Learning and Memory

Charan Ranganath admits he can be forgetful. This is true of most people, but most people are not leading experts on the neuroscience of human memory.

“Everybody knows I have a terrible memory,” said Ranganath, a professor of psychology and core faculty member at the Center for Neuroscience, “and yet I got a Ph.D., and I publish papers all the time. I'm totally functional, so maybe the expectations we have are just wrong.”

Why does memory fade? Why does it stay?

These questions, among others, occupy the mind of Charan Ranganath, a UC Davis psychology professor in the College of Letters and Science and a core faculty member with the Center for Neuroscience. But the transient nature of memory isn’t just a focal point of Ranganath’s research. It’s something that he, like the rest of us, deals with daily.

People love stories. We find it easier to remember events when they are part of an overarching narrative. But in real life, the chapters of a story don’t follow smoothly one from another. Other things happen in between. A new brain imaging study from the Center for Neuroscience at the University of California, Davis, shows that the hippocampus is the brain’s storyteller, connecting separate, distant events into a single narrative. The work is published Sept. 29 in Current Biology.

Charan Ranganath, Ph.D., UC Davis professor of psychology at the Center for Neuroscience, was a guest on the Every Little Thing podcast episode Memory Game: Did This Meal Really Happen? on May 10, 2021. Dr. Ranganath spoke with hosts Annette Heist and Jorge Just about how we form memories and the tricky nature of deciding about whether a memory is "true." Listen to the full episode here.

Professor Charan Ranganath, UC Davis Center for Neuroscience, talks about the latest advances in understanding memory, in particular memory and the healthy aging brain, and PTSD. 

Ranganath was interviewed by Davis Community Television host Lin Weaver on June 13, 2019. 

Researchers have revealed a new brainwave device that supposedly boosts our ability to remember significantly more information.

A device that gives us a significantly enhanced memory has long been a trope of science fiction, and perhaps the dreams of many a student. Now, researchers at University of California, Davis, have revealed a somewhat similar device that enhances brainwaves crucial to our ability to recall information.

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An audio clip from the Apollo 11 launch plays amid static. “Ignition sequence start,” a voice says. “Six, five, four, three…” As the countdown continues, the feedback swells in the background, as if an amplifier’s volume knob is slowly being turned up. “All engines running,” the voice says. “Liftoff.”

Christine Blasey Ford drew heavily on her psychology background while giving an emotional testimony about her alleged sexual assault by Supreme Court nominee Brett Kavanaugh, discussing everything from brain chemistry to risk factors for anxiety.

Vastly more advanced than any supercomputer, the complexity and versatility of the human brain is awe-inspiring. Of all its abilities, learning from new experiences might be the most powerful and astounding feature. But how does learning occur? And how do we remember what we learn? 

Of all the social gaffes, none is perhaps more common than meeting a new person, exchanging names and promptly forgetting theirs — forcing you to either swallow your pride and ask again, or languish in uncertainty forever.

Why do we keep making this mistake? There are a few potential explanations, says Charan Ranganath, the director of the Memory and Plasticity Program at the University of California, Davis.

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When making memories, certain neurons form larger, denser connections, according to a study published today (April 26) in Science.

Scientists have long attempted to understand where, and how, the brain stores memories. At the beginning of the 20th century, German scientist Richard Semon coined the term “engram” to describe the hypothetical physical representations of memories in the brain.

Why do we remember some events, places and things, but not others? Our brains prioritize rewarding memories over others, and reinforce them by replaying them when we are at rest, according to new research from the University of California, Davis, Center for Neuroscience, published Feb. 11 in the journal Neuron.

“Rewards help you remember things, because you want future rewards,” said Professor Charan Ranganath, a UC Davis neuroscientist and senior author on the paper. “The brain prioritizes memories that are going to be useful for future decisions.”

In a study published online in JAMA Psychiatry, John Daniel Ragland, Ph.D. and Cameron Carter, M.D. combined previously established tests for cognitive function with fMRI to pinpoint how memory and brain function change in patients with schizophrenia.

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Dr. Ranganath and his team are featured in this Sacramento News & Review article on why our memories are so inaccurate.

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