Summary
The Huberman Lab Podcast episode features an interview with Dr. David Berson, a Professor of Medical Science, Neurobiology and Ophthalmology at Brown University. They discuss the biology of vision, including how different wavelengths of light are interpreted by the brain to create the sensation of color. They also talk about the circadian clock, which is controlled by the suprachiasmatic nucleus (SCN) in the brain and how light exposure can impact the body's hormonal levels. The conversation then shifts to the vestibular system, which is responsible for detecting movement and balance, and how it works with the visual system to maintain balance. The episode also covers the basal ganglia, an area of the brain involved in controlling go-type and no-go type behaviors, and their importance in motor learning and skill execution. The hosts also discuss the complexity of the brain's neurons and how they work together to recognize faces and process information. The conversation ends with a mention of Thorne supplements and a discount code for listeners.
Dr. Berson introduces the concept of photopigments, chemicals that absorb light and convert it into a neural signal. There are five different types of photopigments in the eye, including one that is found in the innermost layer of the retina and is responsible for detecting brightness. This pigment is similar to those found in the eyes of insects, and its function is not fully understood. The scientist suggests that this pigment may play a role in regulating biological functions such as sleep and circadian rhythms. The circadian clock is an internal system that keeps time in the body, and it is controlled by the SCN in the brain. The SCN receives signals from a specialized set of neurons in the eye that sense light intensity and use that information to synchronize the body's clock to the external world. The clock in the SCN releases humeral signals, such as melatonin and adrenaline, that impact the autonomic nervous system and regulate alertness and calmness.
The conversation then shifts to the vestibular system, which is responsible for detecting movement and balance. The system is located in the inner ear and detects movement through hair cells. The conversation discusses how the brain uses multiple sensory systems to perceive motion and maintain balance. The vestibular system in the inner ear detects changes in head movement and rotation, while the visual system provides information about the environment. These two systems work together in the cerebellum, a mini-brain that coordinates movements and helps stabilize the image on the retina. Motion sickness occurs when there is a conflict between these two sensory systems, such as when looking at a stationary object while in motion.
The conversation then moves on to the basal ganglia, an area of the brain involved in controlling go-type and no-go type behaviors, and their importance in motor learning and skill execution. The cortex and basal ganglia work together to make decisions about behavior. The cortex is responsible for thinking through contingencies and deciding whether to withhold or execute behavior. The basal ganglia act as the disciplinarian or instructor, deciding when to start or stop behavior. The visual cortex is a representation of the visual world in our brains and is responsible for our ability to describe what we see. It is made up of dozens of maps that specialize in different aspects of visual information.
The conversation also covers the complexity of the brain's neurons and how they work together to recognize faces and process information. The brain's circuitry is both specific and non-specific, and neurons can have multiple functions. The story of a woman who lost her ability to read braille after a stroke in her visual cortex demonstrates the brain's ability to repurpose unused areas for other functions. The concept of a connectome, a complete description of the synaptic wiring of a chunk of nervous tissue, is discussed as a way to revolutionize the understanding of the brain's connectivity and hardware.
Overall, the episode provides a fascinating insight into the biology of vision, the circadian clock, the vestibular system, and the basal ganglia, as well as the complexity of the brain's neurons and how they work together to recognize faces and process information. The hosts also provide suggestions for people who want to learn more about neuroscience.
