Measuring away an attentional confound?

A recent fMRI study by Webb et al. (Cortical networks involved in visual awareness independent of visual attention, Proc Natl Acad Sci U S A 2016;113:13923–28) proposes a new method for finding the neural correlates of awareness by matching atten- tion across awareness conditions. The experimental design, however, seems at odds with known features of attention. We highlight logical and methodological points that are critical when trying to disentangle attention and awareness

Lasing mode pattern of a quantum cascade photonic crystal surface-emitting microcavity laser

The identification of the lasing mode within a quantum cascade photonic crystal microcavity laser emitting at λ ~8 µm is presented. The symmetry of the lasing mode is determined by the position of nodal lines within micro-bolometer camera measurements of its polarized spatial distribution. Full three-dimensional finite-difference time-domain simulations are also performed, and the resulting vertically emitted radiation field pattern is seen to follow the experimental results closely

Event related potentials elicited by violations of auditory regularities in patients with impaired consciousness.

International audienceImproving our ability to detect conscious processing in non communicating patients remains a major goal of clinical cognitive neurosciences. In this perspective, several functional brain imaging tools are currently under development. Bedside cognitive event-related potentials (ERPs) derived from the EEG signal are a good candidate to explore consciousness in these patients because: (1) they have an optimal time resolution within the millisecond range able to monitor the stream of consciousness, (2) they are fully non-invasive and relatively cheap, (3) they can be recorded continuously on dedicated individual systems to monitor consciousness and to communicate with patients, (4) and they can be used to enrich patients' autonomy through brain-computer interfaces. We recently designed an original auditory rule extraction ERP test that evaluates cerebral responses to violations of temporal regularities that are either local in time or global across several seconds. Local violations led to an early response in auditory cortex, independent of attention or the presence of a concurrent visual task, while global violations led to a late and spatially distributed response that was only present when subjects were attentive and aware of the violations. In the present work, we report the results of this test in 65 successive recordings obtained at bedside from 49 non-communicating patients affected with various acute or chronic neurological disorders. At the individual level, we confirm the high specificity of the 'global effect': only conscious patients presented this proposed neural signature of conscious processing. Here, we also describe in details the respective neural responses elicited by violations of local and global auditory regularities, and we report two additional ERP effects related to stimuli expectancy and to task learning, and we discuss their relations to consciousness

Quantum Cascade Surface-Emitting Photonic Crystal Laser

We combine photonic and electronic band structure engineering to create a surface-emitting quantum cascade microcavity laser. A high-index contrast two-dimensional photonic crystal is used to form a micro-resonator that simultaneously provides feedback for laser action and diffracts light vertically from the surface of the semiconductor surface. A top metallic contact allows electrical current injection and provides vertical optical confinement through a bound surface plasmon wave. The miniaturization and tailorable emission properties of this design are potentially important for sensing applications, while electrical pumping can allow new studies of photonic crystal and surface plasmon structures in nonlinear and near-field optics

Quantum cascade photonic-crystal microlasers

We describe the realization of Quantum Cascade photonic-crystal microlasers. Photonic and electronic bandstructure engineering are combined to create a novel Quantum Cascade microcavity laser source. A high-index contrast two-dimensional photonic crystal forms a micro-resonator that provides feedback for laser action and diffracts light vertically from the surface of the semiconductor chip. A top metallic contact is used to form both a conductive path for current injection as well as to provide vertical optical confinement to the active region through a bound surface plasmon state at the metal-semiconductor interface. The device is miniaturized compared to standard Quantum Cascade technology, and the emission properties can in principle be engineered by design of the photonic crystal lattice. The combination of size reduction, vertical emission, and lithographic tailorability of the emission properties enabled by the use of a high-index contrast photonic crystal resonant cavity makes possible a number of active sensing applications in the mid- and far-infrared. In addition, the use of electrical pumping in these devices opens up another dimension of control for fundamental studies of photonic crystal and surface plasmon structures in linear, non-linear, and near-field optics

Quantum cascade photonic-crystal microlasers

We describe the realization of Quantum Cascade photonic-crystal microlasers. Photonic and electronic bandstructure engineering are combined to create a novel Quantum Cascade microcavity laser source. A high-index contrast two-dimensional photonic crystal forms a micro-resonator that provides feedback for laser action and diffracts light vertically from the surface of the semiconductor chip. A top metallic contact is used to form both a conductive path for current injection as well as to provide vertical optical confinement to the active region through a bound surface plasmon state at the metal-semiconductor interface. The device is miniaturized compared to standard Quantum Cascade technology, and the emission properties can in principle be engineered by design of the photonic crystal lattice. The combination of size reduction, vertical emission, and lithographic tailorability of the emission properties enabled by the use of a high-index contrast photonic crystal resonant cavity makes possible a number of active sensing applications in the mid- and far-infrared. In addition, the use of electrical pumping in these devices opens up another dimension of control for fundamental studies of photonic crystal and surface plasmon structures in linear, non-linear, and near-field optics

An Informal Internet Survey on the Current State of Consciousness Science

The scientific study of consciousness emerged as an organized field of research only a few decades ago. As empirical results have begun to enhance our understanding of consciousness, it is important to find out whether other factors, such as funding for consciousness research and status of consciousness scientists, provide a suitable environment for the field to grow and develop sustainably. We conducted an online survey on people's views regarding various aspects of the scientific study of consciousness as a field of research. 249 participants completed the survey, among which 80% were in academia, and around 40% were experts in consciousness research. Topics covered include the progress made by the field, funding for consciousness research, job opportunities for consciousness researchers, and the scientific rigor of the work done by researchers in the field. The majority of respondents (78%) indicated that scientific research on consciousness has been making progress. However, most participants perceived obtaining funding and getting a job in the field of consciousness research as more difficult than in other subfields of neuroscience. Overall, work done in consciousness research was perceived to be less rigorous than other neuroscience subfields, but this perceived lack of rigor was not related to the perceived difficulty in finding jobs and obtaining funding. Lastly, we found that, overall, the global workspace theory was perceived to be the most promising (around 28%), while most non-expert researchers (around 22% of non-experts) found the integrated information theory (IIT) most promising. We believe the survey results provide an interesting picture of current opinions from scientists and researchers about the progresses made and the challenges faced by consciousness research as an independent field. They will inspire collective reflection on the future directions regarding funding and job opportunities for the field