In this episode, Richie Davidson and Cortland Dahl deeply explore the science of the emotional brain: why the mind is a storyteller, what split-brain research reveals about consciousness, how brain asymmetry shapes emotion, why some people approach opportunity with optimism while others withdraw, and what meditation may do to the brain and immune system. Enjoy! See below for FLASHCARDS, Full Transcript Below Watch on Youtube; Listen on Spotify or Apple Podcasts. FLASHCARDS / EPISODE COMPANION HERE Podcast Chapter List (00:00:00) – The brain is a storyteller (00:01:03) – Welcome to Dharma Lab (00:04:05) – Norman Geschwind and behavioral neurology (00:06:31) – The thumbtack story: emotional memory without conscious memory (00:12:12) – Language, the left hemisphere, and the corpus callosum (00:19:04) – Brain asymmetry and emotion (00:22:54) – Why emotion was so understudied (00:29:26) – Brain asymmetry, attachment, and aversion (00:31:19) – The prefrontal cortex and the old divide between thought and feeling (00:37:07) – Studying emotion in newborn infants (00:42:37) – Meditation, brain asymmetry, and the immune system (00:47:04) – Why “it’s not so simple” Written transcript for those who prefer to read Lightly edited for clarity and readability. The Brain Is a Storyteller (00:00:00) Cortland Dahl:The example you gave earlier, with Broca’s area and the split-brain findings, points to something fascinating. Parts of the brain are not always talking to each other. One part of the brain clearly knows something, but the part that communicates doesn’t. And it doesn’t stay silent. It makes something up. That’s the funny thing. In the absence of information, we don’t just stay silent. When we don’t know something, we are not comfortable with not knowing. Some instinctual part of us fills in the blanks almost all the time. Richard Davidson:Exactly. The human mind and brain is a storyteller. This is how we make sense of our world. We create these narratives. Welcome to Dharma Lab (00:01:03) Cortland Dahl:Welcome everyone to another episode of Dharma Lab. I’m Cortland Dahl, and I’m here with Dr. Richard Davidson, who we all lovingly call Richie. As many of you know, Richie is one of the most pioneering and widely studied neuroscientists on the planet. It’s a gift to be in conversation with him. Today we’re going to have a conversation I’ve wanted to have for a long time. I moved to Madison, Wisconsin in 2012 to study with Richie, and over the years I’ve heard many conversations at the Center for Healthy Minds about neuroscience, meditation, and the mind. But one thing that has never really happened, even for those of us who work closely with Richie, is a kind of broad “download” from him about the amazing body of work he has contributed to over the decades. Many people know Richie as a pioneer of contemplative science and contemplative neuroscience, the scientific study of how practices like meditation affect the mind, the brain, and our biology. But he is also a pioneer of affective neuroscience, which you might think of as the neuroscience of emotion. To be a pioneer in one field is extraordinary. To be a pioneer in two is kind of mind-boggling. So today I want to dig into some of those key insights, especially around neural asymmetry, which was a huge part of Richie’s early career and a central theme in affective neuroscience. Norman Geschwind and Behavioral Neurology (00:04:05) Richard Davidson:This topic is near and dear to my heart. It still is something I’m extremely interested in. It really began when I was a graduate student and had the opportunity to study with Norman Geschwind at Harvard Medical School. Geschwind was one of the great towering figures in what we now call behavioral neurology. I took a course with him on functional neuroanatomy, which is basically how different parts of the brain are connected to different behavioral functions. He was a neurologist, so he looked at people’s behavior as an external reflection of what was going on in the brain. He was an extremely keen observer of behavior, and he was also very demanding. He was what we would now call a localizationist, someone who believed in the specific localization of different functions in different parts of the brain. He used to say that if you don’t believe in localization, it’s because you don’t know neuroanatomy well enough. That pushed me to learn neuroanatomy deeply, including doing a human brain dissection. I also went on rounds with him, where he would visit neurological patients in the hospital. He would do these bedside exams that were incredible, using clever ways of interacting with patients to reveal what might be different about their brains. The Thumbtack Story: Emotional Memory Without Conscious Memory (00:06:31) Richard Davidson:One of the most famous demonstrations I saw involved a technique associated with Korsakoff, who described a syndrome of dementia related to alcoholism. Korsakoff showed that there can be a separation between memory for declarative information and memory for emotional information. A person with severe dementia might not recognize you if you came back the day after seeing them. They may have no conscious memory of who you are. But the question was whether the same was true for emotional information. The demonstration was this: a doctor would put a thumbtack in his hand and shake the patient’s hand. The patient would feel the prick and withdraw. The next day, the doctor would return and ask, “Do you know who I am?” The patient would say no. The doctor would identify himself and offer his hand again. But the patient refused to shake his hand. When asked why, the patient confabulated. He said something like, “I think your hand is dirty, and I don’t want to shake your hand.” That’s a beautiful demonstration of the dissociation between declarative memory and emotional memory. The declarative memory was gone. The patient did not recognize the doctor’s face or name and had no conscious memory of having seen him. But the emotional memory remained. Cortland Dahl:That one point has huge implications for life. We often have an interpretation of something and we are completely convinced of it. It seems so real that it doesn’t occur to us that it’s an interpretation. And yet the mind may have limited information, or may not be conscious of something, and it creates a whole story. In some cases, the story is flat-out wrong. But in the moment, it feels like reality. Richard Davidson:Exactly. And this is not just occurring in patients with frank brain damage. This is happening in all of us all the time. This is how our minds work. The mind creates a story about the world, and it’s from that story that we operate. It is not from some veridical perception of things in the world. There is no such thing as that. Our minds are constantly creating these stories. This relates directly to our insight pillar of well-being, which is about the narratives we are constantly creating about ourselves. Language, the Left Hemisphere, and the Corpus Callosum (00:12:12) Richard Davidson:One of Geschwind’s great contributions was his work on language-related lateralization in the human brain. In virtually all right-handed people, which is about 85 to 90 percent of the population, it is the left hemisphere that can speak, while the right hemisphere cannot. There is a key region called Broca’s area, named after Paul Broca. Damage to this area, often through stroke, can impair a person’s ability to speak. What is interesting is that this is one of the most clearly lateralized functions in the human brain. If this area in the left hemisphere is damaged, the corresponding area in the right hemisphere does not simply take over. The two hemispheres of the brain are very similar in many ways, but they have important differences. They are connected by the corpus callosum, a massive bundle of white matter that connects neurons in one hemisphere to corresponding neurons in the other. It is the largest pathway of connection in the human brain. In the past, for some patients with severe epilepsy, surgeons would cut the corpus callosum to prevent seizures from spreading from one hemisphere to the other. This left people with two disconnected hemispheres. When that happens, you can demonstrate strange dissociations. For example, if a split-brain patient is blindfolded and holds a glass in the left hand, the sensory information goes to the right hemisphere. But because the right hemisphere cannot speak, and the information cannot cross to the left hemisphere, the person may not be able to verbally identify the object. If you give them multiple-choice pictures, though, they can point to the glass. Cortland Dahl:That’s the same basic finding. One part of the brain clearly knows something, but the part that communicates doesn’t. And it doesn’t stay silent. It makes something up. Brain Asymmetry and Emotion (00:19:04) Richard Davidson:Most early research on brain asymmetry focused on the back of the brain, where language and some perceptual differences were located. The left hemisphere was specialized for speech and language. The right hemisphere seemed better at certain visual-spatial skills. But another early observation was especially interesting: when patients had damage to the left hemisphere, especially including the left prefrontal region, they were more likely to show depression after the brain damage. Two people could have comparable amounts of damage, but if the damage was in different hemispheres, the emotional consequences could be different. That led to the conjecture that the left hemisphere might play some role in emotions that are antithetical to depression. These patients often seemed anhedonic, meaning they were not experiencing much pleasure. There were also clinical reports of patients with right-hemisphere damage, whose left hemisp
