Interactive brains

Today’s neuroscience has something to say on the discussion about what makes us humans and how as humans, we do we interact with others. We consider ourselves as humans and thus as moral beings likely because of our capability to represent the future. This capability to make long-distance predictions could be the result of the evolution of a linguistic and symbolic brain, from sensorimotor regions of our phylogenetic ancestors, predictive in nature, originally implicated in action programming and others’ actions understanding, dealing with grammars and syntaxes and computationally trained by the interaction with the others. Evidence in favor of the hypothesis that interactive, communicative, linguistic and symbolic capabilities may have evolved from such a sensorimotor brain will be provided. A sensorimotor brain still surviving under the conscious one and which, differently to the latter, always says the truth

Measuring social capital with a myograph

We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.NeuroEconomics; Social Capital

Measuring social capital with a myograph

We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.We study the behavior of 12 pairs of undergraduate students while they were involved in a simple coordination game requiring motor interaction. Three experimental conditions were defined according to whether a monetary prize was given to both or only one subject, if the couple was in successfully completing the required assignment. Electromyographic potentials (EMG) were recorded from the right first dorsal interosseus (FDI) muscle, a muscle critically involved in the motor task. We also collected written answers from a standard questionnaire from which we constructed individual measures of Social Capital (SC), based on organized group interaction, religious and political involvement. These measures are collected, by standard practice, to estimate individual pro-social attitudes and behavior. Consistently with our simple behavioral model, by which EMG signals are direct measures of subjects’ personal concern (call it utility) associated to the given task, our evidence shows that EMG is increasing in the subjects’ own monetary reward. When we split the subject pool into two subsamples (according to various measures of Social Capital obtained from the questionnaire), we find that monetary incentives explain the level of subjects’ EMG only in the subsample characterized by low SC, while, for subjects with (comparatively) higher SC, effort in the coordination task is much less sensitive to whether it is directly rewarded or not. This result is robust across the different SC index specifications. The present findings seem to support the possibility that an electrophysiological measure, such as EMG, could reveal the most profound attitudes and believes that guide social interaction, and that our relatively inexpensive and ready-to-use technology can back-up socio-economic research in a very effective way.Non-Refereed Working Papers / of national relevance onl

motor cortical inhibition during concurrent action execution and action observation

Abstract Action Execution (AE) and Action Observation (AO) share an extended cortical network of activated areas. During coordinative action these processes also overlap in time, potentially giving rise to behavioral interference effects. The neurophysiological mechanisms subtending the interaction between concurrent AE and AO are substantially unknown. To assess the effect of AO on observer's corticomotor drive, we run one electromyography (EMG) and three Transcranial Magnetic Stimulation (TMS) studies. Participants were requested to maintain a steady hand opening or closing posture while observing the same or a different action (hand opening and closing in the main TMS study). By measuring Cortical Silent Periods (CSP), an index of GABAB-mediated corticospinal inhibitory strength, we show a selective reduction of inhibitory motor drive for mismatching AE-AO pairs. The last two TMS experiments, show that this mismatch is computed according to a muscle-level agonist-antagonist representation. Combined, our results suggest that corticospinal inhibition may be the central neurophysiological mechanism by which one's own motor execution is adapted to the contextual visual cues provided by other's actions

L’origine comune di linguaggio e azione

Riassunto: Il sistema motorio presenta un’organizzazione particolarmente interessante per via delle sue forti analogie con il linguaggio. In questa sede, prendendo spunto dai alcuni studi di neurofisiologia, neuroanatomia e neuroimmagine funzionale, saranno tracciate le similarità più importanti tra l’organizzazione cerebrale del linguaggio e quelle dell’azione. Queste analogie saranno da sostegno per successive speculazioni riguardo ai meccanismi di evoluzione funzionale tra i due sistemi. In particolar modo, suggeriremo che le caratteristiche computazionali alla base del funzionamento del sistema motorio possano aver fornito gli elementi di base per l’emergere della sintassi e semantica nel linguaggio.Parole chiave: Sistema motorio; Gerarchia motoria; Ricorsività; Linguaggio; Azione.  The Shared Origin of Language and Action Abstract: Motor system organization shows some interesting parallels with language organization. Here we point out possible commonalities between Action and Language, basing our claims on neurophysiological, neuroanatomical and neuroimaging data. Furthermore, we speculate that the motor system may have furnished the basic computational capabilities for the emergence of both semantics and syntax.Keywords: Motoric System; Motoric Hierarchy; Recursivity; Language; Action

Superlinear Summation of Information in Premotor Neuron Pairs

Whether premotor/motor neurons encode information in terms of spiking frequency or by their relative time of firing, which may display synchronization, is still undetermined. To address this issue, we used an information theory approach to analyze neuronal responses recorded in the premotor (area F5) and primary motor (area F1) cortices of macaque monkeys under four different conditions of visual feedback during hand grasping. To evaluate the sensitivity of spike timing correlation between single neurons, we investigated the stimulus dependent synchronization in our population of pairs. We first investigated the degree of correlation of trial-to-trial fluctuations in response strength between neighboring neurons for each condition, and second estimated the stimulus dependent synchronization by means of an information theoretical approach. We compared the information conveyed by pairs of simultaneously recorded neurons with the sum of information provided by the respective individual cells. The information transmission across pairs of cells in the primary motor cortex seems largely independent, whereas information transmission across pairs of premotor neurons is summed superlinearly. The brain could take advantage of both the accuracy provided by the independency of F1 and the synergy allowed by the superlinear information population coding in F5, distinguishing thus the generalizing role of F5Instituto de Física de Líquidos y Sistemas Biológico

Interpersonal sensorimotor communication shapes intrapersonal coordination in a musical ensemble

Social behaviors rely on the coordination of multiple effectors within one's own body as well as between the interacting bodies. However, little is known about how coupling at the interpersonal level impacts coordination among body parts at the intrapersonal level, especially in ecological, complex, situations. Here, we perturbed interpersonal sensorimotor communication in violin players of an orchestra and investigated how this impacted musicians' intrapersonal movements coordination. More precisely, first section violinists were asked to turn their back to the conductor and to face the second section of violinists, who still faced the conductor. Motion capture of head and bow kinematics showed that altering the usual interpersonal coupling scheme increased intrapersonal coordination. Our perturbation also induced smaller yet more complex head movements, which spanned multiple, faster timescales that closely matched the metrical levels of the musical score. Importantly, perturbation differentially increased intrapersonal coordination across these timescales. We interpret this behavioral shift as a sensorimotor strategy that exploits periodical movements to effectively tune sensory processing in time and allows coping with the disruption in the interpersonal coupling scheme. As such, head movements, which are usually deemed to fulfill communicative functions, may possibly be adapted to help regulate own performance in time

Face Landmark-based Speaker-Independent Audio-Visual Speech Enhancement in Multi-Talker Environments

In this paper, we address the problem of enhancing the speech of a speaker of interest in a cocktail party scenario when visual information of the speaker of interest is available. Contrary to most previous studies, we do not learn visual features on the typically small audio-visual datasets, but use an already available face landmark detector (trained on a separate image dataset). The landmarks are used by LSTM-based models to generate time-frequency masks which are applied to the acoustic mixed-speech spectrogram. Results show that: (i) landmark motion features are very effective features for this task, (ii) similarly to previous work, reconstruction of the target speaker's spectrogram mediated by masking is significantly more accurate than direct spectrogram reconstruction, and (iii) the best masks depend on both motion landmark features and the input mixed-speech spectrogram. To the best of our knowledge, our proposed models are the first models trained and evaluated on the limited size GRID and TCD-TIMIT datasets, that achieve speaker-independent speech enhancement in a multi-talker setting

The ART of Conversation: Measuring Phonetic Convergence and Deliberate Imitation in L2-Speech with a Siamese RNN

Phonetic convergence describes the automatic and unconscious speech adaptation of two interlocutors in a conversation. This paper proposes a Siamese recurrent neural network (RNN) architecture to measure the convergence of the holistic spectral characteristics of speech sounds in an L2-L2 interaction. We extend an alternating reading task (the ART) dataset by adding 20 native Slovak L2 English speakers. We train and test the Siamese RNN model to measure phonetic convergence of L2 English speech from three different native language groups: Italian (9 dyads), French (10 dyads) and Slovak (10 dyads). Our results indicate that the Siamese RNN model effectively captures the dynamics of phonetic convergence and the speaker's imitation ability. Moreover, this text-independent model is scalable and capable of handling L1-induced speaker variability.Comment: Accepted at INTERSPEECH 202