Neural activity dissociation between thought-based and perception-based response conflict

Based on the idea that intentions have different penetrability to perception and thought (Fodor, 1983), four Stroop-like tasks, AA, AW, WA, and WW are used, where the A represents an arrow and the CPPR (closest processing prior to response) is perception, and the W represents a word and the CPPR is thought. Event-related brain potentials were recorded as participants completed these tasks, and sLORETA (standardized low resolution brain electromagnetic tomography) was used to localize the sources at specific time points. These results showed that there is an interference effect in the AA and WA tasks, but not in the AW or WW tasks. The activated brain areas related to the interference effect in the AA task were the PFC and ACC, and PFC activation took place prior to ACC activation; but only PFC in WA task. Combined with previous results, a new neural mechanism of cognitive control is proposed

Reward improves response inhibition by enhancing attentional capture

Reward plays a crucial role in enhancing response inhibition. While it is generally assumed that the process of response inhibition involves attentional capture and the stopping of action, it is unclear whether this reflects a direct impact of reward on response inhibition or rather an indirect mediation via attentional capture. Here, we employed a revised stop-signal task (SST) that separated these two cognitive elements, by including a continue signal that required the same motor response as in go trials, but also attention to a cue, as in stop trials. We first confirmed the engagement of the right inferior frontal gyrus (IFG) during stop and continue trials, both of which required the attentional capture of the task-relevant cue, but only one of which required motor inhibition. The pre-supplementary motor area (pre-SMA) was specifically activated by the contrast of the stop trials with the continue trials. The results indicated that the IFG played an important role in attentional capture by unexpected stimuli, while the pre-SMA was responsible for the direct control of motor inhibition. Behavioral performance of the SST was improved by reward, and moreover, reward induced an increase in IFG activity. In addition, this advantageous reward effect was associated with enhanced connectivity between the anterior cingulate cortex and the IFG. These results indicated that the reward facilitation effect on response inhibition was indirect, occurring via a change in attentional processing. The present data confirm the specific function of the IFG and pre-SMA in response inhibition and provide straightforward evidence that reward can increase attentional capture-related activation in the IFG, which in turn improves the performance of response inhibition

The neural dynamic mechanisms of asymmetric switch costs in a combined Stroop-task-switching paradigm

Switch costs have been constantly found asymmetrical when switching between two tasks of unequal dominance. We used a combined Stroop-task-switching paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the phenomenon of asymmetrical switch costs. The results revealed that a fronto-central N2 component demonstrated greater negativity in word switch (cW) trials relative to word repeat (wW) trials, and both First P3 and P3b components over the parieto-central region exhibited greater positivity in color switch (wC) trials relative to color repeat (cC) trials, whereas a contrasting switch-related fronto-central SP effect was found to have an opposite pattern for each task. Moreover, the time-frequency analysis showed a right-frontal lower alpha band (9-11 Hz) modulation in the word task, whereas a fronto-central upper alpha band (11-13 Hz) modulation was exclusively found in the color task. These results provide evidence for dissociable neural processes, which are related to inhibitory control and endogenous control, contributing to the generation of asymmetrical switch costs

Surface Structure Enhanced Microchannel Flow Boiling

We investigated the role of surface microstructures in two-phase microchannels on suppressing flow instabilities and enhancing heat transfer. We designed and fabricated microchannels with well-defined silicon micropillar arrays on the bottom heated microchannel wall to promote capillary flow for thin film evaporation while facilitating nucleation only from the sidewalls. Our experimental results show significantly reduced temperature and pressure drop fluctuation especially at high heat fluxes. A critical heat flux (CHF) of 969 W/cm2 was achieved with a structured surface, a 57% enhancement compared to a smooth surface. We explain the experimental trends for the CHF enhancement with a liquid wicking model. The results suggest that capillary flow can be maximized to enhance heat transfer via optimizing the microstructure geometry for the development of high performance two-phase microchannel heat sinks.United States. Office of Naval Research (N00014-15-1-2483)Masdar Institute of Science & Technology - MIT Technology & Development Program (Cooperative agreement, Reference 02/MI/MI/CP/11/07633/GEN/G/00)United States. Air Force Office of Scientific ResearchBattelle Memorial InstituteSingapore-MIT Alliance for Research and Technology (SMART

Automatic prioritization of self-referential stimuli in working memory

People preferentially attend to external stimuli that are related to themselves compared with others. Whether a similar self-reference bias applies to internal representations, such as those maintained in working memory (WM), is presently unknown. We tested this possibility in four experiments, in which participants were first trained to associate social labels (self, friend, stranger) with arbitrary colors and then performed a delayed match-to-sample spatial WM task on color locations. Participants consistently responded fastest to WM probes at locations of self-associated colors (Experiments 1–4). This self-bias was driven not by differential exogenous attention during encoding or retrieval (Experiments 1 and 2) but by internal attentional prioritization of self-related representations during WM maintenance (Experiment 3). Moreover, self-prioritization in WM was nonstrategic, as this bias persisted even under conditions in which it hurt WM performance. These findings document an automatic prioritization of self-referential items in WM, which may form the basis of some egocentric biases in decision making

Identifying the Core Components of Emotional Intelligence: Evidence from Amplitude of Low-Frequency Fluctuations during Resting State

Emotional intelligence (EI) is a multi-faceted construct consisting of our ability to perceive, monitor, regulate and use emotions. Despite much attention being paid to the neural substrates of EI, little is known of the spontaneous brain activity associated with EI during resting state. We used resting-state fMRI to investigate the association between the amplitude of low-frequency fluctuations (ALFFs) and EI in a large sample of young, healthy adults. We found that EI was significantly associated with ALFFs in key nodes of two networks: the social emotional processing network (the fusiform gyrus, right superior orbital frontal gyrus, left inferior frontal gyrus and left inferior parietal lobule) and the cognitive control network (the bilateral pre-SMA, cerebellum and right precuneus). These findings suggest that the neural correlates of EI involve several brain regions in two crucial networks, which reflect the core components of EI: emotion perception and emotional control

All-organic and organic-silicon photonic ring micro-resonators

Organic electro-optic materials offer exceptional processability (both from solution and the gas phase) that permit fabrication of flexible and conformal device structures and the integration of organic materials with a wide range of disparate materials. In addition, organic electro-optical materials have fundamental response times that are in the terahertz region, and useable electro-optic coefficients that are approaching 300 pm/V (at telecommunication wavelengths). In addition to fabrication by traditional lithographic methods, multiple devices on a single wafer have been fabricated by soft and nano-imprint lithography. In this presentation, we review the fabrication and performance evaluation of a number of all-organic and organic-silicon photonic ring microresonator devices. Both electrical and thermal tuning of devices, including both single and multiple ring micro-resonators, are demonstrated

Improving adaptive response to negative stimuli through non-emotional working memory training

People with high working memory (WM) capacity tend to respond proactively and experience a decrease in undesired emotions, implying the potential influence of WM training on emotional responses. Although training emotional WM could enhance emotional control, the training also improves emotional response itself. Thus, the far-transfer effects of non-emotional WM training on emotional responses remain an open question. In the present study, two experiments were conducted to detect these effects. The Preliminary experiment matched the expectations of the gains of the training tasks between the experimental and active control groups (n = 33). In Experiments 1 and 2, participants performed 7-day and 15-day training procedures, respectively. Results indicated that after a 7-day training, non-emotional WM training (n = 17) marginally reduced individuals’ emotional responses compared with the active control group (n = 18); importantly, this improvement became significant after a 15-day training (n(WM training) = 20, n(active control) = 18). A combination analysis for Experiments 1 and 2 showed that training gains on WM performance were significantly related to reduced emotional responses (r = −0.359), indicating a dosage effect. Therefore, non-emotional WM training provides a safe and effective way to enhance adaptive emotional responses

Helminth resistance is mediated by differential activation of recruited monocyte-derived alveolar macrophages and arginine depletion

Macrophages are known to mediate anti-helminth responses, but it remains uncertain which subsets are involved or how macrophages actually kill helminths. Here, we show rapid monocyte recruitment to the lung after infection with the nematode parasite Nippostrongylus brasiliensis. In this inflamed tissue microenvironment, these monocytes differentiate into an alveolar macrophage (AM)-like phenotype, expressing both SiglecF and CD11c, surround invading parasitic larvae, and preferentially kill parasites in vitro. Monocyte-derived AMs (Mo-AMs) express type 2-associated markers and show a distinct remodeling of the chromatin landscape relative to tissue-derived AMs (TD-AMs). In particular, they express high amounts of arginase-1 (Arg1), which we demonstrate mediates helminth killing through L-arginine depletion. These studies indicate that recruited monocytes are selectively programmed in the pulmonary environment to express AM markers and an anti-helminth phenotype

The Motivation-Based Promotion of Proactive Control: The Role of Salience Network

It has been shown that reward motivation can facilitate proactive control, a cognitive control mode that is characterized of prior preparation and sustained holding of the goal-relevant information in working memory. However, it remains to be established the neural networks that may be involved in this promotion effect. In this study, participants underwent the AX-Continuous Performance Task (AX-CPT) that measures relative proactive control during functional magnetic resonance imaging (fMRI) scanning. We employed independent component analysis to decompose multiple brain networks and identified the task related network. Results showed that the salience network (SN) was engaged in the AX-CPT protocol. Importantly, our data demonstrated that reward modulated the association between task engagement of SN and proactive control, whereby the positive correlation was particularly observed in the reward condition. Moreover, reward modulated task engagement of the SN in a proactive manner, which may contribute to the behavioral proactive performance. Overall, our data suggest the involvement of SN in the reward facilitation effect of proactive control