Nematic liquid crystals lack positional order of their constituent molecules, which share an average orientational order only. Modulated nematic liquid crystal phases also lack positional order, but ...possess a periodic variation in this direction of average orientation. In the recently discovered splay nematic (N
S
) phase the average orientational order is augmented with a periodic splay deformation of orientation perpendicular to the director. In this communication we report the first example of a splay nematic phase which is chemically induced by mixing two materials, neither of which exhibit the N
S
phase. The splay-nematic phase is identified based on its optical textures, X-ray scattering patterns, and small enthalpy of the associated phase transition. We measure the splay periodicity optically, finding it to be ∼9 μm. This unexpected generation of the splay-nematic phase through binary mixtures offers a new route to materials which exhibit this phase which complements ongoing studies into structure-property relationships and could accelerate the development of technologies utilising this remarkable polar nematic variant.
We find that the splay nematic phase can be chemically induced in binary mixtures of two materials, neither of which exhibits the splay nematic phase in their neat state.
In the present study, we report the results from a large sample of participants (N = 136), selected based on their EEG quality, to obtain event-related potential (ERP) normative data. All ...participants were tested in Simple Response Task (SRT) and Discriminative Response Task (DRT). A subset of 36 participants was tested also in Passive Vision task. Both pre- and post-stimulus ERPs were analyzed and compared among different tasks. Spatiotemporal patterns of all the observed components were analyzed using source analysis. Beside the well-known ERP components, we also described recently identified prefrontal components: the pre-stimulus prefrontal negativity (pN) associated to proactive cognitive (mainly inhibitory) control within the inferior frontal gyrus (iFg); the post-stimulus prefrontal N1, P1 and P2 (pN1, pP1 and pP2) involved in perceptual and visual-motor awareness (pN1 and pP1), and in stimulus-response mapping and decision-making (pP2) localized within the insular cortex. The large sample of high-quality EEG datasets allowed to identify four additional components: the pre-stimulus visual negativity (vN) originating in extrastriate visual areas and interpreted as a visual readiness activity; the post-stimulus prefrontal N2 and N3 (pN2 and pN3) components interpreted as feedback reactivation of the anterior insular cortex; and the post-stimulus prefrontal P3 (pP3), interpreted as persisting inhibitory activity of the iFg for inhibited trials.
•Normative ERP data were obtained from 136 participants in simple and complex tasks.•The pre- (pN) and post-stimulus (pN1, Pp1, Pp2) components were especially described.•A passive vision task allowed to detect a pre-stimulus occipital vN component.•We showed new ways to study cognition in prefrontal and insular cortex using ERP.
Across development, people tend to demonstrate a preference for contexts in which they have the opportunity to make choices. However, it is not clear how children, adolescents, and adults learn to ...calibrate this preference based on the costs and benefits of agentic choice. Here, in both a primary, in-person, reinforcement-learning experiment ( N = 92; age range = 10–25 years) and a preregistered online replication study ( N = 150; age range = 8–25 years), we found that participants overvalued agentic choice but also calibrated their agency decisions to the reward structure of the environment, increasingly selecting agentic choice when choice had greater instrumental value. Regression analyses and computational modeling of participant choices revealed that participants’ bias toward agentic choice—reflecting its intrinsic value—remained consistent across age, whereas sensitivity to the instrumental value of agentic choice increased from childhood to early adulthood.
Both children and adults are more likely to remember information when they have control over their learning environment. Despite many demonstrations of this effect in the literature, it is still ...unclear how and why people are more likely to remember information that is obtained through their own actions rather than passively received. One possibility is that individuals are biased to remember the outcomes of their choices because doing so may often be beneficial. Having agency, or the ability to exert control, is valuable when individuals can act in an instrumental manner to achieve their goals. Preferentially encoding information encountered in such contexts may confer an advantage when making similar decisions in the future. However, it has not been directly examined whether modulating the value, or utility, of agency affects its mnemonic benefit. Additionally, the developmental trajectory of how the utility of agency affects memory is unclear. The current study examines whether the mnemonic benefit of agency is modulated by the utility of choice and whether this effect varies as a function of age. We tested 96 participants, ages 8 to 25, in a paradigm in which agency and its utility were separately manipulated at encoding. In contrast to previous studies, we did not find that simply having the ability to make a choice enhanced memory. Rather, when the utility of agency varied within the task, we only observed an agency-related memory benefit when the ability to choose had the greatest utility. This pattern was age-invariant, suggesting that this effect on memory is present in middle childhood and persists through adulthood.
•The ability to choose and the value of making choices were separately manipulated in a novel learning paradigm.•Participants had better memory after 24 h when their choices were valuable than when their choices were less consequential.•The memory benefit of valuable choice did not vary throughout our age range of 8 to 25 years.
...understanding decisional processes, and reasons of decision failure, would be helpful to clarify the executive dysfunctions of clinical conditions such as obsessive compulsive disorders, ...impulsivity, and addictions (typically intended as a failure of inhibition; Chamberlain et al., 2005; Crews and Boettiger, 2009; Álvarez-Moya et al., 2011), as well as success in real-life tasks (e.g., car driving; Bunce et al., 2012) and goal-directed behaviors (e.g., complying with diet schedules; Jahanshahi et al., 2015). ...except for the motor preparation activities of the frontal areas, as reflected by the Bereitschaftspotential (BP; e.g., Shibasaki and Hallett, 2006) and the lateralized readiness potential (LRP; e.g., Rinkenauer et al., 2004), only the very recent literature started to report the ERP correlates of the PFC in the executive functioning and variability (for a review see Di Russo et al., 2017). Looking into the Frontal Lobes: Emerging Evidence on the ERP Correlates of Executive Functions When performing a decision-making task, the contribution of the PFC executive functions is manifested mainly through cognitive processes like top-down attentional control, maintenance of information in the short-term memory, ability to ignore distractors and focus on relevant features, and inhibition of the wrong schema and selection of the appropriate one. Since even one of these processes would be able to affect the inter- and intra-individual variability of the performance, they should be dissociated and investigated separately. A prefrontal activity compatible with the pN was described by West and Alain (2000) adopting a Stroop task: findings are consistent in revealing that momentary lapses of attention are associated with a pre-stimulus change in the ERP activity over the frontal regions. ...it was shown that also inter-individual variability of performance was associated with the individual level of pN activity: in other words, the more consistent performers are marked by larger pN activity than the less consistent ones (Perri et al., 2015a).
Adaptive memory requires context-dependent control over how information is retrieved, evaluated and used to guide action, yet the signals that drive adjustments to memory decisions remain unknown. ...Here we show that prediction errors (PEs) coded by the striatum support control over memory decisions. Human participants completed a recognition memory test that incorporated biased feedback to influence participants' recognition criterion. Using model-based fMRI, we find that PEs-the deviation between the outcome and expected value of a memory decision-correlate with striatal activity and predict individuals' final criterion. Importantly, the striatal PEs are scaled relative to memory strength rather than the expected trial outcome. Follow-up experiments show that the learned recognition criterion transfers to free recall, and targeting biased feedback to experimentally manipulate the magnitude of PEs influences criterion consistent with PEs scaled relative to memory strength. This provides convergent evidence that declarative memory decisions can be regulated via striatally mediated reinforcement learning signals.
Vernal keratoconjunctivitis (VKC) is a severe disease with a prevalence of < 1 case out of 10,000 in Europe, which occurs mainly in pediatric age and is characterized by a severe and often bilateral ...chronic inflammation of the ocular surface. The diagnosis is generally confirmed by the finding at the ocular examination of conjunctival hyperemia, papillary hypertrophy in the tarsal conjunctiva, giant papillae, papillae in the limbus region.
Aim of this review is to provide an updated overview on the disease focused on clinical grading system, searching papers published in the last decade on VKC in scientific databases.
Currently there are no standardized criteria for diagnosis of VKC and there is no uniformity to define disease severity, which makes difficult to diagnose and treat the disease.
Given the wide overlap of the symptoms of VKC with the allergic conjunctivitis, criteria of probable, possible or improbable diagnosis are needed, providing pediatricians with parameters useful for deciding whether to drive the patient to the ophthalmologist for diagnostic confirmation.
Although potential links between oxytocin (OT), vasopressin (AVP), and social cognition are well-grounded theoretically, most studies have included all male samples, and few have demonstrated ...consistent effects of either neuropeptide on mentalizing (i.e. understanding the mental states of others). To understand the potential of either neuropeptide as a pharmacological treatment for individuals with impairments in social cognition, it is important to demonstrate the beneficial effects of OT and AVP on mentalizing in healthy individuals.
In the present randomized, double-blind, placebo-controlled study (
= 186) of healthy individuals, we examined the effects of OT and AVP administration on behavioral responses and neural activity in response to a mentalizing task.
Relative to placebo, neither drug showed an effect on task reaction time or accuracy, nor on whole-brain neural activation or functional connectivity observed within brain networks associated with mentalizing. Exploratory analyses included several variables previously shown to moderate OT's effects on social processes (e.g., self-reported empathy, alexithymia) but resulted in no significant interaction effects.
Results add to a growing literature demonstrating that intranasal administration of OT and AVP may have a more limited effect on social cognition, at both the behavioral and neural level, than initially assumed. Randomized controlled trial registrations: ClinicalTrials.gov; NCT02393443; NCT02393456; NCT02394054.
Abstract Background and aims Previous meta-analyses of interventional trials with vitamin E provided negative results but it remains unclear if this vitamin has some influence on cardiovascular ...events when supplemented alone. The aim of this study was to compare the effect of vitamin E alone or in combination with other antioxidants on myocardial infarction. Methods and results Pubmed, ISI Web of Science, SCOPUS and Cochrane database were searched without language restrictions. We investigated randomized clinical trials studying the effect of vitamin E supplementation on myocardial infarction. Sixteen randomized controlled trials of vitamin E treatment were analyzed in this meta-analysis. The dose range for vitamin E was 33–800 IU. Follow-up ranged from 0.5 to 9.4 years. Compared to controls, vitamin E given alone significantly decreased myocardial infarction (3.0% vs 3.4%) (random effects R.R.: 0.82; 95% C.I., 0.70–0.96; p = 0.01). This effect was driven by reduction of fatal myocardial infarction (random effects R.R.: 0.84; 95% C.I., 0.73–0.96; p = 0.01). Conclusions When supplemented alone, vitamin E reduces myocardial infarction in interventional trials while it appears ineffective when associated with other antioxidants.
Designing persuasive content is challenging, in part because people can be poor predictors of their actions. Medial prefrontal cortex (MPFC) activation during message exposure reliably predicts ...downstream behavior, but past work has been largely atheoretical. We replicated past results on this relationship and tested two additional framing effects known to alter message receptivity. First, we examined gain- vs. loss-framed reasons for a health behavior (sunscreen use). Consistent with predictions from prospect theory, we observed greater MPFC activity to gain- vs. loss-framed messages, and this activity was associated with behavior. This relationship was stronger for those who were not previously sunscreen users. Second, building on theories of action planning, we compared neural activity during messages regarding how vs. why to enact the behavior. We observed rostral inferior parietal lobule and posterior inferior frontal gyrus activity during action planning ("how" messages), and this activity was associated with behavior; this is in contrast to the relationship between MPFC activity during the "why" (i.e., gain and loss) messages and behavior. These results reinforce that persuasion occurs in part via self-value integration-seeing value and incorporating persuasive messages into one's self-concept-and extend this work to demonstrate how message framing and action planning may influence this process.
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