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Showing results for tags 'Brain'.
For all you AI and Singularity geeks out there, I found this article entitled "How to Build a Mind?" really interesting and intuitive. It is about a new theory that attempts to integrate recent findings from both neuroscience and deep learning. It explains how the hippocampus encodes recent episodic memories of life events, and then plays them back while we sleep in order to "train" the neocortex. This is very similar to the approach used by the folks at DeepMind to teach AlphaGo using a combination of supervised learning and reinforcement learning. In fact, Demis Hassabis, founder of DeepMind, was a co-author on the paper, along with neuroscientist Jay McClelland from Stanford - a former colleague and collaborator of mine during the earlier days of artificial neural networks while we were both at CMU, along with neural net pioneer Geoff Hinton, who is also now at Google. In fact, most of the smartest people I've ever worked with (literally, at least 10 people I can think of off the top of my head) now work at Google... Which reminds me, earlier today I watched a really good video (embedded below) by Demis about DeepMind, AlphaGo and the future of AI. Demis describes in very accessible detail (starting at 28:15) the way AlphaGo works, and how it was trained (by playing against itself millions of times) to beat Lee Se-Dol, one of the world's top human Go players. I predict that DeepMind's approach to the development of artificial general intelligence may actually work, and come to fruition in the next couple decades. That will really make things interesting. I usually shy away from offering investment advice, but for those of you who haven't but can afford to, I recommend investing at least a little of your retirement savings in Google as an insurance policy against technological unemployment. When and if a Google AI steals all the jobs, you'll be glad you did... --Dean https://www.youtube.com/watch?v=f71RwCksAmI
This is a fascinating NY Times article about recent success by researchers in restoring metabolic function to a recently severed pig brain, retrieved from a slaughterhouse. Very Frankenstein-esque, but for real. Here is one of the most interesting paragraphs, along with a link to the Nature article  about the research. By any measure, the contents of the paper Sestan and his team published in Nature this April were astonishing: Not only were Sestan and his team eventually able to maintain perfusion for six hours in the organs, but they managed to restore full metabolic function in most of the brain — the cells in the dead pig brains took oxygen and glucose and converted them into metabolites like carbon dioxide that are essential to life. “These findings,” the scientists write, “show that, with the appropriate interventions, the large mammalian brain retains an underappreciated capacity for normothermic restoration of microcirculation and certain molecular and cellular functions multiple hours after circulatory arrest.” The researchers are understandably conservative. They utilize blockers to keep neurons from firing in any coherent way, although they did observe spontaneous neural spiking (see abstract below). They also acknowledge that less scrupulous (or more ambitious, depending on your perspective) researchers could quite concieveably attempt to restore normal neural activity to the harvested brain. They also say that pig anatomy isn't that different from human anatomy, so the same technique (with some modifications) should work for a human brain, should anyone be bold enough to try it. Pretty amazing to think that someday a "brain in a vat" scenario might actually become reality. Without any sensory input or motor output, it would probably be a very unpleasant experience, if it would be conscious at all. --Dean ---------------------------  Nature. 2019 Apr;568(7752):336-343. doi: 10.1038/s41586-019-1099-1. Epub 2019 Apr 17. Restoration of brain circulation and cellular functions hours post-mortem. Vrselja Z(1)(2), Daniele SG(1)(2)(3), Silbereis J(1)(2), Talpo F(1)(2)(4), Morozov YM(1)(2), Sousa AMM(1)(2), Tanaka BS(5)(6)(7), Skarica M(1)(2), Pletikos M(1)(2)(8), Kaur N(1)(2), Zhuang ZW(9), Liu Z(9)(10), Alkawadri R(6)(11), Sinusas AJ(9)(10), Latham SR(12), Waxman SG(5)(6)(7), Sestan N(13)(14)(15)(16)(17)(18)(19). The brains of humans and other mammals are highly vulnerable to interruptions in blood flow and decreases in oxygen levels. Here we describe the restoration and maintenance of microcirculation and molecular and cellular functions of the intact pig brain under ex vivo normothermic conditions up to four hours post-mortem. We have developed an extracorporeal pulsatile-perfusion system and a haemoglobin-based, acellular, non-coagulative, echogenic, and cytoprotective perfusate that promotes recovery from anoxia, reduces reperfusion injury, prevents oedema, and metabolically supports the energy requirements of the brain. With this system, we observed preservation of cytoarchitecture; attenuation of cell death; and restoration of vascular dilatory and glial inflammatory responses, spontaneous synaptic activity, and active cerebral metabolism in the absence of global electrocorticographic activity. These findings demonstrate that under appropriate conditions the isolated, intact large mammalian brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval. DOI: 10.1038/s41586-019-1099-1 PMID: 30996318