Boost Attention & Memory with Science-Based Tools | Dr. Wendy Suzuki

Andrew Huberman introduces Dr. Wendy Suzuki as a professor of neuroscience and psychology at New York University and a leading researcher on learning and memory. He credits her laboratory with fundamental, textbook understanding of how the hippocampus and related brain circuits take certain experiences and commit them to memory so the information can be used later. He also points to her widely viewed TED talk, in which she describes using exercise to enhance learning and memory.

According to Huberman, that personal experience led Suzuki to reshape her laboratory around how meditation, exercise and other physiological and psychological practices might help people learn faster, retain memories longer and change cognitive performance. He notes that she is the incoming Dean of Arts and Science at NYU, and says she told him her program will bring exercise, meditation and other behavioral practices into efforts to improve student learning and stress management.

Huberman lists her books, "Good Anxiety: Harnessing the Power of the Most Misunderstood Emotion" and "Healthy Brain, Happy Life: A Personal Program to Activate Your Brain and Do Everything Better." He concedes that the second is "admittedly a very pop science-type title," but stresses her standing as a memory researcher. He frames the episode as covering how memories form, how they are lost, and which tools listeners can use to learn and remember better. He adds that the podcast is separate from his teaching and research roles at Stanford.

Huberman opens with an everyday example: an unremarkable mug of tea that may now become memorable just because he has talked about it. He asks what happens in the brain when something ordinary is marked as special.

Well, I like to say there are four things that make things memorable.

Novelty: the first time we see or experience something, our attentional systems draw us to it, and paying attention is part of what makes things memorable. Repetition: seeing the same cup of tea every day and talking about it in every interview means you will remember it. Association: a new person who knows many people you already know is easier to remember. Emotional resonance: we remember the happiest and saddest moments of our lives, along with funny and surprising things.

Suzuki connects the fourth feature to two brain structures. The amygdala processes emotional situations, particularly threatening or surprising ones, and in those situations it makes the hippocampus work better at putting new long-term memories into the brain. She calls the hippocampus "the key structure for long-term memory."

Huberman says many people of his generation first heard the word hippocampus in the film "Memento." He admits that even as a neuroscientist he finds the hippocampus less clear-cut than vision, where the jobs of the eye, thalamus and cortex are well defined, so he asks Suzuki for an updated account of its structure and function.

Suzuki starts with anatomy. The word hippocampus means seahorse, and the structure has a curled, seahorse-like shape with intertwining subregions. She suggests that this striking shape, deep in the brain, is one reason early anatomists were drawn to it.

For function, she argues that the clearest evidence comes from what happens when the hippocampus is lost, and she turns to patient H.M., "the most famous neurological patient of all time." He was operated on in 1954, and the paper was published in 1957. Because his epilepsy was severe and the hippocampus was known to be its origin, surgeons took the experimental step of removing both hippocampi rather than one. The result was an immediate loss of all ability to form new memories for facts and events.

Suzuki explains that the hippocampus works on the stream of perceptions we receive every minute, but not on all of them. It works on those with the features she listed earlier: novelty, association, emotional relevance or repetition. Some of those facts and events are then encoded into long-term memory. She adds a personal reason for studying the structure:

the hippocampus and what it does really defines our own personal histories.

Her reasoning is that if we cannot remember what we have done, what we have learned and the events of our lives, it changes who we are.

Suzuki argues that "the hippocampus is important for memory" is too simple a statement. She describes a newer view in which the hippocampus does more than bind the what, where and when of past events: it also recombines information from long-term memory in new ways. Her main example is imagination. Without a hippocampus, a person cannot remember things and is also unable to imagine events or situations they have never experienced.

Anytime you need to associate something together, either for your past, your present, or your future, you are using your hippocampus.

Huberman restates this as the hippocampus setting context with elements from the past, present or future. He links it to the neuroscientific idea of the time domain, as opposed to evaluating things only in space, and Suzuki agrees that this aspect of hippocampal function is interesting.

Huberman asks a true-or-false question based on high-profile reviews from a few years earlier. Those reviews held that the hippocampus encodes memories but does not store them, and that storage happens in the neocortex.

Suzuki calls this "a tricky statement." She accepts that long-term memories are ultimately stored in the cortex. But she says memories are sometimes stored in the hippocampus for a very long time, which makes the cutoff unclear: if a memory sits there for four years, does it still count as not being stored in the hippocampus? She acknowledges that the question was actively debated and that some researchers rejected the idea of the hippocampus as a storage area. Her own position is more cautious:

But I think it's a long, long, long-term kind of intermediate storage area.

Huberman offers H.M. as evidence: H.M. could still recall facts from before his surgery but could not form new memories, which seems to support the idea that some memories are kept outside the hippocampus. Suzuki adds a qualification. H.M. still had part of his posterior hippocampus. She says the neurosurgeon, Scoville, overestimated how many millimeters of hippocampus he intended to remove, and a historic MRI later in H.M.'s life showed the intact posterior portion. This complicates interpreting H.M.'s case. She also notes more generally that interpreting any lesion in a patient is complicated, even though H.M. holds a "mythical role" in neuroscience and neurology.

Huberman turns to one-trial learning, where a single experience creates a memory without repetition. He observes that the nervous system seems skewed toward forming such memories for negative events, which he describes as an adaptive survival mechanism. He asks whether the amygdala-to-hippocampus connection explains this. He also notes that every brain area is ultimately connected to every other, and the real question is through how many nodes.

Suzuki agrees that the brain has a protective function, which she says evolved over the last 2.5 million years, for attending to and remembering things that matter for survival. Some memories formed this way are fear memories. She gives a personal example. While living in Washington, D.C., she came home from work at NIH on a Sunday afternoon and found her apartment door had been crowbarred open and the nicest things in the apartment stolen. Afterward, every time she rounded that corner she still had the memory, and it put her in a terrible state just from coming home.