Effector-independent Representations Guide Sequential Target Selection Biases in Action.

Previous work shows that automatic attention biases toward recently selected target features transfer across action and perception and even across different effectors such as the eyes and hands on a trial-by-trial basis. Although these findings suggest a common neural representation of selection history across effectors, the extent to which information about recently selected target features is encoded in overlapping versus distinct brain regions is unknown. Using fMRI and a priming of pop-out task where participants selected unpredictable, uniquely colored targets among homogeneous distractors via reach or saccade, we show that color priming is driven by shared, effector-independent underlying representations of recent selection history. Consistent with previous work, we found that the intraparietal sulcus (IPS) was commonly activated on trials where target colors were switched relative to those where the colors were repeated; however, the dorsal anterior insula exhibited effector-specific activation related to color priming. Via multivoxel cross-classification analyses, we further demonstrate that fine-grained patterns of activity in both IPS and the medial temporal lobe encode information about selection history in an effector-independent manner, such that ROI-specific models trained on activity patterns during reach selection could predict whether a color was repeated or switched on the current trial during saccade selection and vice versa. Remarkably, model generalization performance in IPS and medial temporal lobe also tracked individual differences in behavioral priming sensitivity across both types of action. These results represent a first step to clarify the neural substrates of experience-driven selection biases in contexts that require the coordination of multiple actions.

Distinct Inhibitory-Control Processes Underlie Children's Judgments of Fairness.

We examined how 5- to 8-year-olds (N = 51; Mage = 83 months; 27 female, 24 male; 69% White, 12% Black/African American, 8% Asian/Asian American, 6% Hispanic, 6% not reported) and adults (N = 18; Mage = 20.13 years; 11 female, 7 male) accepted or rejected different distributions of resources between themselves and others. We used a reach-tracking method to track finger movement in 3D space over time. This allowed us to dissociate two inhibitory processes. One involved pausing motor responses to detect conflict between observed information and how participants thought resources should be divided; the other involved resolving the conflict between the response and the alternative. Reasoning about disadvantageous inequities involved more of the first system, and this was stable across development. Reasoning about advantageous inequities involved more of the second system and showed more of a developmental progression. Generally, reach tracking offers an on-line measure of inhibitory control for the study of cognition.

Continuous action with a neurobiologically inspired computational approach reveals the dynamics of selection history.

Everyday perception-action interaction often requires selection of a single goal from multiple possibilities. According to a recent framework of attentional control, object selection is guided not only by the well-established factors of perceptual salience and current goals but also by selection history. Yet, underlying mechanisms linking selection history and visually-guided actions are poorly understood. To examine such interplay and disentangle the impact of target and distractor history on action selection, we employed a priming-of-popout (PoP) paradigm combined with continuous tracking of reaching movements and computational modeling. Participants reached an odd-colored target among homogeneous distractors while we systematically manipulated the sequence of target and distractor colors from one trial to the next. We observed that current reach movements were significantly influenced by the interaction between attraction by the prior target feature and repulsion by the prior distractor feature. With principal component regression, we found that inhibition led by prior distractors influenced reach target selection earlier than facilitation led by the prior target. In parallel, our newly developed computational model validated that current reach target selection can be explained best by the mechanism postulating the preceded impact of previous distractors followed by a previous target. Such converging empirical and computational evidence suggests that the prior selection history triggers a dynamic interplay between target facilitation and distractor inhibition to guide goal-directed action successfully. This, in turn, highlights the necessity of an explicitly integrated approach to determine how visual attentional selection links with adaptive actions in a complex environment.

Radial bias alters high-level motion perception.

The visual system involves various orientation and visual field anisotropies, one of which is a preference for radial orientations and motion directions. By radial, we mean those directions coursing symmetrically outward from the fovea into the periphery. This bias stems from anatomical and physiological substrates in the early visual system. We recently reported that this low-level visual anisotropy can alter perceived object orientation. Here, we report that radial bias can also alter another higher-level system, the perceived direction of apparent motion. We presented a bistable apparent motion quartet in the center of the screen while participants fixated on various locations around the quartet. Participants (N = 22) were strongly biased to see the motion direction that was radial with respect to their fixation, controlling for any biases with center fixation. This was observed using a vertical-horizontal quartet as well as an oblique quartet (45° rotated quartet). The latter allowed us to rule out the contribution of the hemisphere effect where motion across the midline is perceived less often. These results extend our earlier findings on perceived object orientation, showing that low-level structural aspects of the visual system alter yet another higher-level visual process, that of apparent motion perception.

Motion duration is overestimated behind an occluder in action and perception tasks.

Motion estimation behind an occluder is a common task in situations like crossing the street or passing another car. People tend to overestimate the duration of an object's motion when it gets occluded for subsecond motion durations. Here, we explored (a) whether this bias depended on the type of interceptive action: discrete keypress versus continuous reach and (b) whether it was present in a perception task without an interceptive action. We used a prediction-motion task and presented a bar moving across the screen with a constant velocity that later became occluded. In the action task, participants stopped the occluded bar when they thought the bar reached the goal position via keypress or reach. They were more likely to stop the bar after it passed the goal position regardless of the action type, suggesting that the duration of occluded motion was overestimated (or its speed was underestimated). In the perception task, where participants judged whether a tone was presented before or after the bar reached the goal position, a similar bias was observed. In both tasks, the bias was near constant across motion durations and directions and grew over trials. We speculate that this robust bias may be due to a temporal illusion, Bayesian slow-motion prior, or the processing of the visible-occluded boundary crossing. Understanding its exact mechanism, the conditions on which it depends, and the relative roles of speed and time perception requires further research.

Rethinking Vision and Action.

Action is an important arbitrator as to whether an individual or a species will survive. Yet, action has not been well integrated into the study of psychology. Action or motor behavior is a field apart. This is traditional science with its need for specialization. The sequence in a typical laboratory experiment of see → decide → act provides the rationale for broad disciplinary categorizations. With renewed interest in action itself, surprising and exciting anomalous findings at odds with this simplified caricature have emerged. They reveal a much more intimate coupling of vision and action, which we describe. In turn, this prompts us to identify and dwell on three pertinent theories deserving of greater notice.

Reciprocal facilitation between mental and visuomotor rotations.

Humans exhibit remarkably complex cognitive abilities and adaptive behavior in daily life. Cognitive operation in the "mental workspace," such as mentally rotating a piece of luggage to fit into fixed trunk space, helps us maintain and manipulate information on a moment-to-moment basis. Skill acquisition in the "sensorimotor workspace," such as learning a new mapping between the magnitude of new vehicle movement and wheel turn, allows us to adjust our behavior to changing environmental or internal demands to maintain appropriate motor performance. While this cognitive and sensorimotor synergy is at the root of adaptive behavior in the real world, their interplay has been understudied due to a divide-and-conquer approach. We evaluated whether a separate domain-specific or common domain-general operation drives mental and sensorimotor rotational transformations. We observed that participants improved the efficiency of mental rotation speed after the visuomotor rotation training, and their learning rate for visuomotor adaptation also improved after their mental rotation training. Such bidirectional transfer between two widely different tasks highlights the remarkable reciprocal plasticity and demonstrates a common transformation mechanism between two intertwined workspaces. Our findings urge the necessity of an explicitly integrated approach to enhance our understanding of the dynamic interdependence between cognitive and sensorimotor mechanisms.

Radial Bias Alters Perceived Object Orientation.

Orientation sensitivity is a fundamental property of the visual system, but not all orientations are created equal. For instance, radially oriented stimuli, aligned with a line intersecting the center of gaze, produce greater activity throughout the visual cortex and are associated with greater perceptual sensitivity compared with other orientations. Here, we discuss a robust visual illusion that is likely related to this preference. Using a continuous response measure, participants (N = 36 adults) indicated the gap position in a peripheral Landolt C placed in one of eight orientations and eight locations along four meridians (vertical, horizontal, 45°, 135°). The error distributions revealed that the perceived gap was attracted toward the radial axis. For instance, the gap in a regular C would often be wrongly perceived as tilted 45° corresponding to the oblique meridian where it was placed. These findings demonstrate an unsuspected early-vision influence on the perceived orientation of an object.

Inconsistent attentional contexts impair relearning following gradual visuomotor adaptation.

One of the brain's primary functions is to promote actions in dynamic, distracting environments. Because distractions divert attention from our primary goals, we must learn to maintain accurate actions under sensory and cognitive distractions. Visuomotor adaptation is a learning process that restores performance when sensorimotor capacities or environmental conditions are abruptly or gradually altered. Prior work showed that learning to counteract an abrupt perturbation under a particular single- or dual-task setting (i.e., attentional context) was associated with better recall under the same conditions. This suggested that the attentional context was encoded during adaptation and used as a recall cue. The current study investigated whether the attentional context (i.e., single vs. dual task) also affected adaptation and recall to a gradual perturbation, which limited awareness of movement errors. During adaptation, participants moved a cursor to a target while learning to counteract a visuomotor rotation that increased from 0° to 45° by 0.3° each trial, with or without performing a secondary task. Relearning was impaired when the attentional context was different between adaptation and recall (experiment 1), even when the exposure to the attentional context was limited to the early or late half of adaptation (experiment 2). Changing the secondary task did not affect relearning, indicating that the attentional context, rather than specific stimuli or tasks, was associated with better recall performance (experiment 3). These findings highlight the importance of cognitive factors, such as attention, in visuomotor adaptation and have implications for learning and rehabilitation paradigms.NEW & NOTEWORTHY Adaptation acquired under single- or dual-task setting, which created an undivided or divided attentional context, respectively, was impaired when relearning occurred under different conditions (i.e., shifting from a dual to single task). Changes to the attentional context impaired relearning when the initial adaptation was to a gradual perturbation. Explicit awareness of the perturbation was not necessary for this effect to be robust, nor was the effect attributable to changes in the secondary task requirements.

Target detection and discrimination in pop-out visual search with two targets.

To successfully interact with objects in complex and crowded environments, we often perform visual search to detect or identify a relevant target (or targets) among distractors. Previous studies have reported a redundancy gain when two targets instead of one are presented in a simple target detection task. However, research is scant about the role of multiple targets in target discrimination tasks, especially in the context of visual search. Here, we address this question and investigate its underlying mechanisms in a pop-out search paradigm. In Experiment 1, we directly compared visual search performance for one or two targets for detection or discrimination tasks. We found that two targets led to a redundancy gain for detection, whereas it led to a redundancy cost for discrimination. To understand the basis for the redundancy cost observed in discrimination tasks for multiple targets, we further investigated the role of perceptual grouping (Experiment 2) and stimulus-response feature compatibility (Experiment 3). We determined that the strength of perceptual grouping among homogenous distractors was attenuated when two targets were present compared with one. We also found that response compatibility between two targets contributed more to the redundancy cost compared with perceptual compatibility. Taken together, our results show how pop-out search involving two targets is modulated by the level of feature processing, perceptual grouping, and compatibility of perceptual and response features.

Age-related enhancement in visuomotor learning by a dual-task.

Many daily activities require performance of multiple tasks integrating cognitive and motor processes. While the fact that both processes go through deterioration and changes with aging has been generally accepted, not much is known about how aging interacts with stages of motor skill acquisition under a cognitively demanding situation. To address this question, we combined a visuomotor adaptation task with a secondary cognitive task. We made two primary findings beyond the expected age-related performance deterioration. First, while young adults showed classical dual-task cost in the early motor learning phase dominated by explicit processes, older adults instead strikingly displayed enhanced performance in the later stage, dominated by implicit processes. For older adults, the secondary task may have facilitated a shift to their relatively intact implicit learning processes that reduced reliance on their already-deficient explicit processes during visuomotor adaptation. Second, we demonstrated that consistently performing the secondary task in learning and re-learning phases can operate as an internal task-context and facilitate visuomotor memory retrieval later regardless of age groups. Therefore, our study demonstrated age-related similarities and differences in integrating concurrent cognitive load with motor skill acquisition which, may in turn, contributes to the understanding of a shift in balance across multiple systems.

Modulation of visually guided action by the image and familiar sizes of real-world objects.

In daily life, two aspects of real-world object size perception-the image size of an object and its familiar size in the real world-are highly correlated. Thus, whether these two aspects of object size differently affect goal-directed action (e.g., manual pointing) and how have scarcely been examined. Here, participants reached to touch one of two simultaneously presented objects based on either their image or familiar size, which could be congruent or incongruent (e.g., a rubber duck presented as smaller and larger than a boat, respectively). We observed that when pointing to target objects in the incongruent conditions, participants' movements were slower and were more curved toward the incorrect object compared with the movements in the congruent conditions. By comparing performance in the congruent and incongruent conditions, we concluded that both image size and familiar size influenced action even when task irrelevant, indicating that both are processed automatically (Konkle & Oliva, 2012a). Image size, however, showed influence earlier in the course of movements and more robustly overall than familiar size. We additionally found that greater relative familiar size differences mitigated the impact of image size processing and increased the impact of familiar size processing on pointing movements. Overall, our data suggest that image size and familiar size perception interact both with each other and with visually guided action, but that the relative contributions of each are unequal and vary based on task demands.

Fabrication of plasmonic arrays of nanodisks and nanotriangles by nanotip indentation lithography and their optical properties.

Fabrication of plasmonic nanostructures in a precise and reliable manner is a topic of huge interest because their structural details significantly affect their plasmonic properties. Herein, we present nanotip indentation lithography (NTIL) based on atomic force microscopy (AFM) indentation for the patterning of plasmonic nanostructures with precisely controlled size and shape. The size of the nanostructures is controlled by varying the indentation force of AFM tips into the mask polymer; while their shapes are determined to be nanodisks (NDs) or nanotriangles (NTs) depending on the shapes of the AFM tip apex. The localized surface plasmon resonance of the NDs is tailored to cover most of the visible-wavelength regime by controlling their size. The NTs show distinct polarization-dependent plasmon modes consistent with full-wave optical simulations. For the demonstration of the light-matter interaction control capability of NTIL nanostructures, we show that photoluminescence enhancement from MoS2 layers can be deliberately controlled by tuning the size of the nanostructures. Our results pave the way for the AFM-indentation-based fabrication of plasmonic nanostructures with a highly precise size and shape controllability and reproducibility.

Revealing the effects of temporal orienting of attention on response conflict using continuous movements.

Orienting attention in time enables us to prepare for forthcoming perception and action (e.g., estimating the duration of a yellow traffic light when driving). While temporal orienting can facilitate performance on simple tasks, its influence on complex tasks involving response conflict is unclear. Here, we adapted the flanker paradigm to a choice-reaching task where participants used a computer mouse to reach to the left or right side of the screen, as indicated by the central arrow presented with either the congruent or incongruent flankers. We assessed the effects of temporal orienting by manipulating goal-driven temporal expectation (using probabilistic variations in target timing) and stimulus-driven temporal priming (using sequential repetitions versus switches in target timing). We tested how temporal orienting influenced the dynamics of response conflict resolution. Recent choice-reaching studies have indicated that under response conflict, delayed movement initiation captures the response threshold adjustment process, whereas increased curvature toward the incorrect response captures the degree of coactivation of the response alternatives during the controlled response selection process. Both temporal expectation and priming reduced the initiation latency regardless of response conflict, suggesting that both lowered response thresholds independently of response conflict. Notably, temporal expectation, but not temporal priming, increased the curvature toward the incorrect response on incongruent trials. These results suggest that temporal orienting generally increases motor preparedness, but goal-driven temporal orienting particularly interferes with response conflict resolution, likely through its influence on response thresholds. Overall, our study highlights the interplay between temporal orienting and cognitive control in goal-directed action.

A Combined Alcohol and Smoking Cue-Reactivity Paradigm in People Who Drink Heavily and Smoke Cigarettes: Preliminary Findings.

AIMS: Previous studies have shown that there may be an underlying mechanism that is common for co-use of alcohol and tobacco and it has been shown that treatment for alcohol use disorder can increase rates of smoking cessation. The primary aim of this study was to assess a novel methodological approach to test a simultaneous behavioral alcohol-smoking cue reactivity (CR) paradigm in people who drink alcohol and smoke cigarettes. METHODS: This was a human laboratory study that utilized a novel laboratory procedure with individuals who drink heavily (≥15 drinks/week for men; ≥8 drinks/week for women) and smoke (>5 cigarettes/day). Participants completed a CR in a bar laboratory and an eye-tracking (ET) session using their preferred alcohol beverage, cigarettes brand and water. RESULTS: In both the CR and ET session, there was a difference in time spent interacting with alcohol and cigarettes as compared to water (P's < 0.001), but no difference in time spent interacting between alcohol and cigarettes (P > 0.05). In the CR sessions, craving for cigarettes was significantly greater than craving for alcohol (P < 0.001), however, only time spent with alcohol, but not with cigarettes, was correlated with craving for both alcohol and cigarettes (P < 0.05). CONCLUSION: This study showed that it is feasible to use simultaneous cues during a CR procedure in a bar laboratory paradigm. The attention bias measured in the integrated alcohol-cigarettes ET procedure predicted participants' decision making in the CR. This novel methodological approach revealed that in people who drink heavily and smoke, alcohol cues may affect craving for both alcohol and cigarettes.

Neural Encoding and Representation of Time for Sensorimotor Control and Learning.

The ability to perceive and produce movements in the real world with precise timing is critical for survival in animals, including humans. However, research on sensorimotor timing has rarely considered the tight interrelation between perception, action, and cognition. In this review, we present new evidence from behavioral, computational, and neural studies in humans and nonhuman primates, suggesting a pivotal link between sensorimotor control and temporal processing, as well as describing new theoretical frameworks regarding timing in perception and action. We first discuss the link between movement coordination and interval-based timing by addressing how motor training develops accurate spatiotemporal patterns in behavior and influences the perception of temporal intervals. We then discuss how motor expertise results from establishing task-relevant neural manifolds in sensorimotor cortical areas and how the geometry and dynamics of these manifolds help reduce timing variability. We also highlight how neural dynamics in sensorimotor areas are involved in beat-based timing. These lines of research aim to extend our understanding of how timing arises from and contributes to perceptual-motor behaviors in complex environments to seamlessly interact with other cognitive processes.

Flame Retardant Submicron Particles via Surfactant-Free RAFT Emulsion Polymerization of Styrene Derivatives Containing Phosphorous.

The reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization of diethyl-(4-vinylbenzyl) phosphate (DEVBP) was performed using PEG-TTC as a macro RAFT agent. PEG-TTC (MW 2000, 4000) was synthesized by the esterification of poly (ethylene glycol) methyl ether with a carboxylic-terminated RAFT agent, composed a hydrophilic poly (ethylene glycol) (PEG) block and a hydrophobic dodecyl chain. The RAFT emulsion polymerization of DEVBP was well-controlled with a narrow molecular size distribution. Dynamic light scattering and confocal laser scanning microscopy were used to examine the PEG-b-PDVBP submicron particles, and the length of the PEG chain (hydrophilic block) was found to affect the particle size distribution and molecular weight distribution. The submicron particle size increased with increasing degree of polymerization (35, 65, and 130), and precipitation was observed at a high degree of polymerization (DP) using low molecular weight PEG-TTC (DP 130, A3). The flame retardant properties of the PEG-b-PDVBP were evaluated by thermogravimetric analysis (TGA) and micro cone calorimeter (MCC). In the combustion process, the residue of PEG-b-PDEVBP were above 500 °C was observed (A1 ~ B3, 27 ~ 38%), and flame retardant effect of PEG-b-PDEVBP submicron particles/PVA composite were confirmed by increasing range of temperature and decreasing total heat release with increasing contents of PEG-b-PDEVBP. The PEG-b-PDEVBP submicron particles can provide flame retardant properties to aqueous, dispersion and emulsion formed organic/polymer products.

Application of the "Plan-Do-Study-Act" Model to Improve Survival after Cardiac Arrest in Korea: A Case Study.

OBJECTIVE: Low rates of bystander cardiopulmonary resuscitation (CPR) were identified as a shortcoming in the "chain of survival" for out-of-hospital cardiac arrest (OHCA) care in the Korean city of Ansan. This study sought to evaluate the effect of an initiative to increase bystander CPR and quality of out-of-hospital resuscitation on outcome from OHCA. The post-intervention data were used to determine the next quality improvement (QI) target as part of the "Plan-Do-Study-Act" (PDSA) model for QI. HYPOTHESIS: The study hypothesis was that bystander CPR, return of spontaneous circulation (ROSC), and survival to discharge after OHCA would increase in the post-intervention period. METHODS: This was a retrospective pre/post study. The data from the pre-intervention period were abstracted from 2008-2011 and the post-intervention period from 2012-2013. The effect of the intervention on the odds of ROSC and survival to hospital discharge was determined using a generalized estimating equation to account for confounders and the effect of clustering within medical centers. The analysis was then used to identify other factors associated with outcomes to determine the next targets for intervention in the chain of survival for cardiac arrest in this community. RESULTS: Rates of documented bystander CPR increased from 13% in the pre-intervention period to 37% in the post-intervention period. The overall rate of ROSC decreased from 18.4% to 14.3% (risk difference -4.1%; 95% CI, -7.1%-1.0%), whereas survival to hospital discharge increased from 3.9% to 5.0% (risk difference 1.1%; 95% CI, -1.8%-3.8%), and survival with good neurologic outcome increased from 0.8% to 1.6% (risk difference 0.8%; 95% CI, -0.8%-2.4%). In multivariable analyses, there was no association between the intervention and the rate of ROSC or survival to hospital discharge. The designated level of the treating hospital was a significant predictor of both survival and ROSC. CONCLUSION: In this case study, there were no observed improvements in outcomes from OHCA after the targeted intervention to improve out-of-hospital CPR. However, utilizing the PDSA model for QI, the designated level of the treating hospital was found to be a significant predictor of survival in the post-period, identifying the next target for intervention.

Action Fluency Facilitates Perceptual Discrimination.

Perception and action interact in nearly every moment of daily life. Previous studies have demonstrated not only that perceptual input shapes action but also that various factors associated with action-including individual abilities and biomechanical costs-influence perceptual decisions. However, it is unknown how action fluency affects the sensitivity of early-stage visual perception, such as orientation. To address this question, we used a dual-task paradigm: Participants prepared an action (e.g., grasping), while concurrently performing an orientation-change-detection task. We demonstrated that as actions became more fluent (e.g., as grasping errors decreased), perceptual-discrimination performance also improved. Importantly, we found that grasping training prior to discrimination enhanced subsequent perceptual sensitivity, supporting the notion of a reciprocal relation between perception and action.