Relating alpha power modulations to competing visuospatial attention theories

Visuospatial attention theories often propose hemispheric asymmetries underlying the control of attention. In general support of these theories, previous EEG/MEG studies have shown that spatial attention is associated with hemispheric modulation of posterior alpha power (gating by inhibition). However, since measures of alpha power are typically expressed as lateralization scores, or collapsed across left and right attention shifts, the individual hemispheric contribution to the attentional control mechanism remains unclear. This is, however, the most crucial and decisive aspect in which the currently competing attention theories continue to disagree. To resolve this long-standing conflict, we derived predictions regarding alpha power modulations from Heilman's hemispatial theory and Kinsbourne's interhemispheric competition theory and tested them empirically in an EEG experiment. We used an attention paradigm capable of isolating alpha power modulation in two attentional states, namely attentional bias in a neutral cue condition and spatial orienting following directional cues. Differential alpha modulations were found for both hemispheres across conditions. When anticipating peripheral visual targets without preceding directional cues (neutral condition), posterior alpha power in the left hemisphere was generally lower and more strongly modulated than in the right hemisphere, in line with the interhemispheric competition theory. Intriguingly, however, while alpha power in the right hemisphere was modulated by both, cue-directed leftward and rightward attention shifts, the left hemisphere only showed modulations by rightward shifts of spatial attention, in line with the hemispatial theory. This suggests that the two theories may not be mutually exclusive, but rather apply to different attentional states

Left parietal tACS at alpha frequency induces a shift of visuospatial attention

Background Voluntary shifts of visuospatial attention are associated with a lateralization of parieto-occipital alpha power (7-13Hz), i.e. higher power in the hemisphere ipsilateral and lower power contralateral to the locus of attention. Recent noninvasive neuromodulation studies demonstrated that alpha power can be experimentally increased using transcranial alternating current stimulation (tACS). Objective/Hypothesis We hypothesized that tACS at alpha frequency over the left parietal cortex induces shifts of attention to the left hemifield. However, spatial attention shifts not only occur voluntarily (endogenous/ top-down), but also stimulus-driven (exogenous/ bottom-up). To study the task-specificity of the potential effects of tACS on attentional processes, we administered three conceptually different spatial attention tasks. Methods 36 healthy volunteers were recruited from an academic environment. In two separate sessions, we applied either high-density tACS at 10Hz, or sham tACS, for 35–40 minutes to their left parietal cortex. We systematically compared performance on endogenous attention, exogenous attention, and stimulus detection tasks. Results In the endogenous attention task, a greater leftward bias in reaction times was induced during left parietal 10Hz tACS as compared to sham. There were no stimulation effects in either the exogenous attention or the stimulus detection task. Conclusion The study demonstrates that high-density tACS at 10Hz can be used to modulate visuospatial attention performance. The tACS effect is task-specific, indicating that not all forms of attention are equally susceptible to the stimulation

Single-chip CMOS optical microspectrometer

Numerous applications, e.g., systems for chemical analysis by optical absorption and emission line characterization, will benefit from the availability of low-cost single-chip spectrometers. A single-chip CMOS optical microspectrometer containing an array of 16 addressable Fabry–Perot etalons (each one with different resonance cavity length), photodetectors and circuits for read-out, multiplexing and driving a serial bus interface has been fabricated. The result is a chip that can operate using only four external connections (including Vdd and Vss). covering the visible spectral range of the spectrum with FWHM = 18 nm. Frequency output and serial bus interface allow easy multi-sensor, multi-chip interfacing using a microcontroller or a personal computer. Power consumption is 1250 µW for a clock frequency of 1 MHzFundação para a Ciência e a Tecnologia (FCT

Stability of additive-free water-in-oil emulsions

We calculate ion distributions near a planar oil-water interface within non-linear Poisson-Boltzmann theory, taking into account the Born self-energy of the ions in the two media. For unequal self-energies of cations and anions, a spontaneous charge separation is found such that the water and oil phase become oppositely charged, in slabs with a typical thickness of the Debye screening length in the two media. From the analytical solutions, the corresponding interfacial charge density and the contribution to the interfacial tension is derived, together with an estimate for the Yukawa-potential between two spherical water droplets in oil. The parameter regime is explored where the plasma coupling parameter exceeds the crystallization threshold, i.e. where the droplets are expected to form crystalline structures due to a strong Yukawa repulsion, as recently observed experimentally. Extensions of the theory that we discuss briefly include numerical calculations on spherical water droplets in oil, and analytical calculations of the linear PB-equation for a finite oil-water interfacial width.Comment: 9 pages, 4 figures, accepted by JPCM for proceedings of LMC

Online Acceptance and Commitment Therapy (ACT) interventions for chronic pain:A systematic literature review

Background We systematically reviewed all literature concerning online Acceptance and Commitment Therapy (ACT) interventions for chronic pain to evaluate their (1) ACT content, (2) design characteristics, (3) design rationales, and (4) adherence. Material and methods: A systematic search was performed on July 9th, 2020 in; PubMed, PsycINFO, CINAHL, and Web of Science. Search terms related to: Acceptance and Commitment Therapy, chronic pain, and eHealth. Extracted data concerned ACT content, design characteristics, adherence, and design rationales. Results 20 articles, in which 14 interventions were described, met all inclusion criteria. Adherence and design rationales were described to a limited extent in the included studies. In total, the majority provided an overview of the included ACT processes. In 10 articles it was described that the intervention was delivered via a dedicated website (n = 10), which was sometimes combined with an app (n = 3). Guidance was included in most studies (n = 19). Studies including RCT's (n = 8) reported online ACT interventions to be effective. Conclusion Online ACT interventions for chronic pain have been shown to be effective and have generally been constructed in line with ACT theory. However, the majority of studies does not provide information about the choices to optimize the fit between task, technology, and user. Considerations behind the choices for intervention features as well as design rationales could help to optimize future online ACT interventions. Additionally, consistent attention should be paid to measurement and operationalization of adherence, since this is a crucial link between content, design and effectiveness

Optical microspectrometer using a micro-instrumentation platform

MEMS are usually designed for measuring one parameter and on-chip co-integration of sensor (microstructure) and readout circuits is often pursued. In a multi-parameter measurement system, yield considerations and fabrication compatibility problems favor micro-instruments based on active Si-MCM techniques. The generic device is based on a stacked structure with a universally applicable active silicon MCM platform that contains all the infrastructural functions of a measurement system. Customizing the microsystem requires flip-chip attach of sensor dies and a commercially available microcontroller die, which is subsequently programmed for the intended application. The micro-instrument features a data pre processing capability to provide high-level data (e.g. spectral information rather than raw sensor data) and to communicate with a host processor intelligently.STW - project DEL 55.3733.TU Delft, Fundação para a Ciência e Tecnologia (FCT) - Program Praxis XXI-BD/5181/95

A single-chip CMOS optical microspectrometer with light-to-frequency converter and bus interface

A single-chip CMOS optical microspectrometer containing an array of 16 addressable Fabry–Perot etalons (each one with a different resonance cavity length), photodetectors, and circuits for readout, multiplexing, and driving a serial bus interface has been fabricated in a standard 1.6 um CMOS technology (chiparea 3.9x4.2 mm2). The result is a chip that can operate using only four external connections (including and ) covering the optical range of 380–500 nm with full-width half-maximum (FWHM) = 18 nm. Frequency output and serial bus interface allow easy multisensor and multichip interfacing using a microcontroller or a personal computer. Power consumption is 1250 W for a clock frequency of 1 MHz.Fundação para a Ciência e a Tecnologia (FCT

Actions of metformin and statins on lipid and glucose metabolism and possible benefit of combination therapy

Patients with diabetes type 2 have an increased risk for cardiovascular disease and commonly use combination therapy consisting of the anti-diabetic drug metformin and a cholesterol-lowering statin. However, both drugs act on glucose and lipid metabolism which could lead to adverse effects when used in combination as compared to monotherapy. In this review, the proposed molecular mechanisms of action of statin and metformin therapy in patients with diabetes and dyslipidemia are critically assessed, and a hypothesis for mechanisms underlying interactions between these drugs in combination therapy is developed

Symptoms of pre-treatment anxiety are associated with the development of chronic peripheral neuropathy among colorectal cancer patients

Purpose Identifying potentially modifiable predictors of chronic (chemotherapy-induced) peripheral neuropathy (PN) is important, especially in light of the limited treatment options. We aimed to examine pre-treatment anxiety and depressive symptoms as predictors of chronic PN symptom severity in colorectal cancer (CRC) patients up to two years after diagnosis. Methods Newly diagnosed CRC patients from four Dutch hospitals were eligible for participation. Patients (N=336) completed a questionnaire on anxiety and depressive symptoms (HADS) and sensory (SPN) and motor peripheral neuropathy (MPN) (EORTC QLQ-CIPN20) before initial treatment (baseline) and one and two years after diagnosis. Patients were included in the analyses if they either developed some level of SPN or MPN symptoms, or experienced a worsening of pre-treatment SPN or MPN symptoms. Results At one-year follow-up, 115 patients (34%) reported SPN symptoms and 134 patients (40%) reported MPN symptoms. Of these patients, SPN and MPN symptoms had not returned to baseline level at two-year follow-up in, respectively, 51% and 54% of patients. In multivariable regression analyses, neither pre-treatment anxiety symptoms nor pre-treatment depressive symptoms were associated with SPN or MPN symptom severity at one-year follow-up. At two-year follow-up, pre-treatment anxiety symptoms (β=0.44, p=0.01), but not depressive symptoms, were associated with SPN symptom severity. Conclusions Pre-treatment anxiety symptoms, but not depressive symptoms, were associated with SPN symptom severity two years after diagnosis. Future studies are needed that assess whether interventions targeted to reduce anxiety before and during treatment can reduce chronic PN severity or even prevent the persistence of PN