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"Brain imaging is not a very good way to test subtle distinctions [in the brain]...it's like trying to find out something about New York City by studying New York State," says NYU neuroscientist Joseph LeDoux, one of the pioneers of neuroscientific animal research back in the 1970s. "Animal research is so important because we can go in and study individual cells and individual synapses on those cells," he says. But can we take the information we learn about the brains of rats and apply that knowledge to the endlessly complex human brain?
In his second Big Think interview, LeDoux told us that, yes, we can learn much from studying rats' brains, even about things like emotion, which we often attribute solely to humans. "Through the history of psychology, there's been a struggle between what can we learn about psychological states in humans and animals, what can we learn about psychological states by studying conscious states in people and unconscious states," LeDoux explains. In the 1930s and '40s, the behaviorists threw out the idea of consciousness because it is a subjective pehnomenon that cannot be measured. Then the cognitive revolution of the '50s and '60s brought the mind back to psychology, "but it didn't bring back the mind that the behaviorists got rid of," says LeDoux. "When I got interested in emotion in the '70s, emotion was still being thought of in terms of subjective conscious experiences, whereas other aspects of psychology, like perception and memory were thought of as information processing functions." LeDoux revolutionized the study of emotion, especially of fear, by thinking about it in terms of observable behavior. "All animals have to be able to detect danger and respond to danger in order to stay alive, including humans." And because this is such a basic evolutionary adaptation, it functions quite similarly between animals and humans.
The hub of all emotional processing in both human and animal brains is the amygdala, says LeDoux, also the frontman of a rock group called The Amygdaloids. He has spent his career studying this almond-shaped structure, and he gave us a five minute primer on everything we should know about it. "What the amygdala is doing is forming associations between random or neutral external stimuli and the kinds of reinforcing events that will stamp in those experiences in a stronger way," he says. "So its creating what's called Pavlovian associations: you know, stimulus one plus stimulus two; if one of those is a biologically significant stimulus, then the other one will acquire some kind of biological significance itself, whether it’s positive or negative."
LeDoux also talked to us about some of the groundbreaking research to have come out of his his lab in recent years. One discovery dealt with a process called "reconsolidation" of memory. "When you retrieve a memory it becomes unstable and new information can be incorporated into the memory at that point," he says. "It also means that when the memory is unstable, its restabilization process can be blocked. And if you block that, the memory is weakened or dampened. So that's how we've been using reconsolidation to help people with traumatic memories to try and dampen their memories of those traumatic situations."
LeDoux also told us about his current studies of rats with extreme fear. "We can compare animals that are really afraid and those that are not afraid and look in their brains and see if there area any, for example, structural differences in the amygdala."
Scientists find 16 'ultra-black' fish species that absorb 99.9% of light
These alien-like creatures are virtually invisible in the deep sea.
A female Pacific blackdragon
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian
<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p>A crested bigscale
Credit: Karen Osborn/Smithsonian
<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p>Pacific viperfish
David Csepp, NMFS/AKFSC/ABL
<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </p>'Deep Nostalgia' AI brings old photos to life through animation
Using machine-learning technology, the genealogy company My Heritage enables users to animate static images of their relatives.
- Deep Nostalgia uses machine learning to animate static images.
- The AI can animate images by "looking" at a single facial image, and the animations include movements such as blinking, smiling and head tilting.
- As deepfake technology becomes increasingly sophisticated, some are concerned about how bad actors might abuse the technology to manipulate the pubic.
My Heritage/Deep Nostalgia
<p>But that's not to say the animations are perfect. As with most deep-fake technology, there's still an uncanny air to the images, with some of the facial movements appearing slightly unnatural. What's more, Deep Nostalgia is only able to create deepfakes of one person's face from the neck up, so you couldn't use it to animate group photos, or photos of people doing any sort of physical activity.</p>My Heritage/Deep Nostalgia
<p>But for a free deep-fake service, Deep Nostalgia is pretty impressive, especially considering you can use it to create deepfakes of <em>any </em>face, human or not. </p>When does an idea die? Plato and string theory clash with data
How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0
<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p>Can you still spread coronavirus after getting the vaccine?
The vaccine will shorten the "shedding" time.
