Sound omission related brain responses in children

Action is an important way for children to learn about the world. Recent theories suggest that action is inherently accompanied by the sensory prediction of its effects. Such predictions can be revealed by rarely omitting the expected sensory consequence of the action, resulting in an omission response that is observable in the EEG. Although prediction errors play an important role in models of learning and development, little is known about omission-related brain responses in children.This study used a motor-auditory omission paradigm, testing a group of 6–8-year-old children and an adult group (N=62). In an identity-specific condition, the sound coupled to the motor action was predictable, while in an identity unspecific condition the sound was unpredictable. Results of a temporal principal component analysis revealed that sound-related brain responses underlying the N1-complex differed considerably between age groups. Despite these developmental differences, omission responses (oN1) were similar between age groups. Two subcomponents of the oN1 were differently affected by specific and unspecific predictions. Results demonstrate that children, independent from the maturation of sound processing mechanisms, can implement specific and unspecific predictions as flexibly as adults. This supports theories that regard action and prediction error as important drivers of cognitive development.

Same Action, Different Meaning: Neural substrates of Semantic Goal Representation

Accurate control over everyday goal-directed actions is mediated by sensory-motor predictions of intended consequences and their comparison with actual outcomes. Such online comparisons of the expected and re-afferent, immediate, sensory feedback are conceptualized as internal forward models. Current predictive coding theories describing such models typically address the processing of immediate sensory-motor goals, yet voluntary actions are also oriented towards long-term conceptual goals and intentions, for which the sensory consequence is sometimes absent or cannot be fully predicted. Thus, the neural mechanisms underlying actions with distal conceptual goals is far from being clear. Specifically, it is still unknown whether sensory-motor circuits also encode information regarding the global meaning of the action, detached from the immediate, movement-related goal. Therefore, using fMRI and behavioral measures, we examined identical actions (either right or left-hand button presses) performed for two different semantic intentions ('yes'/'no' response to questions regarding visual stimuli). Importantly, actions were devoid of differences in the immediate sensory outcome. Our findings revealed voxel patterns differentiating the two semantic goals in the frontoparietal cortex and visual pathways including the Lateral-occipital complex, in both hemispheres. Behavioral results suggest that the results cannot be explained by kinetic differences such as force. To the best of our knowledge, this is the first evidence showing that semantic meaning is embedded in the neural representation of actions independent of immediate sensory outcome and kinetic differences.

Training with Agency-Inspired Feedback from an Instrumented Glove to Improve Functional Grasp Performance

Sensory feedback from wearables can be effective to learn better movement through enhanced information and engagement. Facilitating greater user cognition during movement practice is critical to accelerate gains in motor function during rehabilitation following brain or spinal cord trauma. This preliminary study presents an approach using an instrumented glove to leverage sense of agency, or perception of control, to provide training feedback for functional grasp. Seventeen able-bodied subjects underwent training and testing with a custom-built sensor glove prototype from our laboratory. The glove utilizes onboard force and flex sensors to provide inputs to an artificial neural network that predicts achievement of “secure” grasp. Onboard visual and audio feedback was provided during training with progressively shorter time delay to induce greater agency by intentional binding, or perceived compression in time between an action (grasp) and sensory consequence (feedback). After training, subjects demonstrated a significant reduction (p < 0.05) in movement pathlength and completion time for a functional task involving grasp-move-place of a small object. Future work will include a model-based algorithm to compute secure grasp, virtual reality immersion, and testing with clinical populations.

Analgesics in anaesthetic practice

Each year, approximately 230 million major surgical procedures are undertaken worldwide, with over three-quarters of the patients complaining of pain postoperatively and 10% complaining of severe pain. Pain is not, however, just an unpleasant sensory consequence of surgery, but can also have significant physiological implications impacting negatively on well-being and postoperative outcome. Postoperative pain may also result in changes within the central nervous system, leading to the development of chronic pain states lasting in excess of 3–6 months. Adequate analgesia has proven to be effective when employed in the perioperative period at combating many of these adverse effects. An understanding of the basic physiological and pharmacological mechanisms responsible for producing, transmitting, and sustaining pain has allowed for a variety of effective analgesic agents to be fashioned and used clinically to treat pain. Morphine, the archetypal opioid analgesic, is the most familiar of these agents with a long history of use and evidence of effectiveness; morphine possesses a number-needed-to-treat (NNT) to reduce pain by 50% of around 3 when given in doses of between 10 and 15 mg. Non-steroidal agents and paracetamol are similarly effective in the immediate postoperative period with NNTs of between 2 and 4. More recently, a number of analgesic adjuncts such as gabapentin, pregabalin, ketamine, clonidine, and nefopam have found favour for the treatment of acute postoperative pain. None of these agents, however, are without side-effects, ensuring that the search for effective analgesic agents continues to be a vibrant area of research with new analgesic agents continuing to be developed.

Implicit Agency in Observed Actions: Evidence for N1 Suppression of Tones Caused by Self-made and Observed Actions

Every day we make attributions about how our actions and the actions of others cause consequences in the world around us. It is unknown whether we use the same implicit process in attributing causality when observing others' actions as we do when making our own. The aim of this research was to investigate the neural processes involved in the implicit sense of agency we form between actions and effects, for both our own actions and when watching others' actions. Using an interval estimation paradigm to elicit intentional binding in self-made and observed actions, we measured the EEG responses indicative of anticipatory processes before an action and the ERPs in response to the sensory consequence. We replicated our previous findings that we form a sense of implicit agency over our own and others' actions. Crucially, EEG results showed that tones caused by either self-made or observed actions both resulted in suppression of the N1 component of the sensory ERP, with no difference in suppression between consequences caused by observed actions compared with self-made actions. Furthermore, this N1 suppression was greatest for tones caused by observed goal-directed actions rather than non-action or non-goal-related visual events. This suggests that top–down processes act upon the neural responses to sensory events caused by goal-directed actions in the same way for events caused by the self or those made by other agents.