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The Amygdala and Unconscious Memories
Joseph LeDoux is a professor and a member of the Center for Neural Science and Department of Psychology at NYU. His work is focused on the brain mechanisms of emotion and memory. In addition to articles in scholarly journals, he is author of "The Emotional Brain: The Mysterious Underpinnings of Emotional Life" and "Synaptic Self: How Our Brains Become Who We Are." He is a fellow of the American Association for the Advancement of Science, a fellow of the New York Academy of Science, a fellow of the American Academy of Arts and Science, and the recipient of the 2005 Fyssen International Prize in Cognitive Science. LeDoux is also a singer and songwriter in the rock band, The Amygdaloids.
Professor LeDoux is a Big Think Delphi Fellow.
Question: Can we think of the amygdala as the seat of what Freud called the unconscious?
Joseph LeDoux: I think it’s a distraction because... I mean, it’s true in the sense that the hippocampus is necessary to have a conscious recollection of some past event, and the amygdala participates in unconscious memory. But we shouldn’t really taint it with the Freudian concepts because that adds a lot of baggage.
The amygdala is an unconscious processor because it’s just not connected with the conscious system. It’s kind of like by default unconscious as opposed to being in the Freudian sense of unconscious something that was conscious, but was too anxiety-provoking and therefore shipped to the unconscious. The amygdala gets direct sensory information and it learns and stores information on its own, and that information that’s stored then controls emotional responses. The connectivity is hardwired, so one way to think about it is that a rat will respond to a cat without any learning by freezing, raising its blood pressure and heart rate and respiration and releasing stress hormones. But it will also respond to a stimulus associated with a cat and have the same responses.
So you don’t learn how to be afraid, your amygdala doesn’t have to learn what to do, it learns what to do it in response to. So it learns what stimuli it should respond to. So it’s learning and memory in that sense that we call an implicit kind of memory where you don’t have to have any conscious involvement.
Whereas, the hippocampus is necessary to have a conscious memory. So, yes, they do participate in conscious and unconscious memories, but not in the Freudian sense. But there’s a whole other side of the amygdala’s role in memory, which is that when the amygdala is activated and all of those hormones and other things happened to get released, that provides information that feeds back to parts of the brain, like the hippocampus and allows them to store their memories in a much more efficient and strong way. So we know that emotional memories are stored more vividly than other kinds of memories. It used to be thought that they were more accurate, but in fact now we know that they are not more accurate, they’re just more vivid and strong in the personal sense. But they can be highly inaccurate. This is shown by studies of natural disasters and so forth, well not always so natural. But like the Space Challenger Shuttle... or the shuttle, Space Shuttle Challenger explosion, a lot of people witnessed that and they were studied almost immediately by psychologists who made notes of exactly what their responses, what they were experiencing at the time and then a year later, they were surveyed again and the responses were completely different from what they remembered originally and then several years later it completely changed again.
So what we remember is not necessarily what we experienced originally. So the accuracy of those memories changes over time, but their strength in terms of your subjective feeling that it was a really powerful experience is there.
Recorded on September 16, 2010
Interviewed by Max Miller
The amygdala is responsible for implicit memories, but these are different from what Freud called the unconscious.
Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.
- The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
- Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
- Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Bacteria under microscope
needpix.com<p>Today, bubonic plague can be treated effectively with antibiotics.</p><p style="margin-left: 20px;">"Unlike in the 14th century, we now have an understanding of how this disease is transmitted," Dr. Shanthi Kappagoda, an infectious disease physician at Stanford Health Care, told <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">Healthline</a>. "We know how to prevent it — avoid handling sick or dead animals in areas where there is transmission. We are also able to treat patients who are infected with effective antibiotics, and can give antibiotics to people who may have been exposed to the bacteria [and] prevent them [from] getting sick."</p>
This plague patient is displaying a swollen, ruptured inguinal lymph node, or buboe.
Centers for Disease Control and Prevention<p>Still, hundreds of people develop bubonic plague every year. In the U.S., a handful of cases occur annually, particularly in New Mexico, Arizona and Colorado, <a href="https://www.cdc.gov/plague/faq/index.html" target="_blank">where habitats allow the bacteria to spread more easily among wild rodent populations</a>. But these cases are very rare, mainly because you need to be in close contact with rodents in order to get infected. And though plague can spread from human to human, this <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">only occurs with pneumonic plague</a>, and transmission is also rare.</p>
A new swine flu in China<p>Last week, researchers in China also reported another public health concern: a new virus that has "all the essential hallmarks" of a pandemic virus.<br></p><p>In a paper published in the <a href="https://www.pnas.org/content/early/2020/06/23/1921186117" target="_blank">Proceedings of the National Academy of Sciences</a>, researchers say the virus was discovered in pigs in China, and it descended from the H1N1 virus, commonly called "swine flu." That virus was able to transmit from human to human, and it killed an estimated 151,700 to 575,400 people worldwide from 2009 to 2010, according to the Centers for Disease Control and Prevention.</p>There's no evidence showing that the new virus can spread from person to person. But the researchers did find that 10 percent of swine workers had been infected by the virus, called G4 reassortant EA H1N1. This level of infectivity raises concerns, because it "greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses," the researchers wrote.
The word "learning" opens up space for more people, places, and ideas.
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- Selfish behavior has been analyzed by philosophers and psychologists for centuries.
- New research shows people may be wired for altruistic behavior and get more benefits from it.
- Times of crisis tend to increase self-centered acts.