Evidence accumulation under uncertainty - a neural marker of emerging choice and urgency

To interact meaningfully with its environment, an agent must integrate external information with its own internal states. However, information about the environment is often noisy. In this study, we identify a neural correlate that tracks how asymmetries between competing alternatives evolve over the course of a decision. In our task participants had to monitor a stream of discrete visual stimuli over time and decide whether or not to act, on the basis of either strong or ambiguous evidence. We found that the classic P3 event-related potential evoked by sequential evidence items tracked decision-making processes and predicted participants' categorical choices on a single trial level, both when evidence was strong and when it was ambiguous. The P3 amplitudes in response to evidence supporting the eventually selected option increased over trial time as decisions evolved, being maximally different from the P3 amplitudes evoked by competing evidence at the time of decision. Computational modelling showed that both the neural dynamics and behavioural primacy and recency effects can be explained by a combination of (a) competition between mutually inhibiting accumulators for the two categorical choice outcomes, and (b) a context-dependant urgency signal. In conditions where evidence was presented at a low rate, urgency increased faster than in conditions when evidence was very frequent. We also found that the readiness potential, a classic marker of endogenously initiated actions, was observed preceding movements in all conditions - even when those were strongly driven by external evidence

Imitation and Mirror Systems in Robots through Deep Modality Blending Networks

Learning to interact with the environment not only empowers the agent with manipulation capability but also generates information to facilitate building of action understanding and imitation capabilities. This seems to be a strategy adopted by biological systems, in particular primates, as evidenced by the existence of mirror neurons that seem to be involved in multi-modal action understanding. How to benefit from the interaction experience of the robots to enable understanding actions and goals of other agents is still a challenging question. In this study, we propose a novel method, deep modality blending networks (DMBN), that creates a common latent space from multi-modal experience of a robot by blending multi-modal signals with a stochastic weighting mechanism. We show for the first time that deep learning, when combined with a novel modality blending scheme, can facilitate action recognition and produce structures to sustain anatomical and effect-based imitation capabilities. Our proposed system, can be conditioned on any desired sensory/motor value at any time-step, and can generate a complete multi-modal trajectory consistent with the desired conditioning in parallel avoiding accumulation of prediction errors. We further showed that given desired images from different perspectives, i.e. images generated by the observation of other robots placed on different sides of the table, our system could generate image and joint angle sequences that correspond to either anatomical or effect based imitation behavior. Overall, the proposed DMBN architecture not only serves as a computational model for sustaining mirror neuron-like capabilities, but also stands as a powerful machine learning architecture for high-dimensional multi-modal temporal data with robust retrieval capabilities operating with partial information in one or multiple modalities

Cross-cultural differences in child activities

Item does not contain fulltextActivities of daily living reflect critical contextual influences, operating via toddlers' exposure to culturally influenced learning over the course of early childhood. This chapter discusses the cross-cultural differences of various aspects of play, media exposure, and parent involvement in daily routine. Short-term cultural orientation was associated with more frequent play of both high- and low-intensity. Additionally, parents from more collectivistic cultures reported more TV exposure for their children than did parents from more individualistic cultures. Other, more nuanced patterns emerged as well, and are discussed with regard to existing literature and future exploration

Assessment of the Biocompatibility of Mineral Trioxide Aggregate, Bioaggregate, and Biodentine in the Subcutaneous Tissue of Rats

Objective: The objective of this study was to evaluate the tissue inflammation caused by three endodontic repair materials.Materials and Methods: The materials included micro mega‑mineral trioxide aggregate (MM‑MTA), bioaggregate (BA), and biodentine (BD), which were implanted into the subcutaneous tissue of rats. The tissue samples for histological examination were prepared. The infiltration of lymphocytes and macrophages into the tissue was examined to assess the inflammatory response.Results: Lymphocyte infiltration: A significant increase was detected in the MM‑MTA and BA groups on the 7th and 14th days as compared with the control (7th day P = 0.0001, 14th day P = 0.0176). There was no difference between the groups on the 45th day (P = 0.1730). Lymphocyte infiltration had decreased over time in all groups. Macrophage infiltration: There was a significant increase by the 7th day in the test groups as compared to the control group (P = 0.007). However, there was no difference between the experimental groups on the 14th (P = 0.2708) and 45th (P = 0.1291) days.Conclusion: While MM‑MTA and BA showed a similar biocompatibility, BD was more biocompatible than MM‑MTA and BA in the 1st week of the experiment. However, there was no difference between the materials at the end of the 45th day. MM‑MTA, BA, and BD can be considered suitable endodontic repair materials.Keywords: Bioaggregate, Biocompatible Materials, Biodentine, Endodontic

Cross-cultural differences in child activities

Activities of daily living reflect critical contextual influences, operating via toddlers' exposure to culturally influenced learning over the course of early childhood. This chapter discusses the cross-cultural differences of various aspects of play, media exposure, and parent involvement in daily routine. Short-term cultural orientation was associated with more frequent play of both high- and low-intensity. Additionally, parents from more collectivistic cultures reported more TV exposure for their children than did parents from more individualistic cultures. Other, more nuanced patterns emerged as well, and are discussed with regard to existing literature and future exploration