Identity-Based Crossmodal Negative Priming: Aftereffects of Ignoring in One Sensory Modality on Responding to Another Sensory Modality

Negative Priming (NP) refers to the phenomenon that responses towards previously ignored stimuli, as compared to new stimuli, are impaired. That is, NP is reflected in the performance on the probe display of a prime–probe sequence. NP is established in vision, audition and touch. In the current study, we presented participants with auditory, visual, and tactile manifestations of the same temporal patterns in order to measure NP across the senses. On each trial, the sensory modality shifted from the prime to the probe. Each prime and probe display consisted of a target and a distractor stimulus, presented to the same sensory modality. On some trials, the prime distractor repeated as probe target (ignored-repetition trials), on other trials the probe stimuli had not been involved in the prime display (control trials). We observed NP between audition and touch (Experiment 1) and between vision and audition (Experiment 2). These findings indicate that the processes underpinning NP can operate at an amodal, postperceptual level.

Highly Sensitive and Selective Fluorescent Probes for Cu(II) Detection Based on Calix[4]arene-Oxacyclophane Architectures

A new topological design of fluorescent probes for sensing copper ion is disclosed. The calix[4]arene-oxacyclophane (Calix-OCP) receptor, either wired-in-series in arylene-alt-ethynylene conjugated polymers or standing alone as a sole molecular probe, display a remarkable affinity and selectivity for Cu(II). The unique recognition properties of Calix-OCP system toward copper cation stem from its pre-organised cyclic array of O-ligands at the calixarene narrow rim, which is kept in a conformational rigid arrangement by a tethered oxacyclophane sub-unit. The magnitude of the binding constants (Ka = 5.30 − 8.52 × 104 M−1) and the free energy changes for the inclusion complexation (−ΔG = 27.0 − 28.1 kJmol−1), retrieved from fluorimetric titration experiments, revealed a high sensitivity of Calix-OCP architectures for Cu(II) species. Formation of supramolecular inclusion complexes was evidenced from UV-Vis spectroscopy. The new Calix-OCP-conjugated polymers (polymers 4 and 5), synthesized in good yields by Sonogashira–Hagihara methodologies, exhibit high fluorescence quantum yields (ΦF = 0.59 − 0.65). Density functional theory (DFT) calculations were used to support the experimental findings. The fluorescence on–off behaviour of the sensing systems is tentatively explained by a photoinduced electron transfer mechanism.

Evidence for second-order singleton suppression based on probabilistic expectations

Decades of research in attention have shown that salient distractors (e.g., a color singleton) tend to capture attention. However, in most studies, singleton distractors are just as likely to be present as absent. We therefore have little knowledge of how probabilistic expectations of the salient distractor's occurrence and features affect suppression. In three experiments, we explored this question by manipulating the frequency of a singleton distractor and the variability of its color within a search display. We found that increased expectations regarding the occurrence of the singleton distractor eliminated the singleton RT cost and reduced the number of first saccades to the singleton. In contrast, expectations regarding variability in the singleton color did not affect singleton capture. This was surprising and suggests the ability to suppress second order salience over and above that of first order features. We next inserted the probe display that included a to-be-reported letter inside each shape between search trials to measure if attention went to multiple objects. The letter in the singleton location was reported less often in the high frequency condition, suggesting proactive suppression of expected singleton. Additionally, we found that trial-to-trial repetitions of a singleton (irrespective of its color and location) facilitated performance (i.e., singleton repetition priming), but repetitions of its specific color or location did not. Together our findings demonstrate that attentional capture by a color singleton distractor is attenuated by probabilistic expectations of its occurrence, but not of its color and location.

Contralateral Delay Activity Indexes Working Memory Storage, Not the Current Focus of Spatial Attention

Contralateral delay activity (CDA) has long been argued to track the number of items stored in visual working memory (WM). Recently, however, Berggren and Eimer [Berggren, N., & Eimer, M. Does contralateral delay activity reflect working memory storage or the current focus of spatial attention within visual working memory? Journal of Cognitive Neuroscience, 28, 2003–2020, 2016] proposed the alternative hypothesis that the CDA tracks the current focus of spatial attention instead of WM storage. This hypothesis was based on the finding that, when two successive arrays of memoranda were placed in opposite hemifields, CDA amplitude was primarily determined by the position and number of items in the second display, not the total memory load across both displays. Here, we considered the alternative interpretation that participants dropped the first array from WM when they encoded the second array because the format of the probe display was spatially incompatible with the initial sample display. In this case, even if the CDA indexes active storage rather than spatial attention, CDA activity would be determined by the second array. We tested this idea by directly manipulating the spatial compatibility of sample and probe displays. With spatially incompatible displays, we replicated Berggren and Eimer's findings. However, with spatially compatible displays, we found clear evidence that CDA activity tracked the full storage load across both arrays, in line with a WM storage account of CDA activity. We propose that expectations of display compatibility influenced whether participants viewed the arrays as parts of a single extended event or two independent episodes. Thus, these findings raise interesting new questions about how event boundaries may shape the interplay between passive and active representations of task-relevant information.

Design and Synthesis of Fluorescent Betahistine Conjugates with Unique Imaging Property

Labeling cardiovascular drugs probes with a fluorescent tag is an alternative method of measuring drugs activities and distributions in vivo, and further using of advanced tools to diagnose or detect cardiovascular diseases. Using this approach, a fluorescent probe (betahistine-Flu, 1) of Betahistine-based was synthesized and characterized by 1H NMR, 13C NMR and LC-MS, and its UV-Vis absorption spectral and fluorescence spectral, and fluorescence imaging in cell model were investigated. It was found that the fluorescent probe display strong green fluorescence, and have good optical effect in cell. This study reveals a good and interesting results of betahistine-directed fluorescent probe, and its may be a possible candidate for cardiovascular disease diagnosis and analysis in vivo.

The Time-Course of Masked Negative Priming

Negative priming (NP) refers to the finding that reaction times and errors increase when a previously ignored prime distractor is presented as a target. In a variant of this task, the prime display is composed of only a single masked distractor that is followed by the simultaneous presentation of a target and a distractor in the probe display. In one experiment, we explore the time-course of masked NP using different variations of the prime-probe interval (short, medium, and long), and compare the results with time-course investigations of unmasked NP. We found clear evidence for a rapid-decay function of masked NP: With an increase in the prime-probe interval, masked NP decreased. This result is in line with the predictions of the temporal discrimination account and retrieval accounts of NP.

Unattended Distractor-Induced Priming in a Visual Selective Attention Task

Event-related potentials (ERPs) were recorded from 24 subjects in a visual selective-attention task in which two words were each presented both in a prime display and in a probe display with the target word defined by color. Subjects' task for the prime display was a physical one (target word presented in upper or lower case letters), while the probe display task was a lexical decision. In addition to a neutral condition, four conditions were realized by varying the target probe: The target probe word was (1) a repetition of the target prime (attended repetition), (2) a semantically associated word to the target prime (attended semantic), (3) a repetition of the distractor prime (unattended repetition), or (4) a word semantically associated to the distractor prime (unattended semantic). An attended semantic and an attended repetition priming effect was observed by means of both RT and N400. The N400 differentiated between these two attended priming conditions while RT did not. No unattended priming effects were found with behavioral data. The N400 amplitude modulation, however, was also present for unattended priming but was attenuated compared to the attended condition. The data suggest (1) that automatic processes are sufficient to evoke an N400 effect, and (2) that the N400 effect is a more sensitive indicator for priming effects than response times.