Efforful verb recollection drives beta suppression in mesial frontal regions involved in action initiation
Language is a uniquely human cognitive function which plays a defining role in our psychological and social traits. Despite the obvious importance of language and speech, they remain one of the least understood human cognitive functions with the cortical underpinnings of these crucial skills still obscure. In recent decades, a large amount of data that account for the neural bases of language processes in both children and adults have been acquired through the use of many advanced neurophysiology techniques. These include high-density electroencephalography, magnetoencephalography, functional magnetic-resonance tomography, transcranial magnetic stimulation, transcranial direct current stimulation, and eye-tracking. The combined use of these approaches continues to shed light on brain mechanisms of language acquisition, comprehension and processing, on speech disorders and their treatment, and on interactions between language and other neurocognitive systems and functions. The aim of this Research Topic in Frontiers in Human Neuroscience is to provide a state-of-the-art overview of this diverse and multidisciplinary area of research, with special emphasis on bridging the gap between different methodologies.
Cognitive control includes maintenance of task-specific processes related to attention, and non-specific regulation of motor threshold. Generally, two different kinds of errors may occur, with some errors related to attentional lapses and decision uncertainty, and some errors – to failures of sustaining motor threshold. Error commission leads to adaptive adjustments in brain networks that subserve goal-directed behavior, resulting in either enhanced stimulus processing or increased motor threshold depending on the nature of errors committed. We report here two studies using the auditory version of the two-choice condensation task, which is highly demanding for sustained attention while involves no inhibition of prepotent responses. We analyzed power and topography of EEG oscillations in theta, alpha, and beta frequency bands.
Experiment 1. We studied post-error adaptive adjustments resulting in optimized brain processing and behaviour on subsequent trials. Errors were followed by increased frontal midline theta (FMT) activity, as well as by enhanced alpha band suppression in the parietal and the left central regions; parietal alpha suppression correlated with the task performance, left central alpha suppression correlated with the post-error slowing, and FMT increase correlated with both behavioral measures. On post-error correct trials, left-central alpha band suppression started earlier before the response, and the response was followed by weaker FMT activity, as well as by enhanced alpha band suppression distributed over the entire scalp. These findings show the existence of three separate neuronal networks involved in post-error adjustments: the midfrontal performance monitoring network, the parietal attentional network, and the sensorimotor network.
Experiment 2. We studied if response time may be a valid approximation distinguishing trials with high and low levels of sustained attention and decision uncertainty. We found that error-related FMT activity was present only on fast erroneous trials. The feedback-related FMT activity was equally strong on slow erroneous and fast erroneous trials. Late post-response posterior alpha suppression was stronger on erroneous slow trials. Feedbackrelated frontal beta oscillations were present only on slow correct trials. The data obtained cumulatively suggests that response time allows distinguishing the two types of trials, with fast trials related to higher levels of attention and low uncertainty, and slow trials related to lower levels of attention and higher uncertainty.
According to embodied cognition theory, speech is largely based on the body motor and sensory experience. The question that is crucial for our understanding of the origin of language is how our brain transforms sensory-motor experience into word meaning. We have developed an auditory-motor experimental procedure that allowed investigating neural underpinning of word meaning acquisition by way of associative "trial-and-error" learning that mimics important aspects of natural word learning. Participants were presented with eight pseudowords; four of them were assigned to specific body part movements during the course of learning – through commencing actions by one of a participant’s left or right extremities and receiving a feedback. The other pseudowords did not require actions and thus were used as controls. A magnetoencephalogram was recorded during passive listening to the pseudowords before and after the learning. The cortical sources of the magnetic evoked responses were reconstructed using distributed source modeling. The learning of novel word meanings through word-action associations selectively increased neural specificity for these words in the auditory parabelt areas responsible for spectrotemporal analysis, as well as in articulatory areas, both located in the left hemisphere. The extent of neural changes was linked to the degree of language learning, specifically implicating the physiological contribution of the left perisylvian cortex in the speech learning success.
The theory of embodied cognition suggests that word meaning resides on the motor and sensory body experience. In order to understand the nature of human language, it is important to decipher how the brain links word meaning with sensory-motor experience. We developed an experimental procedure that allowed investigating acquisition of word meaning by way of rapid associative trial-and-error learning. Eight pseudowords were presented to the participants; four of them were assigned to left and right hand and foot movements, while the other pseudowords did not require actions and were used as controls. Participants were instructed to learn the relations between the pseudowords and actions through a trial-and-error motor learning procedure. Auditory feedback was delivered on each trial informing whether response was correct or erroneous. Magnetoencephalogram was recorded during passive listening of the pseudowords before and after learning. The cortical sources of the magnetic evoked responses were reconstructed using distributed source modeling (MNE software). Neural responses to newly learnt words compared to control pseudowords were significantly enhanced in temporal and frontal cortical regions surrounding the Sylvan fissure of the left hemisphere. This activation was inversely related to the number of trials needed for participants to reach the learning threshold. Thus, our findings revealed a neural signature of rapid associative learning of word meaning and highlighted the role of sensory-motor transformation for association-grounded word semantics.
Supported by RFBR grant 17-29-02168.
Our experimental study looked into the way existing knowledge influences the way subjects con- struct the rules of categorization and modify them as they are applied. We modified the experiment of E. Wisniewski and D. Medina (1994) by asking the respondents not only to create a categorization rule, but also to use it to categorize new images, and we looked at the frequency and type of subsequent rule modification. The respondents, 114 university students, were given a set of images drawn by children and asked to identify their common features under one of the four conditions: relevant prior knowledge (participants were told that the drawings had been made by children with high and low creativity), stan- dard condition (participants were told the drawings had been made by children from groups A and B), standard condition with examples (one sample of drawings from each group was shown), and irrelevant knowledge. We found that under the relevant prior knowledge condition, compared to the other three conditions, the respondents tended to construct more complex and abstract rules and to change them more frequently when they categorized new objects. We also found that rule modifications during usage led to more complex and abstract rules under all four conditions. We interpret the findings as evidence for two stages of categorization, the first stage involving search for existing generalizations in semantic memory, and the second stage involving adaptation of prior knowledge to current conditions.
The distractive effects on attentional task performance in different paradigms are analyzed in this paper. I demonstrate how distractors may negatively affect (interference effect), positively (redundancy effect) or neutrally (null effect). Distractor effects described in literature are classified in accordance with their hypothetical source. The general rule of the theory is also introduced. It contains the formal prediction of the particular distractor effect, based on entropy and redundancy measures from the mathematical theory of communication (Shannon, 1948). Single- vs dual-process frameworks are considered for hypothetical mechanisms which underpin the distractor effects. Distractor profiles (DPs) are also introduced for the formalization and simple visualization of experimental data concerning the distractor effects. Typical shapes of DPs and their interpretations are discussed with examples from three frequently cited experiments. Finally, the paper introduces hierarchical hypothesis that states the level-fashion modulating interrelations between distractor effects of different classes.
This article describes the expierence of studying factors influencing the social well-being of educational migrants as mesured by means of a psychological well-being scale (A. Perrudet-Badoux, G.A. Mendelsohn, J.Chiche, 1988) previously adapted for Russian by M.V. Sokolova. A statistical analysis of the scale's reliability is performed. Trends in dynamics of subjective well-being are indentified on the basis the correlations analysis between the condbtbions of adaptation and its success rate, and potential mechanisms for developing subjective well-being among student migrants living in student hostels are described. Particular attention is paid to commuting as a factor of adaptation.