Abstract concepts and simulated competition.

To better understand the social determinants of conceptual knowledge we devised a task in which participants were asked to judge the match between a definition (expressed in abstract or concrete terms) and a target-word (also either abstract or concrete). The task was presented in the form of a competition that could/could not include an opponent, and in which different percentages of response rounds were assigned to the participant at the experimenter's discretion. Thus, depending on the condition, participants were either exposed to a competitive context mimicking a privileged/unprivileged interaction with the experimenter or to a socially neutral setting. Results showed that manipulation of the social context selectively affected judgments on abstract stimuli: responses were significantly slower whenever a definition and/or a target word were presented in abstract form and when participants were in the favorable condition of responding in most of the trials. Moreover, only when processing abstract material, responses were slower when an opponent was expected to be present. Data are discussed in the frame of the different cognitive engagements involved when treating abstract and concrete concepts as well as in relation to the possible motivational factors prompted by the experimental set-up. The role of social context as a crucial element for abstract knowledge processing is also considered.

Do graspable objects always leave a motor signature? A study on memory traces.

Several studies have reported the existence of reciprocal interactions between the type of motor activity physically performed on objects and the conceptual knowledge that is retained of them. Whether covert motor activity plays a similar effect is less clear. Certainly, objects are strong triggers for actions, and motor components can make the associated concepts more memorable. However, addition of an action-related memory trace may not always be automatic and could rather depend on 'how' objects are encountered. To test this hypothesis, we compared memory for objects that passive observers experienced as verbal labels (the word describing them), visual images (color photographs) and actions (pantomimes of object use). We predicted that the more direct the involvement of action-related representations the more effective would be the addition of a motor code to the experience and the more accurate would be the recall. Results showed that memory for objects presented as words i.e., a format that might only indirectly prime the sensorimotor system, was generally less accurate compared to memory for objects presented as photographs or pantomimes, which are more likely to directly elicit motor simulation processes. In addition, free recall of objects experienced as pantomimes was more accurate when these items afforded actions performed towards one's body than actions directed away from the body. We propose that covert motor activity can contribute to objects' memory, but the beneficial addition of a motor code to the experience is not necessarily automatic. An advantage is more likely to emerge when the observer is induced to take a first-person stance during the encoding phase, as may happen for objects affording actions directed towards the body, which obviously carry more relevance for the actor.

Willingness towards cognitive engagement: a preliminary study based on a behavioural entropy approach.

Faced with a novel task some people enthusiastically embark in it and work with determination, while others soon lose interest and progressively reduce their efforts. Although cognitive neuroscience has explored the behavioural and neural features of apathy, the why's and how's of positive engagement are only starting to be understood. Stemming from the observation that the left hemisphere is commonly associated to a proactive ('do something') disposition, we run a preliminary study exploring the possibility that individual variability in eagerness to engage in cognitive tasks could reflect a preferred left- or right-hemisphere functioning mode. We adapted a task based on response-independent reinforcement and used entropy to characterize the degree of involvement, diversification, and predictability of responses. Entropy was higher in women, who were overall more active, less dependent on instructions, and never reduced their engagement during the task. Conversely, men showed lower entropy, took longer pauses, and became significantly less active by the end of the allotted time, renewing their efforts mainly in response to negative incentives. These findings are discussed in the light of neurobiological data on gender differences in behaviour.

Superstitious beliefs and the associative mind.

Persistence of superstitions in the modern era could be justified by considering them as a by-product of the brain's capacity to detect associations and make assumptions about cause-effect relationships. This ability, which supports predictive behaviour, directly relates to associative learning. We tested whether variability in superstitious behaviour reflects individual variability in the efficiency of mechanisms akin to habit learning. Forty-eight individuals performed a Serial Reaction Time Task (SRTT) or an Implicit Cuing Task (ICT). In the SRTT, participants were exposed to a hidden sequence and progressively learnt to optimize responses, a process akin to skill learning. In the ICT participants met with a hidden association, which (if detected) provided a benefit (cf. habit learning). An index of superstitious beliefs was also collected. A correlation emerged between susceptibility to personal superstitions and performance at the ICT only. This novel finding is discussed in view of current ideas on how superstitions are instated.

Effects of visual motion consistent or inconsistent with gravity on postural sway.

Vision plays an important role in postural control, and visual perception of the gravity-defined vertical helps maintaining upright stance. In addition, the influence of the gravity field on objects' motion is known to provide a reference for motor and non-motor behavior. However, the role of dynamic visual cues related to gravity in the control of postural balance has been little investigated. In order to understand whether visual cues about gravitational acceleration are relevant for postural control, we assessed the relation between postural sway and visual motion congruent or incongruent with gravity acceleration. Postural sway of 44 healthy volunteers was recorded by means of force platforms while they watched virtual targets moving in different directions and with different accelerations. Small but significant differences emerged in sway parameters with respect to the characteristics of target motion. Namely, for vertically accelerated targets, gravitational motion (GM) was associated with smaller oscillations of the center of pressure than anti-GM. The present findings support the hypothesis that not only static, but also dynamic visual cues about direction and magnitude of the gravitational field are relevant for balance control during upright stance.

Memory for past events: movement and action chains in high-functioning autism spectrum disorders.

In the present study, we assessed whether individuals with autism spectrum disorders (ASD) show memory impairments for previously performed actions, as previously suggested for people suffering from obsessive-compulsive disorder (OCD) (Ecker and Engelkamp in Behav Cogn Psychother 23:349-371, 1995; Merckelbach and Wessel in J Nerv Ment Dis 188(12):846-848, 2000). To test this possibility, we explored verbal memory for actions in individuals with a diagnosis of ASD, with and without co-morbidity for OCD, and in controls matched for age and gender. Participants observed or observed and enacted a number of actions while listening to the corresponding phrases being spoken. After a suitable delay, they were submitted to an old/new recognition task. Results showed that ASD individuals with OCD were less accurate and slower in responding compared to ASD individuals without OCD and controls, particularly when dealing with phrases describing simple movements. In contrast, ASD participants without OCD were more impaired when phrases described complex actions that involved pantomiming object use or coordinating movements of multiple body parts. These findings are discussed in terms of differential organization of the motor trace for simple versus complex actions in ASD individuals according to the concurrent presence of OCD.

Watching the Effects of Gravity. Vestibular Cortex and the Neural Representation of "Visual" Gravity.

Gravity is a physical constraint all terrestrial species have adapted to through evolution. Indeed, gravity effects are taken into account in many forms of interaction with the environment, from the seemingly simple task of maintaining balance to the complex motor skills performed by athletes and dancers. Graviceptors, primarily located in the vestibular otolith organs, feed the Central Nervous System with information related to the gravity acceleration vector. This information is integrated with signals from semicircular canals, vision, and proprioception in an ensemble of interconnected brain areas, including the vestibular nuclei, cerebellum, thalamus, insula, retroinsula, parietal operculum, and temporo-parietal junction, in the so-called vestibular network. Classical views consider this stage of multisensory integration as instrumental to sort out conflicting and/or ambiguous information from the incoming sensory signals. However, there is compelling evidence that it also contributes to an internal representation of gravity effects based on prior experience with the environment. This a priori knowledge could be engaged by various types of information, including sensory signals like the visual ones, which lack a direct correspondence with physical gravity. Indeed, the retinal accelerations elicited by gravitational motion in a visual scene are not invariant, but scale with viewing distance. Moreover, the "visual" gravity vector may not be aligned with physical gravity, as when we watch a scene on a tilted monitor or in weightlessness. This review will discuss experimental evidence from behavioral, neuroimaging (connectomics, fMRI, TMS), and patients' studies, supporting the idea that the internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of physical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, stored in the vestibular cortex. The integration of the internal model of gravity with visual and non-visual signals would take place at multiple levels in the cortex and might involve recurrent connections between early visual areas engaged in the analysis of spatio-temporal features of the visual stimuli and higher visual areas in temporo-parietal-insular regions.

The egocentric reference for visual exploration and orientation.

Clinical signs of damage to the egocentric reference system range from the inability to detect stimuli in the real environment to a defect in recovering items from an internal representation. Despite clinical dissociations, current interpretations consider all symptoms as due to a single perturbation, differentially expressed according to the medium explored (perceptual or representational). We propose an alternative account based on the functional distinction between two separate egocentric mechanisms: one allowing construction of the immediate point of view, the other extracting a required perspective within a mental representation. Support to this claim comes from recent results in the domain of navigation, showing that separate cognitive mechanisms maintain the egocentric reference when actively exploring the visual space as opposed to moving according to an internal map. These mechanisms likely follow separate developmental pathways, seemingly depend on distinct neural pathways and are used independently by healthy adults, reflecting task demands and individual cognitive style. Implications for spatial cognition and social skills are discussed.

Remembering actions without proprioception.

It has been suggested that agency signals generated by enactment provide memories with an enduring episodic marker that can successively be exploited to facilitate recall. Current theories of motor awareness highlight the role of prospective and retrospective sensorimotor cues in the construction of sense of agency (SA). To explore how these signals impact on memory for actions, we studied the effect of enactment in a patient with complete loss of somatic sensation below nose level, and compared her performance to that of a group of neurologically intact individuals. A memory advantage for enacted material was clearly detectable in the control group and, interestingly, also in sensory deafferented patient GL. This novel finding shows that robust memory for actions can be obtained even in the absence of somatosensory reafferences. We hypothesize that the neural processes evoked by intention to move, together with visual experience about one's actions, provide the long-lasting agency signals that are responsible for the special quality of self-performed actions and may support autobiographical experience. Proprioceptive cues, being more time-constrained, are critical to online SA but do not necessarily partake in offline action representations.

Altered awareness of voluntary action after damage to the parietal cortex.

A central question in the study of human behavior is the origin of willed action. EEG recordings of surface brain activity from human subjects performing a self-initiated movement show that the subjective experience of wanting to move follows, rather than precedes, the 'readiness potential'--an electrophysiological mark of motor preparation. This raises the issue of how conscious experience of willed action is generated. Here we show that patients with parietal lesions can report when they started moving, but not when they first became aware of their intention to move. This stands in contrast with the performance of cerebellar patients who behaved as normal subjects. We thus propose that when a movement is planned, activity in the parietal cortex, as part of a cortico-cortical sensorimotor processing loop, generates a predictive internal model of the upcoming movement. This model might form the neural correlate of motor awareness.

Asymmetries in initiation of aiming movements in schizophrenia.

Several studies have reported motor symptoms in schizophrenia (SCZ), in some cases describing asymmetries in their manifestation. To date, biases were mainly reported for sequential movements, and the hypothesis was raised of a dopamine-related hemispheric imbalance. Aim of this research is to better characterize asymmetries in movement initiation in SCZ by exploring single actions. Fourteen SCZ patients and fourteen healthy subjects were recruited. On a trial-by-trial basis, participants were instructed to reach for one of eight possible targets. Measures of movement initiation and execution were collected. Starting point, target and moving limb were systematically varied to check for asymmetric responses. Results showed that SCZ patients, besides being overall slower than controls, additionally presented with a bias affecting both the moving hand and the side from which movements were initiated. This finding is discussed in relation to hemispheric lateralization in motor control.

An emotional modulation model as signature for the identification of children developmental disorders.

In recent years, applications like Apple's Siri or Microsoft's Cortana have created the illusion that one can actually "chat" with a machine. However, a perfectly natural human-machine interaction is far from real as none of these tools can empathize. This issue has raised an increasing interest in speech emotion recognition systems, as the possibility to detect the emotional state of the speaker. This possibility seems relevant to a broad number of domains, ranging from man-machine interfaces to those of diagnostics. With this in mind, in the present work, we explored the possibility of applying a precision approach to the development of a statistical learning algorithm aimed at classifying samples of speech produced by children with developmental disorders(DD) and typically developing(TD) children. Under the assumption that acoustic features of vocal production could not be efficiently used as a direct marker of DD, we propose to apply the Emotional Modulation function(EMF) concept, rather than running analyses on acoustic features per se to identify the different classes. The novel paradigm was applied to the French Child Pathological & Emotional Speech Database obtaining a final accuracy of 0.79, with maximum performance reached in recognizing language impairment (0.92) and autism disorder (0.82).

How we interact with objects: learning from brain lesions.

Motor deficits are the most common outcome of brain damage. Although a large part of such disturbances arises from loss of elementary sensorimotor functions, several syndromes cannot be explained purely on these bases. In this article, we briefly describe higher-order motor impairments, with specific attention to the characteristic ability of the human hand to interact with objects and tools. Disruption of this motor skill at several independent levels is used to outline a comprehensive model, in which various current proposals for a modular organization of hand-object interactions can be integrated. In this model, cortical mechanisms related to object interaction are independent from representations of the semantic features of objects.

Reaching for Objects or Asking for Them: Distance Estimation in 7- to 15-Year-Old Children.

This study aims to determine if, in children, subjective perception of space is modulated by the experience of reaching distal objects by means of tools and verbal labels. We presented 7-15-year-old participants with objects located in the near and far space, and in the threshold area between these spaces (border space). Before and after a training session, separate groups of participants estimated objects' location by providing a verbal estimation of their distance (n = 12) or by rolling a toy car to match their location (motor-based estimation; n = 16). The training session required interaction with the targets (i.e., actively experiencing the perceived distance) and included use of a rake or a linguistic label when far objects were involved. A control condition in which training implied use of a short, ineffective tool was also tested (n = 6). Results showed that verbal estimations were not affected by the training phase (p > .05). In contrast, training modulated motor-based estimations relative to border space. Specifically, maximal distance of toy car displacements was reduced following all kinds of training (p < .01). These results indicate that, similarly to adults, the boundary between near and far space is not fixed in children and that both active tool use and verbal labels can modulate this uncertain boundary.

Strength Is in Numbers: Can Concordant Artificial Listeners Improve Prediction of Emotion from Speech?

Humans can communicate their emotions by modulating facial expressions or the tone of their voice. Albeit numerous applications exist that enable machines to read facial emotions and recognize the content of verbal messages, methods for speech emotion recognition are still in their infancy. Yet, fast and reliable applications for emotion recognition are the obvious advancement of present 'intelligent personal assistants', and may have countless applications in diagnostics, rehabilitation and research. Taking inspiration from the dynamics of human group decision-making, we devised a novel speech emotion recognition system that applies, for the first time, a semi-supervised prediction model based on consensus. Three tests were carried out to compare this algorithm with traditional approaches. Labeling performances relative to a public database of spontaneous speeches are reported. The novel system appears to be fast, robust and less computationally demanding than traditional methods, allowing for easier implementation in portable voice-analyzers (as used in rehabilitation, research, industry, etc.) and for applications in the research domain (such as real-time pairing of stimuli to participants' emotional state, selective/differential data collection based on emotional content, etc.).

Processing of visual gravitational motion in the peri-sylvian cortex: Evidence from brain-damaged patients.

Rich behavioral evidence indicates that the brain estimates the visual direction and acceleration of gravity quite accurately, and the underlying mechanisms have begun to be unraveled. While the neuroanatomical substrates of gravity direction processing have been studied extensively in brain-damaged patients, to our knowledge no such study exists for the processing of visual gravitational motion. Here we asked 31 stroke patients to intercept a virtual ball moving along the vertical under either natural gravity or artificial reversed gravity. Twenty-seven of them also aligned a luminous bar to the vertical direction (subjective visual vertical, SVV). Using voxel-based lesion-symptom mapping as well as lesion subtraction analysis, we found that lesions mainly centered on the posterior insula are associated with greater deviations of SVV, consistent with several previous studies. Instead, lesions mainly centered on the parietal operculum decrease the ability to discriminate natural from unnatural gravitational acceleration with a timed motor response in the interception task. Both the posterior insula and the parietal operculum belong to the vestibular cortex, and presumably receive multisensory information about the gravity vector. We speculate that an internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of mechanical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, which are stored in the cortical vestibular network. The present lesion data suggest a specific role for the parietal operculum in detecting the mismatch between predictive signals from the internal model and the online visual signals.

Memory and action: an experimental study on normal subjects and schizophrenic patients.

Psychologists have shown that recall of sentences describing previously performed actions is enhanced compared to recall of heard-only action-phrases (enactment effect). One interpretation of this effect argues that subjects benefit from a multi-modal encoding where movement plays a major role. In line with this motor account, it is conceivable that the beneficial effect of enactment might rely, at least in part, on procedural learning, thus tapping more directly implicit memory functions. Neuropsychological observations support this hypothesis, as shown by the fact that the enactment effect is quite insensitive to perturbations affecting declarative memories. i.e. Alzheimer disease. Memory for subject performed tasks in patients with Korsakoff syndrome. The present study attempts to evaluate whether pure motor activity is sufficient to guarantee the described memory facilitation or alternatively, whether first-person experience in carrying out the action (i.e. true enactment) would be required. To this purpose, in a first experiment on healthy subjects, we tested whether sentence meaning and content of the executed action should match in order to produce facilitation in recall of enacted action-phrases. In a second experiment, we explored whether the enactment effect is present in patients suffering from psychiatric disorders supposed to spare procedural memory but to alter action awareness (e.g. schizophrenia). We show that better recall for action phrases is found only when the motor component is a true enactment of verbal material. Moreover, this effect is nearly lost in schizophrenia. This latter result, on the one hand, queries the automatic/implicit nature of the enactment effect and supports the role of the experience of having performed the action in the first-person. On the other hand, it questions the nature of the memory impairments detected in schizophrenia.

Disadvantageous associations: Reversible spatial cueing effects in a discrimination task.

Current theories describe learning in terms of cognitive or associative mechanisms. To assess whether cognitive mechanisms interact with automaticity of associative processes we devised a shape-discrimination task in which participants received both explicit instructions and implicit information. Instructions further allowed for the inference that a first event would precede the target. Albeit irrelevant to respond, this event acted as response prime and implicit spatial cue (i.e. it predicted target location). To modulate cognitive involvement, in three experiments we manipulated modality and salience of the spatial cue. Results always showed evidence for a priming effect, confirming that the first stimulus was never ignored. More importantly, although participants failed to consciously recognize the association, responses to spatially cued trials became either slower or faster depending on salience of the first event. These findings provide an empirical demonstration that cognitive and associative learning mechanisms functionally co-exist and interact to regulate behaviour.