00:00 This episode of the podcast discusses chemical sensing, including the sense of smell, taste, and the effects of chemicals on our biology.

06:35 Chemicals, including volatile chemicals that we smell and taste, as well as pheromones, have the ability to enter our bodies and fundamentally change our biology.

13:43 Chemicals in tears, specifically those evoked by sadness, have been shown to reduce testosterone levels and brain areas associated with sexual arousal in men who smell them, highlighting the powerful effects of chemicals on our biology and interpersonal communication.

21:11 The act of smelling, specifically inhaling through the nose, increases alertness, attention, and the ability to learn and remember information, while exhaling has the opposite effect, suggesting that nasal breathing during focused work can enhance cognitive function.

28:56 Practicing nasal breathing and enhancing your sense of sniffing can improve cognition, learning, and perception of smells and tastes.

35:40 Enhancing your sense of smell through nasal breathing and sniffing can improve your relationship with food, increase discernment of different odors, and potentially indicate brain health.

42:10 Enhancing your sense of smell through interacting with odors and inhaling more can help create new neurons, and this is particularly important for individuals who have experienced head injuries or repeated head injuries.

48:48 Enhancing the olfactory system can be used for the treatment of traumatic brain injury, and smelling salts can have a psyching up effect and increase force development, while the ability to smell in dreams is diminished during REM sleep but can still be measured and has clinical implications for assessing brain function.

55:18 The sense of smell varies from person to person due to genetic differences in olfactory receptors, and taste receptors are not distributed differently on the tongue as previously believed.

01:02:37 The taste system consists of sweet, salty, bitter, umami, and sour receptors that serve to detect sugars, electrolytes, poisons, amino acids, and spoiled or fermented food, respectively.

01:09:37 Receptors on our tongue can sense fat, which is important for the function of our nervous system and organs, and the ability to sense fat in our mouth is critical for our overall chemical sensing apparatus.

01:16:24 Developing a sensitive and nuanced palate is possible through top-down mechanisms, and the taste preferences and sensitivities of different animals can vary greatly, with carnivorous animals having a heightened ability to detect savory flavors and herbivores having a heightened ability to detect sweet flavors, which may explain why people who eat more meat tend to crave umami-like foods, while those who eat a more plant-based diet tend to have a heightened desire for sweet foods.

01:23:32 Taste receptors are not only found on the tongue, but also in other cells and tissues throughout the body, including the gut, digestive system, and reproductive organs, suggesting a possible connection between the sensory experience of food and the reproductive axis.

01:31:00 The relationship between smell and taste is very close, as the combination of odor and taste receptors being activated triggers the activation of multiple brain areas associated with taste and related behaviors, such as leaning towards or away from certain tastes.

01:37:36 Our entire experience of taste is dependent on how we experience it at the level of the tongue, and an experiment using miracle fruit can completely change our perception of any food by revealing how much the sense of sweetness contributes to our experience of a particular flavor.

01:44:36 Chemical signaling between humans, including the ability to detect and discriminate scents, exists and is influenced by hormones, but the identification of specific pheromones is still unclear.

01:51:04 We actively evaluate the chemicals on people's breath and skin, including pheromones and odors, as a way to assess their hormone status and make judgments about them.