Mind & Matter
Whether food, drugs or ideas, what you consume influences who you become. Learn directly from the best scientists & thinkers alive today about how your mind-body reacts to what you feed it.
The weekly M&M podcast features conversations with the most interesting scientists, thinkers, and technology entrepreneurs alive today.
Not medical advice.
At M&M, we are interested in trying to figure out how things work, not affirming our existing beliefs. We prefer consulting primary rather than secondary sources and independent rather than institutional voices. If we encounter uncomfortable truths or the evidence suggests unfashionable ideas may be valid, so be it.
As the host, my aim is to help you better understand how the body & mind work by curating & synthesizing information in a way that yields science-based insights that you can choose to use or disregard in your own life. Taking ownership of your health starts with taking ownership of your information diet.
I am motivated to connect the dots and distill general principles from what I learn, preferring to ask questions and play devil’s advocate to debating or incessantly pushing my own viewpoint.
My beliefs:
- Taking ownership of your health starts with taking ownership of your information diet.
- All knowledge is provisional and we must work hard to prevent ourselves from becoming attached to our favorite ideas & preferred conclusions.
- Wisdom comes from an iterative, trial-and-error process of learning and unlearning. Letting go of pre-conceived notions can be painful, but pain is information.
Sometimes modern discoveries teach us we must unlearn received wisdom. Other times, modern information overload & historical chauvinism cause us to forget ancient wisdom which stills applies. The framework for learning that I embody is inspired by three Ancient Greek maxims inscribed in the Temple of Apollo at Delphi:
- “Γνῶθι σεαυτόν” (Know thyself)
- “Μηδὲν ἄγαν” (Nothing in excess)
- “Ἐγγύα πάρα δ Ἄτα” (Certainty brings insanity)
Mind & Matter
Hormones & Instincts: Hunger, Aggression & Parenting Behavior | Jonny Kohl | 262
How internal states like hunger and hormones shape instinctive behaviors, particularly parental care
Episode Summary: Dr. Johannes Kohl explains instinctive behaviors in mammals, emphasizing how states like hunger and hormonal cycles modulate actions such as parental care; they discuss hypothalamic circuits, hormone integration, and pregnancy-induced brain changes, highlighting the balance between motivations like feeding and nurturing offspring.
About the guest: Jonny Kohl, PhD heads the State-Dependent Neural Processing Lab at the Francis Crick Institute in London.
Discussion Points:
- Instinctive behaviors: Pre-wired actions like escaping predators or parental care enable survival without learning, yet remain modifiable by experience and internal states.
- Internal states: Defined as slowly changing conditions (minutes to weeks) like hunger or hormonal fluctuations that influence brain processing & behavior prioritization.
- Hunger regulation: Hypothalamic AGRP neurons detect caloric deficits, creating motivational discomfort relieved by food anticipation, operating on multiple timescales via neurotransmitters & peptides.
- Parental care: Virgin mice show variable pup-directed behaviors; hunger increases aggression, modulated by estrous cycle hormone ratios (estradiol/progesterone).
- Hormone-brain interactions: Steroid hormones like estradiol and progesterone diffuse into the brain, altering gene expression, neuronal excitability, and circuit plasticity over short and long timescales.
- Pregnancy adaptations: Late pregnancy rewires MPOA circuits via surging hormones, preparing robust maternal behavior before birth (anticipatory brain plasticity).
Practical Takeaways:
- Recognize hunger’s impact: Mild food deprivation can heighten irritability or aggression, which can affect social interactions.
- Consider hormonal influences: Cyclical hormone changes affect mood and motivation; tracking cycles may help predict and manage behavioral shifts.
- Prioritize self-care in parenting: Sleep and nutrition deficits mimic hunger states, potentially reducing patience; ensure rest and meals to support nurturing behaviors.
- Question chronic hormone use: Long-term interventions like birth control or testosterone can alter brain function; weigh benefits against potential side effects.
Reference Paper:
- Study: Integration of hunger and hormonal state gates infant-directed aggression
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