Pattern-Induced Visual Discomfort and Anxiety in Migraineurs: Their Relationship and the Effect of Colour

In migraineurs, coloured lenses were found to reduce the visual stress caused by an aversive pattern known to trigger migraines by 70%, but do such patterns also produce a low-level anxiety/fear response? Is this response lessened by colour? We sought to investigate this in a study comprising a broad screening component followed by a dot-probe experiment to elicit attentional biases (AB) to aversive patterns. Undergraduate psychology students completed headache and visual discomfort (VD) questionnaires (N = 358), thereby forming a subject pool from which 13 migraineurs with high visual discomfort and 13 no-headache controls with low visual discomfort, matched on age and sex, completed a dot-probe experiment. Paired stimuli were presented for 500 ms: aversive achromatic 3 cpd square wave gratings vs control, scrambled patterns. These conditions were repeated using the colour that was most comfortable for each participant. VD was greater in the more severe headache groups. On all measures, the migraineurs were more anxious than the controls, and a positive relationship was found between VD and trait anxiety. The 3 cpd gratings elicited an aversive AB in the migraine group which was somewhat reduced by the use of colour, and this was not seen in the controls. The results suggest a new role for colour in reducing visual stress via anxiety/fear reduction.

Study of Allowable Interlaminar Normal Stress Based on the Time–Temperature Equivalence Principle in Automated Fiber Placement Process

Automatic fiber placement (AFP) is a type of labor-saving automatic technology for forming composite materials that are widely used in aviation and other fields. In this process, concave surface delamination is a common defect, as existing research on the conditions for this defect to occur is insufficient. To predict the occurrence of this defect, the concept of allowable interlaminar normal stress is proposed to define its occurrence conditions, and based on this concept, probe tests are carried out using the principle of time–temperature equivalence. Through the laying speed/allowable normal stress curve measured in the probe experiment, the physical meaning of allowable normal stress is discussed. At the same time, the measured curve is quantitatively analyzed, combined with viscoelastic theory and the molecular diffusion reptation model, and the dominating effect in the formation of a metal/prepreg layer and prepreg/prepreg layer is determined. Finally, the experimental data are used to guide the parameter selection in an automatic placement engineering case and prove its correctness.

Neuroadaptive Changes in 5-HT1A Autoreceptor Sensitivity Following High-Dose MDMA Treatment

<p>Rationale: There is evidence that the serotonin (5-HT) deficits and related cognitive and mood impairments caused by +/-3,4- methylenedioxymethamphetamine (MDMA) may be mediated by neuroadaptations of the 5-HT1A autoreceptor. Objectives: The increase in sensitivity of the 5-HT1A autoreceptor caused by highdose, repeated MDMA treatment was assessed neurochemically, by measuring 5- HTP accumulation, and physiologically, via changes in body temperature. Methods: Experiment 1 confirmed the effects of 8-hydroxy-2-(di-npropylamino) tetralin (8-OH-DPAT) (0, 0.025, 0.05, 0.1 mg/kg s.c.) on 5- hydroxytryptophan (5-HTP) accumulation following 3-hydroxybenzylhydrazine dihydrochloride (NSD-1015) administration as a valid measure of 5-HT synthesis and hence 5-HT1A autoreceptor sensitivity in rats. Experiment 2 performed these procedures in additional animals, with half receiving MDMA (4x 10 mg/kg i.p. at 2 hour intervals) two weeks before testing. Body temperature changes due to the 8-OH-DPAT hypothermic response were tested using a rectal probe. Experiment 2b repeated the procedures in additional groups with lower doses of 8-OH-DPAT (0.0125 and 0.00625 mg/kg s.c.). Results: No significant changes in 5-HTP accumulation levels or changes in the hypothermic response to 8-OH-DPAT were found between MDMA pretreated rats and controls in Experiments 2 and 2b. Moreover, there was no substantial evidence of expected 5-HT deficits due to high-dose MDMA treatment. Conclusion: The results do not indicate an increase in sensitivity of the 5-HT1A autoreceptor, and hence the original hypothesis is not supported. However, there were a number of methodological issues, as indicated by the lack of MDMAinduced 5-HT deficits, which prevent a firm conclusion from being drawn. Future research is outlined to overcome these issues.</p>

Neuroadaptive Changes in 5-HT1A Autoreceptor Sensitivity Following High-Dose MDMA Treatment

<p>Rationale: There is evidence that the serotonin (5-HT) deficits and related cognitive and mood impairments caused by +/-3,4- methylenedioxymethamphetamine (MDMA) may be mediated by neuroadaptations of the 5-HT1A autoreceptor. Objectives: The increase in sensitivity of the 5-HT1A autoreceptor caused by highdose, repeated MDMA treatment was assessed neurochemically, by measuring 5- HTP accumulation, and physiologically, via changes in body temperature. Methods: Experiment 1 confirmed the effects of 8-hydroxy-2-(di-npropylamino) tetralin (8-OH-DPAT) (0, 0.025, 0.05, 0.1 mg/kg s.c.) on 5- hydroxytryptophan (5-HTP) accumulation following 3-hydroxybenzylhydrazine dihydrochloride (NSD-1015) administration as a valid measure of 5-HT synthesis and hence 5-HT1A autoreceptor sensitivity in rats. Experiment 2 performed these procedures in additional animals, with half receiving MDMA (4x 10 mg/kg i.p. at 2 hour intervals) two weeks before testing. Body temperature changes due to the 8-OH-DPAT hypothermic response were tested using a rectal probe. Experiment 2b repeated the procedures in additional groups with lower doses of 8-OH-DPAT (0.0125 and 0.00625 mg/kg s.c.). Results: No significant changes in 5-HTP accumulation levels or changes in the hypothermic response to 8-OH-DPAT were found between MDMA pretreated rats and controls in Experiments 2 and 2b. Moreover, there was no substantial evidence of expected 5-HT deficits due to high-dose MDMA treatment. Conclusion: The results do not indicate an increase in sensitivity of the 5-HT1A autoreceptor, and hence the original hypothesis is not supported. However, there were a number of methodological issues, as indicated by the lack of MDMAinduced 5-HT deficits, which prevent a firm conclusion from being drawn. Future research is outlined to overcome these issues.</p>

Tracing orbital images on ultrafast time scales

Frontier orbitals determine fundamental molecular properties such as chemical reactivities. Although electron distributions of occupied orbitals can be imaged in momentum space by photoemission tomography, it has so far been impossible to follow the momentum-space dynamics of a molecular orbital in time, for example through an excitation or a chemical reaction. Here, we combined time-resolved photoemission using high laser harmonics and a momentum microscope to establish a tomographic, femtosecond pump-probe experiment of unoccupied molecular orbitals. We measured the full momentum-space distribution of transiently excited electrons, connecting their excited-state dynamics to real-space excitation pathways. Because in molecules this distribution is closely linked to orbital shapes, our experiment may in the future offer the possibility to observe ultrafast electron motion in time and space.

Faster chiral versus collinear magnetic order recovery after optical excitation revealed by femtosecond XUV scattering

While chiral spin structures stabilized by Dzyaloshinskii-Moriya interaction (DMI) are candidates as novel information carriers, their dynamics on the fs-ps timescale is little known. Since with the bulk Heisenberg exchange and the interfacial DMI two distinct exchange mechanisms are at play, the ultrafast dynamics of the chiral order needs to be ascertained and compared to the dynamics of the conventional collinear order. Using an XUV free-electron laser we determine the fs-ps temporal evolution of the chiral order in domain walls in a magnetic thin film sample by an IR pump - X-ray magnetic scattering probe experiment. Upon demagnetization we observe that the dichroic (CL-CR) signal connected with the chiral order correlator mzmx in the domain walls recovers significantly faster than the (CL + CR) sum signal representing the average collinear domain magnetization mz2 + mx2. We explore possible explanations based on spin structure dynamics and reduced transversal magnetization fluctuations inside the domain walls and find that the latter can explain the experimental data leading to different dynamics for collinear magnetic order and chiral magnetic order.

Superconducting optical response of photodoped Mott insulators

Ultrafast laser pulses can redistribute charges in Mott insulators on extremely short time scales, leading to the fast generation of photocarriers. It has recently been demonstrated that these photocarriers can form a novel [Formula: see text]-paired condensate at low temperatures, featuring a staggered superconducting pairing field. In this conference paper, we discuss the origin of the [Formula: see text]-paired hidden phase and its optical response, which may be detected in a pump-probe experiment. The hidden phase may be relevant for possible light-induced superconductivity in Mott insulators.

The self-face captures attention without consciousness: evidence from the N2pc ERP component analysis

It is well established that stimuli representing or associated with ourselves, like our own name or an image of our own face, benefit from preferential processing. However, two key questions concerning the self-prioritization mechanism remain to be addressed. First, does it operate in an automatic manner during the early processing, or rather in a more controlled fashion at later processing stages? Second, is it specific to the self-related stimuli, or can it be activated also by other stimuli that are familiar or salient? We conducted a dot-probe experiment to investigate the mechanism behind attentional prioritization of the selfface image and to tackle both questions. The former, by employing a backwards masking procedure to isolate the early and preconscious processing stages. The latter, by investigating whether a face that becomes visually familiar due to repeated presentations is able to capture attention in a similar manner as the self-face. Analysis of the N2pc ERP component revealed that the self-face image automatically captures attention, both when processed consciously and unconsciously. In contrast, the visually familiar face did not attract attention, neither in the conscious, nor in the unconscious condition. We conclude that the selfprioritization mechanism is early and automatic, and is not triggered by a mere visual familiarity. More generally, our results provide further evidence for efficient unconscious processing of faces, and for a dissociation between attention and consciousness.