Lifeboat Foundation

The ability to modulate neural activity in specific brain circuits remotely and systematically could revolutionize studies of brain function and treatments of brain disorders. Sound waves of high frequencies (ultrasound) have shown promise in this respect, combining the ability to modulate neuronal activity with sharp spatial focus. Here, we show that the approach can have potent effects on choice behavior. Brief, low-intensity ultrasound pulses delivered noninvasively into specific brain regions of macaque monkeys influenced their decisions regarding which target to choose. The effects were substantial, leading to around a 2:1 bias in choices compared to the default balanced proportion. The effect presence and polarity was controlled by the specific target region. These results represent a critical step towards the ability to influence choice behavior noninvasively, enabling systematic investigations and treatments of brain circuits underlying disorders of choice.

Noninvasive and reversible modulation of neuronal activity in specific brain circuits may allow us to diagnose and treat brain disorders in, targeted ways. Low-intensity ultrasound, applied to the brain noninvasively, can be used to modulate neural activity with spatial specificity superior to other noninvasive methods such as transcranial electrical or magnetic stimulation (1–5). The neuromodulatory potential of ultrasound has been highlighted in studies that targeted peri-motor regions of anesthetized rodents or rabbits. Brief, low-intensity stimuli lead to observable movements of the limbs or other body parts (6–13).

However, the enthusiasm about the neuromodulatory potential of ultrasound has recently been dampened by studies that called these effects into question (14, 15). In addition, such overt effects have not been observed in large mammals including humans. Only small changes in neural signals (16–23) or small changes in reaction time or other metrics (24–26) have been found. Yet, to make it truly useful, the approach would ideally provide neuromodulatory effects that are strong enough to manifest in behavior. For example, if clinicians are to determine which brain circuits drive a patient’s craving for an addictive drug, the neuromodulatory effects on a particular neural circuit should be potent enough to yield measurable changes in the subject’s choice behavior, i.e., whether the subject decides to use the drug or not.

Revealing yet another super-power in the skillful squid, scientists have discovered that squid massively edit their own genetic instructions not only within the nucleus of their neurons, but also within the axon — the long, slender neural projections that transmit electrical impulses to other neurons. This is the first time that edits to genetic information have been observed outside of the nucleus of an animal cell.

The study, led by Isabel C. Vallecillo-Viejo and Joshua Rosenthal at the Marine Biological Laboratory (MBL), Woods Hole, is published this week in Nucleic Acids Research.

The collision of two intense light beams may produce detectable signatures of dark matter particles called axions.

Axions—hypothetical particles that are much lighter than electrons—could hold the key to important physics puzzles, from the matter–antimatter asymmetry to the nature of dark matter. So far, the strongest constraints on their properties, such as their mass and how they couple to photons, come from astrophysical measurements that look for axions produced by photons interacting with magnetic fields inside the Sun. Now, Konstantin Beyer at the University of Oxford, UK, and colleagues propose a lab-scale experiment based on colliding intense laser beams. The researchers say that, for an important range of axion masses, their approach would be as sensitive as astrophysical searches but much less dependent on hard-to-test models of astrophysical axion-generation processes.

The team’s scheme is a variation of the “light-shining-through-a-wall” (LSW) method of axion detection. In LSW, axions created by a laser beam propagating in a magnetic field would be detected after passing through a wall that shields the detector from the laser photons. The team’s new scheme uses two laser beams, whose collision may produce axions through a light–light scattering process. After passing through the wall, the axions would be converted into detectable photons by a magnetic field.

String theory provides a microscopic description of the entropy of certain theoretical black holes—an important step toward understanding black hole thermodynamics.

In the 1970’s, theorists determined that black holes have entropy [1], a remarkable finding that points at analogies between these spacetime singularities and systems of particles, such as classical gases. The crucial proof was provided by Stephen Hawking, who demonstrated, using a quantum-mechanical framework, that black holes radiate as if they were black bodies with a specific temperature [2]. The analogy was completed by extending all four laws of thermodynamics to black holes [3]. In thermodynamics, entropy is an important bridge between the macroscopic and the microscopic world: In a gas, for instance, entropy relates macroscopic heat transfer to the number of available microscopic states of the gas molecules. Providing a similar microscopic explanation of black hole entropy is an important test for theories that aim to unify gravity and quantum mechanics.

A visual cortical prosthesis (VCP) has long been proposed as a strategy for restoring useful vision to the blind, under the assumption that visual percepts of small spots of light produced with electrical stimulation of visual cortex (phosphenes) will combine into coherent percepts of visual forms, like pixels on a video screen. We tested an alternative strategy in which shapes were traced on the surface of visual cortex by stimulating electrodes in dynamic sequence. In both sighted and blind participants, dynamic stimulation enabled accurate recognition of letter shapes predicted by the brain’s spatial map of the visual world. Forms were presented and recognized rapidly by blind participants, up to 86 forms per minute. These findings demonstrate that a brain prosthetic can produce coherent percepts of visual forms.

Circa 2019 The world’s largest lighting company thinks it has just the thing for people fed up with wobbly WiFi signals that cut out, slow down or don’t work at all in cafes, parks, airports and other public places where the technology can be deeply unreliable.

Signify—the former Philips Lighting—has for years been developing an alternative broadband technology that transmits the Internet using light waves from commercial LED light fittings rather than the radio waves of WiFi. Now, in a recently announced deal it’s teaming up with one of the world’s largest telecommunication firms, Vodafone, in a bid to turn the technology into a daily reality.

The light at the end of the wifi tunnel?

Israeli entrepreneurs and researchers have introduced facemask and face shield inventions we want to tell you about.

Let’s begin with an update on that first article highlighting washable masks from Sonovia and from Argaman. Each uses its own proprietary technology to embed microbe-killing metallic particles into textiles.

Continue reading “7 Israeli mask and face shield solutions for coronavirus” »

Special relativity prevents any object with mass travelling at the speed of light, and the principle of causality – the notion that the cause comes before the effect – is used to rule out the possibility of superluminal (faster-than-light) travel by light itself. However, a pulse of light can have more than one speed because it is made up of light of different wavelengths. The individual waves travel at their own phase velocity, while the pulse itself travels with the group velocity. In a vacuum all the phase velocities and the group velocity are the same. In a dispersive medium, however, they are different because the refractive index is a function of wavelength, which means that the different wavelengths travel at different speeds. Wang and colleagues report evidence for a negative group velocity of −310 c, where c (=300 million metres per second) is the speed of light in vacuum.

Their experimental set-up is remarkably similar to that used to slow light to a speed of just 17 metres per second last year. It relies on using two lasers and a magnetic field to prepare a gas of caesium atoms in an excited state. This state exhibits strong amplification or gain at two wavelengths, and highly anomalous dispersion – that is, the refractive index changes rapidly with wavelength – in the region between these two peaks.

Wang and colleagues begin by using a third continuous-wave laser to confirm that there are two peaks in the gain spectrum and that the refractive index does indeed change rapidly with wavelength in between. Next they send a 3.7-microsecond long laser pulse into the caesium cell, which is 6 centimetres long, and show that, at the correct wavelength, it emerges from the cell 62 nanoseconds sooner than would be expected if it had travelled at the speed of light. 62 nanoseconds might not sound like much, but since it should only take 0.2 nanoseconds for the pulse to pass through the cell, this means that the pulse has been travelling at 310 times the speed of light. Moreover, unlike previous superluminal experiments, the input and output pulse shapes are essentially the same.

Schizophrenia is a devastating psychiatric disorder characterized by positive, negative and cognitive symptoms. While aberrant dopamine system function is typically associated with the positive symptoms of the disease, it is thought that this is secondary to pathology in afferent regions. Indeed, schizophrenia patients show dysregulated activity in the hippocampus and prefrontal cortex, two regions known to regulate dopamine neuron activity. These deficits in hippocampal and prefrontal cortical function are thought to result, in part, from reductions in inhibitory interneuron function in these brain regions. Therefore, it has been hypothesized that restoring interneuron function in the hippocampus and/or prefrontal cortex may be an effective treatment strategy for schizophrenia. In this article, we will discuss the evidence for interneuron pathology in schizophrenia and review recent advances in our understanding of interneuron development. Finally, we will explore how these advances have allowed us to test the therapeutic value of interneuron transplants in multiple preclinical models of schizophrenia.

Schizophrenia is devastating psychiatric disorder that affects approximately 1% of the population¹. Positive symptoms, such as paranoia, grandiosity, delusions, and hallucinations, are often the most striking features of the disorder; however, schizophrenia patients also display characteristic negative and cognitive symptoms, which can be severely debilitating. Negative symptoms, such as blunted affect, emotional withdrawal, and social avoidance and cognitive symptoms, including disruptions in working memory, attentional deficits, disorganized thought, and cognitive inflexibility, can negatively influence social and occupational functioning and diminish quality of life^2–4. Currently prescribed antipsychotic medications, which act as antagonists at the dopamine D2 receptor⁵, have been somewhat effective in treating the positive symptoms of schizophrenia⁶.