My guest this episode is Dr. Charles Zuker, PhD, Professor of Biochemistry, Molecular Biophysics and Neuroscience at Columbia University and an Investigator with the Howard Hughes Medical Institute. Dr. Zuker is the world’s leading expert in the biology of taste, thirst and craving. His laboratory explores the mechanisms of taste perception, focusing on how our conscious and unconscious processing of specific foods and nutrients guide our actions and behaviors. We discuss the neural circuits of taste, the “gut-brain axis,” the basis of food cravings and the key difference between wanting (craving) and liking (perceiving) sugar. We also explore how taste perception relates to specific food satiety, thirst, to our emotions, and expectation. We also consider how sugar containing and highly-processed foods can hijack the natural balance of the taste and digestive systems. Dr. Zuker provides a true masterclass in the biology of taste and perception that ought to be of interest to anyone curious about how the brain works, our motivated behaviors and the neural, chemical perceptual aspects of the mind. For the full show notes, visit hubermanlab.com. Thank you to our sponsors AG1 (Athletic Greens): https://athleticgreens.com/huberman LMNT: https://drinklmnt.com/huberman Thesis: https://takethesis.com/huberman Supplements from Momentous https://www.livemomentous.com/huberman Timestamps (00:00:00) Dr. Charles Zuker & Taste Perception (00:03:22) Sponsors: AG1, LMNT, Thesis, Momentous (00:08:35) Sensory Detection vs. Sensory Perception (00:11:48) Individual Variations within Perception, Color (00:16:20) Perceptions & Behaviors (00:20:19) The 5 Taste Modalities (00:26:18) Aversive Taste, Bitter Taste (00:28:00) Survival-Based & Evolutionary Reasons for Taste Modalities, Taste vs. Flavor (00:30:14) Additional Taste Modalities: Fat & Metallic Perception (00:34:02) Tongue “Taste Map,” Taste Buds & Taste Receptors (00:39:34) Burning Your Tongue & Perception (00:42:54) The “Meaning” of Taste Stimuli, Sweet vs. Bitter, Valence (00:51:55) Positive vs. Negative Neuronal Activation & Behavior (00:56:16) Acquired Tastes, Conditioned Taste Aversion (01:01:44) Olfaction (Smell) vs. Taste, Changing Tastes over One’s Lifetime (01:09:14) Integration of Odor & Taste, Influence on Behavior & Emotion (01:17:26) Sensitization to Taste, Internal State Modulation, Salt (01:24:05) Taste & Saliva: The Absence of Taste (01:28:10) Sugar & Reward Pleasure Centers; Gut-Brain Axis, Anticipatory Response (01:36:23) Vagus Nerve (01:43:09) Insatiable Sugar Appetite, Liking vs. Wanting, Gut-Brain Axis (01:52:03) Tool: Sugar vs. Artificial Sweeteners, Curbing Appetite (01:54:06) Cravings & Gut-Brain Axis (01:57:30) Nutrition, Gut-Brain Axis & Changes in Behavior (02:01:53) Fast vs. Slow Signaling & Reinforcement, Highly Processed Foods (02:10:38) Favorite Foods: Enjoyment, Sensation & Context (02:15:58) Zero-Cost Support, YouTube Feedback, Spotify & Apple Reviews, Sponsors, Momentous Supplements, Instagram, Twitter, Neural Network Newsletter Title Card Photo Credit: Mike Blabac Disclaimer
Dr. Charles Zucker, a professor of biochemistry, molecular biophysics and neuroscience, joins Andrew Huberman to talk about the nervous system's conversion of physical stimuli into the senses we experience.
Expert on perception and taste, Dr. John Hayes, discusses the unique set of sugar-sensing neurons found within the body and the communication between the brain and body that leads to our craving for sugar, which is often below conscious detection. The conversation also explores the ability of the nervous system to create perceptions and internal representations of the world around us.
In this podcast, the speaker discusses an experiment where they overlap red and green light to project yellow, and how people may see colors differently due to varying perceptions of light.
Our understanding of the brain's ability to compute, encode, and decode information can be explored through the sensory system of taste, which offers simplicity in input-output relationships while still tackling complex brain function questions.
This podcast discusses how our sense of taste, through the use of different taste receptors in the mouth, helps us identify foods that are necessary for our survival by activating neural circuits that induce either a reward response or aversion response.
Researchers have identified receptors for all five basic taste classes, including sweet, bitter, salt, umami, and sour, which can now be rigorously mapped to understand where they are found in the tongue. Additionally, there may be somatosensory cells that respond to the mechanical stimulation of fat molecules rolling on the tongue to create the perception of fat.
The brain has different areas that represent the taste of sweet and bitter. The taste signal travels through different stations before it reaches the cortex, and there are different groups of neurons associated with different taste perceptions in the brainstem.
The question of whether or not activated neurons in the brain are connected to areas that create a sense of valence or simply evoke distinct behaviors is raised, as well as the challenge of determining whether or not activating neurons is evoking a positive feeling or simply increasing licking.
This episode discusses the variability of taste preferences and how some people may enjoy fermented foods with a slight sour or briny flavor despite not liking bitter tastes. The podcast also touches on the evolutionary reasons behind why children may have an innate liking for sweet tastes.
The podcast discusses the relationship between odor and taste, how the context of a new relationship can alter perception, and how identifying corresponding areas in the brain can lead to meaningful scientific answers. There is no mention of a product being advertised.
The taste system is crucial for survival, as it ensures you get what you need but it can also be subjected to modulation by the internal state. Mice can be trained to differentiate between taste alone, odor alone, and the mix, similar to the visual system.
The taste system that drives our motivation to consume the necessary nutrients has to be flexible and modulated in response to the internal state of our body. Researchers are focusing on understanding how the taste system works in response to internal state modulation.
The gut-brain access and the reward pleasure centers of the brain can be activated by changes in our internal state, such as the levels of sugar and fat needed by the body, which are detected by the saliva in a fed or unfed state.
The vagus nerve is not only responsible for calming one's body down but also plays a role in stimulating the brain and creating a state of alertness. Scientists are trying to uncover the function and communication system of the nerve.
Artificial sweeteners can satisfy our tongue's preference for sweetness but they fail to activate the key sensors in our gut which inform our brain to stop craving sugar, leading to an equal preference for both sweet and non-sweet options, as seen in experiments conducted on mice.
The presence of intestinal sugar can influence the gut-brain circuit which can be hijacked by highly processed foods, leading to continuous reinforcement of wanting, not only of palatable foods but also appetitive ones. The brain is able to couple the taste of sweet drinks with the experience of nutrient extraction in the gut which is a slow system but is important for our survival.
In this podcast, the speaker shares her views on the sensory experience of food and how context influences perception. She also expresses her love for ethnic food and how the way it's presented can change the way it's tasted.