Lifeboat Foundation

The gastrointestinal hormones ghrelin and glucagon-like peptide-1 (GLP-1) have opposite secretion patterns, as well as opposite effects on metabolism and food intake. Beyond their role in energy homeostasis, gastrointestinal hormones have also been suggested to modulate the reward system. However, the potential of ghrelin and GLP-1 to modulate reward responses in humans has not been systematically reviewed before. To evaluate the convergence of published results, we first conduct a multi-level kernel density meta-analysis of studies reporting a positive association of ghrelin (N_comb = 353, 18 contrasts) and a negative association of GLP-1 (N_comb = 258, 12 contrasts) and reward responses measured using task functional magnetic resonance imaging (fMRI). Second, we complement the meta-analysis using a systematic literature review, focusing on distinct reward phases and applications in clinical populations that may account for variability across studies. In line with preclinical research, we find that ghrelin increases reward responses across studies in key nodes of the motivational circuit, such as the nucleus accumbens, pallidum, putamen, substantia nigra, ventral tegmental area, and the dorsal mid insula. In contrast, for GLP-1, we did not find sufficient convergence in support of reduced reward responses. Instead, our systematic review identifies potential differences of GLP-1 on anticipatory versus consummatory reward responses. Based on a systematic synthesis of available findings, we conclude that there is considerable support for the neuromodulatory potential of gut-based circulating peptides on reward responses. To unlock their potential for clinical applications, it may be useful for future studies to move beyond anticipated rewards to cover other reward facets.

Early critiques pointed out that proving a network was near the critical point required improved statistical tests. The field responded constructively, and this type of objection is rarely heard these days. More recently, some work has shown that what was previously considered a signature of criticality might also be the result of random processes. Researchers are still investigating that possibility, but many of them have already proposed new criteria for distinguishing between the apparent criticality of random noise and the true criticality of collective interactions among neurons.

Meanwhile, over the past 20 years, research in this area has steadily become more visible. The breadth of methods being used to assess it has also grown. The biggest questions now focus on how operating near the critical point affects cognition, and how external inputs can drive a network to move around the critical point. Ideas about criticality have also begun to spread beyond neuroscience. Citing some of the original papers on criticality in living neural networks, engineers have shown that self-organized networks of atomic switches can be made to operate near the critical point so that they compute many functions optimally. The deep learning community has also begun to study whether operating near the critical point improves artificial neural networks.

The critical brain hypothesis may yet prove to be wrong, or incomplete, although current evidence does support it. Either way, the understanding it provides is generating an avalanche of questions and answers that tell us much more about the brain — and computing generally — than we knew before.

Interview with Prof. Sean Carroll, Research Professor of Physics at Caltech and an External Professor at the Santa Fe Institute. We mainly talk about quantum spacetime: the idea that our familiar spacetime might be actually emergent from some complex quantum mechanical system. We cover entanglement, decoherence, entropic gravity, the AdS/CFT correspondence, string theory, black holes, along with several philosophical questions concerning these topics, including reduction and emergence, substantivalism vs. relationalism, monism, and much more.

Sean’s website: https://www.preposterousuniverse.com/
His recent book concerning these topics: https://www.preposterousuniverse.com/somethingdeeplyhidden/
His papers on these topics can be found here: https://www.preposterousuniverse.com/research/annotated-publications/
His podcast: https://www.preposterousuniverse.com/podcast/
And his Twitter: https://twitter.com/seanmcarroll/

Hong Kong plans to let retail investors trade digital tokens. It’s being seen as a major step toward its goal of becoming a crypto hub. Joanna Ossinger reports on Bloomberg Television.
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The “China Compound Eye” radar array aims to track and characterize potentially threatening deep-space objects.

Scientists from The Ohio State University have a new theory about how the building blocks of life—the many proteins, carbohydrates, lipids and nucleic acids that compose every organism on Earth—may have evolved to favor a certain kind of molecular structure.

It has to do with a concept called chirality. A geometric property inherent to certain molecules, chirality can dictate a molecule’s shape, chemical reactivity, and how it interacts with other matter. Chirality is also sometimes referred to as handedness, as it can be best described as the dichotomy between our hands: Though they are not identical, the right and the left hand are mirror images of each other, and can’t be superimposed, or exactly overlaid on one another.

In the journal ACS Earth and Space Chemistry, researchers now propose a new model of how the molecules of life may have developed their “handedness.”

Scientists try to unravel the birth, growth and power of black holes, some of the most forceful yet difficult-to-detect objects in our universe.

It was only last year that astronomers were finally able to unveil the first pictures of the supermassive black hole at the center of our Milky Way galaxy. But you couldn’t actually see the black hole itself, not directly. That’s because it is so dense that its gravitational pull prevents even light from escaping.

But the image of Sagittarius A, as our galaxy’s black hole is known, revealed a glowing halo of gas around the object—an object that we now know has a million times more mass than our sun.

Session kindly contributed by Silvester Sabathiel in SEMF’s 2021 Numerous Numerosity Workshop: https://semf.org.es/numerosity/

ABSTRACT
With the rise and advances in the field of artificial intelligence, opportunities to understand the finer-grained mechanisms involved in mathematical cognition have increased. A vast scope of related research has been conducted on machine learning systems that learn solving differential equations, algebraic equations and integrals or proofing complex theorems, all for which the preprocessed symbolic representations form the input and output types. However on the search for cognitive mechanisms that match the scope of humans when it comes to generalizability and applicability of mathematical concepts in the external world, a more grounded approach might be required. This involves starting with fundamental mathematical concepts that are earliest acquired in the human development and learning these within an interactive and multimodal environment. In this talk we are going to examine how artificial neural network systems within such a framework provide a controlled setup to discover possible cognitive mechanisms for intuitive numerosity perception or culturally acquired numerical concepts, such as counting. First we review impactful research results from the past, before I present the contributions of the work myself was involved in. Finally we can discuss the upcoming challenges for the field of numerical cognition and where this research journey could evolve to.

Continue reading “Neural Network Models of Mathematical Cognition | Silvester Sabathiel | Numerosity Workshop 2021” »

The skeleton cast of a Titanosaur is now on display at the American Museum of Natural History in New York. The 122-foot (37-meter) dinosaur skeleton is too long to fit in the exhibition hall, so its neck and head poke out toward the elevator banks, offering a surprise greeting when the doors open.