nonetheless proving that this process is not automatic as previously thought. The motor system can flexibly shift from...

Speeded responses to an external cue are slower when the cue interrupts preparation to perform the same or a similar action in a self-paced manner. To explore the mechanism underlying this ‘cost of intention’, we examined whether the size of the cost is influenced by the nature of the external cue. Specifically, we assessed whether the cost of inte...

When a monkey selects a piece of food lying on the ground from among other viable objects in the near vicinity, only the desired item governs the particular pattern and direction of the animal’s reaching action. It would seem then that selection is an important component controlling the animal’s action. But, we may ask, is the selection process in...

Leibovich et al. argue that it is impossible to control for all continuous magnitudes in a numerical task. We contend that continuous magnitudes (i.e., perimeter, area, density) can be simultaneously controlled. Furthermore, we argue that shedding light on the interplay between number and continuous magnitudes – rather than considering them indepen...

Human beings come into the world wired for social interaction. At the fourteenth week of gestation, twin fetuses already display interactive movements specifi cally directed towards their co-twin. Readiness for social interaction is also clearly expressed by the newborn who imitates facial gestures, suggesting that there is a common representation...

Humans show a remarkable tendency to describe and think of numbers as being placed on a mental number line (MNL), with smaller numbers located on the left and larger ones on the right. Faster responses to small numbers are indeed performed on the left side of space, while responses to large numbers are facilitated on the right side of space (spatia...

Motor resonance is defined as the subliminal activation of the motor system while observing actions performed by others. However, resonating with another person's actions is not always an appropriate response: In real life, people do not just imitate but rather respond in a suitable fashion. A growing body of neurophysiologic studies has demonstrat...

A large body of research indicates that observing actions made by others is associated with corresponding motor facilitation of the observer's corticospinal system. However, it is still controversial whether this matching mechanism strictly reflects the kinematics of the observed action or its meaning. To test this issue, motor evoked potentials (M...

The aim of the present study was to investigate the effect of observing other’s movements on subsequent performance in bottlenose dolphins. The imitative ability of non-human animals has intrigued a number of researchers. So far, however, studies in dolphins have been confined to intentional imitation concerned with the explicit request to imitate...

The most popular model to explain how prehensile movements are organized assumes that they comprise two "components", the reaching component encoding information regarding the object's spatial location and the grasping component encoding information on the object's intrinsic properties such as size and shape. Comparative kinematic studies on graspi...

Action observation and execution share overlapping neural substrates, so that simultaneous activation by observation and execution modulates motor performance. Previous literature on simple prehension tasks has revealed that motor influence can be two-sided: facilitation for observed and performed congruent actions and interference for incongruent...

Recording of neural activity during grasping actions in macaques showed that grasp-related sensorimotor transformations are accomplished in a circuit constituted by the anterior part of the intraparietal sulcus (AIP), the ventral (F5) and the dorsal (F2) region of the premotor area. In humans, neuroimaging studies have revealed the existence of a s...

Motor resonance is defined as the internal activation of an observer's motor system, specifically attuned to the perceived movement. In social contexts, however, different patterns of observed and executed muscular activation are frequently required. This is the case, for instance, of seeing a key offered with a precision grip and received by openi...

Experimental evidence suggests the existence of a sophisticated brain circuit specifically dedicated to reach-to-grasp planning and execution, both in human and non-human primates (Castiello, 2005). Studies accomplished by means of neuroimaging techniques suggest the hypothesis of a dichotomy between a “reach-to-grasp” circuit, involving the anteri...

Human beings come into the world wired for social interaction. As has been observed in mimicry, priming, and automatic imitation, indeed, humans are remarkably efficient at resonating with one another. In specific contexts that require incongruent, complementary (from Latin complemèntum; i.e., that fills up) rather than imitative forms of interacti...

This study used the transcranial magnetic stimulation/motor evoked potential (TMS/MEP) technique to pinpoint when the automatic tendency to mirror someone else's action becomes anticipatory simulation of a complementary act. TMS was delivered to the left primary motor cortex corresponding to the hand to induce the highest level of MEP activity from...

Although there is a wealth of behavioral data regarding grasping movements in non-human primates, how posture influences the kinematics of prehensile behavior is not yet clearly understood. The purpose of this study was to examine and compare kinematic descriptions of grip behaviors while primates (macaque monkeys) were in a sitting posture or when...

Building on the extensive cognitive science literature on the subject, this paper introduces a model of the brain mechanisms underly-ing social interactions in humans and other primates. The fundamental components of the model are the "Action Observation" and "Action Planning" Systems, dedicated respectively to interpreting/recognizing the partner'...

It is well known that perceiving another person's body movements activates corresponding motor representations in an observer's brain, a process which appears to be imitative in nature. However, it is also true that simply imitating another person's action/s in many situations is not an effective or appropriate response, as successful interaction o...

Humans show a spontaneous tendency to increase the velocity of their movements depending on the linear extent of their trajectory in order to keep execution time approximately constant. Termed the isochrony principle, this compensatory mechanism refers to the observation that the velocity of voluntary movements increases proportionally with their l...

The idea of motor resonance was born at the time that it was demonstrated that cortical and spinal pathways of the motor system are specifically activated during both action-observation and execution. What is not known is if the human action observation-execution matching system simulates actions through motor representations specifically attuned t...

Mirror neurons are a class of visuo-motor neurons activated by both the execution and passive observation of object-related actions. Evidence for the existence of mirror neurons in the human brain comes in part from transcranial magnetic stimulation studies showing that observation of an action causes subliminal activation of corresponding corticos...

The MUNDUS system is a complex assistive device aimed at supporting the daily life of persons with severe motor disabilities by allowing autonomous reaching and grasping of objects even in the case of complete paralysis of the upper limbs. To permit the performing of different tasks, it is necessary, among other activities, an effective recognition...

The prehensile hand is one of the major traits distinguishing primates from other mammal species. All primates, in fact, are able to grasp an object and hold it in part or entirely using a single hand. Although there is a wealth of behavioral data regarding grasping movements in humans and apes, there is relatively little material on macaques, the...

Because the way we grasp an object varies depending on the intention with which the object is grasped, monitoring the properties of prehensile movements may provide access to a person's intention. Here we investigate the role of visual kinematics in the implicit coding of intention, by using functional brain imaging while participants observed gras...

Skepticism has been expressed concerning the possibility to understand others' intentions by simply observing their movements: since a number of different intentions may have produced a particular action, motor information—it has been argued—might be sufficient to understand what an agent is doing, but not her remote goal in performing that action....

Substantial literature has demonstrated that how the hand approaches an object depends on the manipulative action that will follow object contact. Little is known about how the placement of individual fingers on objects is affected by the end-goal of the action. Hand movement kinematics were measured during reaching for and grasping movements towar...

When someone is choosing one piece from a bowl full of fruit, many pieces are within reach and visible. Although the desired piece seems to govern the particular pattern and direction of that person's reaching movement, the selection process is not impervious to the presence of task-irrelevant information (i.e. the other fruits). Evidence suggests...

A large body of research reports that perceiving body movements of other people activates motor representations in the observer's brain. This automatic resonance mechanism appears to be imitative in nature. However, action observation does not inevitably lead to symmetrical motor facilitation: Mirroring the observed movement might be disadvantageou...

Although facilitation of the corticospinal system during action observation is widely accepted, it remains controversial whether this facilitation reflects a replica of the observed movements or the goal of the observed motor acts. In the present study, we asked whether, when an object is grasped by using a tool, corticospinal facilitation represen...

Transcranial magnetic stimulation (TMS) studies have shown that the observation of an action causes subliminal activation within the motor system. However, the issue of whether such an effect is modulated by the match between the observed action and that the observer would have exhibited if acting under similar circumstances remains unclear. We add...

Body movement provides a rich source of information about other people's goals and intentions. In the present study, we examined a particular aspect concerned with the interpretation of bodily movement--how well people can distinguish between different social intentions by observing a reach-to-grasp movement. To ascertain to what extent intention-f...

A large body of research reports that perceiving body movements of other people activates motor representations in the observer's brain. This automatic resonance mechanism appears to be imitative in nature. However, action observation does not inevitably lead to symmetrical motor facilitation: mirroring the observed movement might be disadvantageou...

Body movement provides a rich source of cues about other people's goals and intentions. In the present research, we investigate how well people can distinguish between different social intentions on the basis of movement information. Participants observed a model reaching toward and grasping a wooden block with the intent to cooperate with a partne...

Humans spend most of their time interacting with other people. It is the motor organization subtending these social interactions that forms the main theme of this article. We review recent experimental studies testing whether it is possible to differentiate the kinematics of an action performed by an agent acting in isolation from the kinematics of...

Four experiments investigated the influence of a sudden social request on the kinematics of a preplanned action. In Experiment 1, participants were requested to grasp an object and then locate it within a container (unperturbed trials). On 20% of trials, a human agent seated nearby the participant unexpectedly stretched out her arm and unfolded her...

The aim of the present study was to investigate the effects of communicative intention on action. In Experiment 1 participants were requested to reach towards an object, grasp it, and either simply lift it (individual condition) or lift it with the intent to communicate a meaning to a partner (communicative condition). Movement kinematics were reco...

The aim of the present study was to investigate the effects of social intentions on action. Participants (N=13) were requested to reach towards, grasp an object, and either pass it to another person (social condition) or put it on a concave base (single-agent condition). Movements' kinematics was recorded using a three-dimensional motion analysis s...

The aim of the present study is to ascertain whether in a social context the kinematic parameters are influenced by the stance of the participants. In particular, we consider two basic modes of social cognition, namely cooperation and competition. Naïve subjects were asked either to cooperate or to compete with a partner (a professional female acto...

This study reports the results of one experiment and a replication, aimed at investigating heart rate changes related to a purely intuitive task. In each experiment, 12 subjects were required to guess which of four pictures presented in sequence for about 10 s was the target. Each subject performed 20 trials. In each trial, the target was automatic...

This study reports the results of one experiment and a replication, aimed at investigating heart rate changes related to a pure intuition task. In each experiment, twelve subjects were required to guess which of the four pictures presented in sequence for about 10 seconds, was the target. Each subject performed 20 trials. In each trial the target w...

Physiological reactions to incoming stimuli can occur without perceptual and cognitive encoding. This paper reports the results of two experiments aimed at investigating heart rate differences in participants on viewing targets and nontargets in classical clairvoyance and precognition forced-choice tasks. We opted for very easy decision-making task...

Are intentions – and social intention, in particular – translated into motor patterns? The present thesis provides an attempt to indagate interactive minds and the mechanisms underlying such phenomenon from a behavioural perspective, by adopting a motor control approach. Our findings suggest that prior social intentions translate into specific mot...