Hormones & Instincts: Hunger, Aggression & Parenting Behavior | Jonny Kohl | 262

Wide release date: November 7, 2025.

Episode Summary: Dr. Johannes Kohl explains instinctive behaviors in mice, focusing on how hunger and estrous cycle hormones interact in the hypothalamus to toggle between parental care and pup-directed aggression in virgin females; he also details how pregnancy hormones rewire the medial preoptic area for robust maternal behavior before birth, revealing multi-timescale neural integration of internal states.

About the guest: Jonny Kohl, PhD is a group leader at the Francis Crick Institute in London, heading the State-Dependent Neural Processing Lab.

Discussion Points:

• Instincts are pre-wired, robust yet modifiable by experience and states like hunger.

• AGRP “hunger neurons” in the hypothalamus regulate hunger state and respond to environmental cues related to food.

• Hunger regulates parental care neurons in medial preoptic area (MPOA) via inhibitory peptides.

• Estrous cycle (4-5 days) in mice comes with fluctuations in estradiol & progesterone; their ratio, not absolute levels, gates aggression probability.

• Hormone ratio sensed in MPOA neurons via nuclear receptors altering gene expression of HCN ion channels, changing excitability.

• Pregnancy (20 days) boosts parental circuits in MPOA via hormone surges before pregnancy ends, enabling instant care at birth.

• Hormone fluctuations enable adult brain plasticity.

• Humans disrupt natural cycles (e.g., hormonal contraceptives, GLP-1 drugs) that have broad, poorly understood brain effects.

Reference Paper:

• Study: Integration of hunger and hormonal state gates infant-directed aggression

Related Episode:

• M&M 89: Neuroscience of Aggression, Sex, Behavior, Hormones, Emotion & Consciousness | David Anderson

*Not medical advice.

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• Episode transcript below.

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Episode Chapters:

00:00:00 Intro

00:03:26 Dr. Kohl Intro
00:08:19 Defining Behavioral State
00:13:08 Hunger Circuitry & AGRP Neurons
00:18:16 Hunger vs Parental Behavior in Virgin Females
00:20:44 Estrous Cycle & Hormone Fluctuations
00:28:54 Hunger-Hormone Integration in MPOA
00:35:51 Ion Channels & Multi-Timescale Signaling
00:43:12 Pregnancy Rewires Parental Circuits
00:48:55 Balancing Hunger & Maternal Care
00:53:28 Hormonal Contraception & Brain Effects
00:57:16 Future Directions & Closing

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Full AI-generated transcript below. Beware of typos & mistranslations!