Essentials: How Your Brain Works & Changes

Andrew Huberman, who introduces himself as a professor of neurobiology and ophthalmology at Stanford School of Medicine, frames this Huberman Lab Essentials episode as a tour of the "parts list of the nervous system." He admits the topic "might sound boring," but argues that these parts together produce everything in a person's experience: what they think, feel, imagine and accomplish, from birth until death. He also promises listeners they will understand more about how they work and how to apply that knowledge.

His first move is to widen the frame from the brain to the whole nervous system. He describes the brain as "just one piece" of a larger system that includes the spinal cord, the connections from brain and spinal cord to the body's organs, and, which he stresses as very important, the connections running from the organs back to the spinal cord and brain. On this view, thought, memory, feeling and imagination all come from a two-way flow of signals between brain, spinal cord and body.

In fact, we really can't even separate them. It's one continuous loop.

To explain how this system encodes experience, Huberman uses a piano analogy. Keys played in a particular order and with a particular intensity make a given song, and he likens that song to a given experience. He adds a qualification: people arrive in the world with a brain that has "a kind of bias towards learning particular kinds of things" and is ready to take in information. Even so, he repeats his central claim that the brain is "really a map of experience."

Our brain is really a map of our experience.

Huberman says the nervous system "really does five things, maybe six." The hedge stays open in this part of the episode. He goes on to describe five functions (sensation, perception, feelings/emotions, thoughts and actions) and never names a sixth.

Sensation: a "non-negotiable element" of the nervous system, carried out by sensory receptors. Neurons in the eye perceive certain colors of light and certain directions of movement. Neurons in the skin perceive light, firm or painful touch. Neurons in the ears perceive certain sounds. Perception: the ability to focus on what is being sensed, make sense of it, explore it and remember it. Huberman defines perceptions as "just whichever sensations we happen to be paying attention to at any moment."

Because perception depends on attention, he spends time on how attention works. He compares it to a spotlight, but says humans have two attentional spotlights. He ties this to what he calls covert attention in old world primates, the group that includes humans. One spotlight can rest on something being read, watched or listened to, while the second rests on something else, such as how food tastes, a child running around the room, or his dog. Attention can also be brought to a single location, and it can be dilated to make the spotlight more diffuse or narrowed to make it more concentrated.

Anyone that tells you you can't multitask, tell them they're wrong, and if they disagree with you, tell them to contact me.

This is the most openly contrarian claim in the segment. Huberman supports it by pointing to the covert-attention capacity of old world primates. In this part of the conversation he does not cite specific studies or say how well performance holds up when attention is split.

From there he draws what he calls a point that is "very important to understand" for anyone looking for tools to improve their nervous system: "Attention is something that is absolutely under your control." He divides nervous system activity into reflexive and deliberate modes. Deliberate, "top-down" thought takes effort and focus, and he says it "will always feel like it requires some effort and some strain." Reflexive activity such as walking, talking and eating feels easy because the nervous system is wired to do most things without much metabolic demand. Trying to do something very specific produces what he calls "a sort of mental friction." He presents that friction as a normal feature of deliberate control, not a sign that something is going wrong.