Neural underpinnings of the interplay between actual touch and action imagination in social contexts

While there is established evidence supporting the involvement of the sense of touch in various actions, the neural underpinnings of touch and action interplay in a social context remain poorly understood. To prospectively investigate this phenomenon and offer further insights, we employed a combination of motor and sensory components by asking participants to imagine exerting force with the index finger while experiencing their own touch, the touch of one another individual, the touch of a surface, and no touch. Based on the assumption that the patterns of activation in the motor system are similar when action is imagined or actually performed, we proceeded to apply a single-pulse transcranial magnetic stimulation over the primary motor cortex (M1) while participants engaged in the act of imagination. Touch experience was associated with higher M1 excitability in the presence and in the absence of force production imagination, but only during force production imagination M1 excitability differed among the types of touch: both biological sources, the self-touch and the touch of one other individual, elicited a significant increase in motor system activity when compared to touching a non-living surface or in the absence of touch. A strong correlation between individual touch avoidance questionnaire values and facilitation in the motor system was present while touching another person, indicating a social aspect for touch in action. The present study unveils the motor system correlates when the sensory/motor components of touch are considered in social contexts

Anticipatory and pre-planned actions: A comparison between young soccer players and swimmers

The present study investigated whether a difference exists in reactive and proactive control for sport considered open or closed skills dominated. Sixteen young (11-12 years) athletes (eight soccer players and eight swimmers) were asked to be engaged into two games competitions that required either a reactive and a proactive type of control. By means of kinematic (i.e. movement time and duration) and dynamic analysis through the force platform (i.e. Anticipatory Postural Adjustments, APAs), we evaluated the level of ability and stability in reacting and anticipating actions. Results indicated that soccer players outperformed swimmers by showing higher stability and a smaller number of falls during the competition where proactive control was mainly required. Soccer players were able to reach that result by anticipating actions through well-modulated APAs. On the contrary, during the competition where reactive control was mainly required, performances were comparable between groups. Therefore, the development of specific action control is already established at 11-12 years of age and is enhanced by the training specificity

The rubber hand illusion in hypnosis provides new insights into the sense of body ownership

Body ownership can be experimentally investigated with the rubber hand illusion (RHI), in which watching a rubber hand stroked synchronously with one's own hidden hand induces a feeling of ownership over the rubber hand. The aim of this study was to investigate response to the RHI in high (N\u2009=\u200921) and low (N\u2009=\u200919) hypnotizable individuals in normal waking state and in hypnosis. Response to the RHI was measured via a question on the illusory feeling of ownership and with proprioceptive drift. The Highs expressed an overall feeling of more ownership over the rubber hand in both the normal waking state and hypnosis, although both groups gave higher ownership scores after synchronous than after asynchronous stroking and the difference between conditions was similar across groups. Conversely, the proprioceptive drift appeared to be differentially modulated by hypnosis and hypnotic suggestibility: it was increased in the Highs and decreased in the Lows after hypnosis induction. These findings hint at an interplay between hypnotic suggestibility and hypnosis in modulating response to the RHI. The selective breakdown of proprioceptive drift among the Lows suggests resistance to recalibrate one's own limb in hypnosis

Olfaction and gustation in blindness: a state of the art of the literature

To date, there are quite a few studies assessing olfaction and gustation in blindness, with great variability in sample size, participants' age, blindness onset and smell and taste evaluation methods. Indeed, the evaluation of olfactory and gustatory performance can differ depending on several factors, including cultural differences. Therefore, here we analysed through a narrative review, all the works reporting a smell and taste assessment in blind individuals during the last 130 years, trying to summarize and address the knowledge in this field

Expert players accurately detect an opponent's movement intentions through sound alone

Sounds offer a rich source of information about events taking place in our physical and social environment. However, outside the domains of speech and music, little is known about whether humans can recognize and act upon the intentions of another agent's actions detected through auditory information alone. In this study we assessed whether intention can be inferred from the sound an action makes, and in turn, whether this information can be used to prospectively guide movement. In 2 experiments experienced and novice basketball players had to virtually intercept an attacker by listening to audio recordings of that player's movements. In the first experiment participants had to move a slider, while in the second one their body, to block the perceived passage of the attacker as they would in a real basketball game. Combinations of deceptive and nondeceptive movements were used to see if novice and/or experienced listeners could perceive the attacker's intentions through sound alone. We showed that basketball players were able to more accurately predict final running direction compared to nonplayers, particularly in the second experiment when the interceptive action was more basketball specific. We suggest that athletes present better action anticipation by being able to pick up and use the relevant kinematic features of deceptive movement from event-related sounds alone. This result suggests that action intention can be perceived through the sound a movement makes and that the ability to determine another person's action intention from the information conveyed through sound is honed through practice. (PsycINFO Database Recor

Postural adjustments to self-triggered perturbations under conditions of changes in body orientation

We studied anticipatory and compensatory postural adjustments (APAs and CPAs) associated with self-triggered postural perturbations in conditions with changes in the initial body orientation. In particular, we were testing hypotheses on adjustments in the reciprocal and coactivation commands, role of proximal vs. distal muscles, and correlations between changes in indices of APAs and CPAs. Healthy young participants stood on a board with full support or reduced support area and held a standard load in the extended arms. They released the load in a self-paced manned with a standard small-amplitude arm movement. Electromyograms of 12 muscles were recorded and used to compute reciprocal and coactivation indices between three muscle pairs on both sides of the body. The subject's body was oriented toward one of three targets: straight ahead, 60° to the left, and 60° to the right. Body orientation has stronger effects on proximal muscle pairs compared to distal muscles. It led to more consistent changes in the reciprocal command compared to the coactivation command. Indices of APAs and CPAs showed positive correlations across conditions. We conclude that the earlier suggested hierarchical relations between the reciprocal and coactivation command could be task-specific. Predominance of negative or positive correlations between APA and CPA indices could also be task-specific

Spinal reflexive movement follows general tau theory

Background: Tau theory explains how both intrinsically and perceptually guided movements are controlled by the brain. According to general tau theory, voluntary, self-paced human movements are controlled by coupling the tau of the movement (i.e., the rate of closure of the movement gap at its current closure rate) onto an intrinsically generated tau-guide (Lee in Ecol Psychol 10:221-250, 1998). To date there are no studies that have looked at involuntary movements, which are directly guided by innate patterns of neural energy generated at the level of the spinal cord or brain, and that can be explained by general tau theory. This study examines the guidance of an involuntary movement generated by the Patellar reflex in presence of a minimized gravitational field. Results: The results showed that the Patellar reflexive movement is strongly coupled to an intrinsic tau-guide particularly when the limb is not moving in the direction of gravity. Conclusion: These results suggest that the same principles of control underpin both voluntary and involuntary movements irrespective of whether they are generated in the brain or the spinal cord. Secondly, given that movements like the patellar reflex are visible from infancy, one might conclude that tau-guidance is an innate form of motor control, or neural blueprint, that has evolved over time. Keywords: Gravitational field; Involuntary movements; Movement planning; Patellar reflex; Tau theor

An exploration on whole-body and foot-based vibrotactile sensitivity to melodic consonance

Consonance is a distinctive attribute of musical sounds, for which a psychophysical explanation has been found leading to the critical band perceptual model. Recently this model has been hypothesized to play a role also during tactile perception. In this paper the sensitivity to vibrotactile consonance was subjectively tested in musicians and non-musicians. Before the test, both such groups listened to twelve melodic intervals played with a bass guitar. After being acoustically isolated, participants were exposed to the same intervals in the form of either a whole-body or foot-based vibrotactile stimulus. On each trial they had to identify whether an interval was ascending, descending or unison. Musicians were additionally asked to label every interval using standard musical nomenclature. The intervals identification as well as their labeling was above chance, but became progressively more uncertain for decreasing consonance and when the stimuli were presented underfoot. Musicians\u2019 labeling of the stimuli was incorrect when dissonant vibrotactile intervals were presented underfoot. Compared to existing literature on auditory, tactile and multisensory perception, our results reinforce the idea that vibrotactile musical consonance plays a perceptual role in both musicians and non-musicians. Might this role be the result of a process occurring at central and/or peripheral level, involving or not activation of the auditory cortex, concurrent reception from selective somatosensory channels, correlation with residual auditory information reaching the basilar membrane through bone conduction, is a question our preliminary exploration leaves open to further research work

Effect of storage on biochemical and microbiological parametersof edible truffle species

The effects of different storage treatments on the most common edible truffle species, such as Tuber magnatum and Tuber borchii (white truffles), Tuber melanosporum and Tuber aestivum (black truffles), were analysed. Biochemical and microbiological profiles were monitored, in order to evaluate possible alterations during truffle preservation. After harvesting, some fresh samples were kept at 4 C for 30 days, other samples were frozen at 20 C for one month, thawed and preserved at 4 C; the remainder were autoclaved. The biochemical parameters studied were sugar and protein content, the activity of some enzymes involved in the central metabolism of the fungi and the electrophoretic pattern of soluble proteins. Total mesophilic bacteria were also counted. The results obtained showed that the storage at 4 C is the treatment that best preserves the biochemical and microbiological characteristics of fresh truffles. Black truffles were more resistant to biochemical spoilage than the white ones, while T. magnatum was the most resistant to microbial spoilage

General tau theory as a model to evaluate audiovisual interplay in interceptive actions

When interacting with the environment, sensory information is essential to guide movements. Picking up the appropriate sensory information (both visual and auditory) about the progression of an event is required to reach the right place at the right time. In this study, we aimed to see if general tau theory could explain the audiovisual guidance of movement in interceptive action (an interception task). The specific contributions of auditory and visual sensory information were tested by timing synchronous and asynchronous audiovisual interplays in successful interceptive trials. The performance was computed by using the tau-coupling model for information-movement guidance. Our findings revealed that while the auditory contribution to movement guidance did change across conditions, the visual contribution remained constant. In addition, when comparing the auditory and visual contributions, the results revealed a significant decrease in the auditory compared to the visual contribution in just one of the asynchronous conditions where the visual target was presented after the sound. This may be because more attention was drawn to the visual information, resulting in a decrease in the auditory guidance of movement. To summarize, our findings reveal how tau-coupling can be used to disentangle the relative contributions of the visual and auditory sensory modalities in movement planning