Marta Porniece

8️⃣
Huge thanks to my amazing students Jessie & Charlotte 🙌
and to Stephen X Zhang & @markandermann.bsky.social from @harvardmed.bsky.social & NYU Center for Neural Science for their guidance in analysis, conceptualization, and making sense of it all.

7️⃣
These findings highlight functional alterations in hypothalamic satiety-promoting neurons and reveal the neural consequences of an obesogenic environment.

6️⃣
💡 Interestingly, switching from NCD → HFD didn’t further impair PVH-MC4R neurons, suggesting resilience once these circuits are established.

5️⃣
Importantly, switching obese mice back to a “healthy” diet partially restored feeding behavior, but not neural activity, showing lasting effects of high-fat diet on brain circuits controlling appetite.

4️⃣
🥬 In lean mice, feeding-evoked responses gradually grow as a meal progresses → signals satiety & meal termination.
🍔 In hig- fat-diet-fed mice, responses start too strong and stay flat, suggesting impaired satiety signal integration.

3️⃣
🧩 We found that PVH-MC4R neurons integrate satiety signals during feeding, but this process becomes disrupted in diet induced obesity and can’t be fully rescued by dietary intervention.

2️⃣
These questions drove us to study how these neurons integrate satiety signals (brain “calorie counting”) and drive motivation to eat. 🍽️

Obesity dysregulates feeding-evoked response dynamics in hypothalamic satiety neurons - Scientific Reports Scientific Reports - Obesity dysregulates feeding-evoked response dynamics in hypothalamic satiety neurons

1️⃣
🥳 Thrilled to share that my postdoc work has finally hit the press!
www.nature.com/articles/s41...

When we started, we didn’t really know what PVH-MC4R neurons do in obesity.
Are they still signaling or “dead”? (e.g., does the chronically high leptin alter α-MSH–MC4R signaling?)
🧵👇

A food-sensitive olfactory circuit drives anticipatory satiety - Nature Metabolism The authors describe a sensory circuit involving the medial septum (MS), where MS glutamatergic neurons integrate food odours to prime satiety and regulate nutrient intake.

Exciting news from @sophiesteculorum.bsky.social Lab!🤓

👃🧠 Smelling food primes your brain for satiety.
Find out more in 🧵 or under 🔗 www.nature.com/articles/s42...

Congrats to @sophiesteculorum.bsky.social , first author @janice-bulk.bsky.social and all contributing authors!

Slow-Timescale Regulation of Dopamine Release and Mating Drive over Days The rise and fall of motivational states may take place over timescales as long as many days. We used mouse mating behavior to model how the brain orchestrates slow-timescale changes in motivation. Ma...

I am excited to share our preprint on how hypothalamic dopamine neurons govern slow changes in motivation over days! Below are our findings:

www.biorxiv.org/content/10.1...

🙏 Huge thanks to our fantastic co-authors, especially Charlotte & Jessica, for their incredible help. Grateful to Stephen & @markandermann.bsky.social for their key contributions to experimental design and writing. Thanks to Maria Lehtinen for postdoc guidance and Andermann Lab for their insights.

🧬 Our data suggest that in obesity, feeding responses in PVHMC4R neurons fail to "reset" between meals, possibly due to persistently high leptin and disrupted AgRP/α-MSH signaling.
🎯Future work should assess peptide transmission onto PVHMC4R neurons to pinpoint mechanisms and refine interventions.

🔄 Can switching from a high-fat to a healthy diet reverse brain changes in obesity?

Switching high-fat-diet fed mice to normal chow diet partially restored early-meal PVHMC4R responses and the licking vigor, but the gradual increase in responses was blunted.

⚖️ The strengthened responses were not driven by reduced motivation to consume palatable food - they consumed less despite food restriction and caloric matching to controls.
🧠 This behavioral suppression points to premature satiation rather than motivation deficits.

🍽️ In lean mice, feeding-related responses in PVH-MC4R neurons gradually strengthen during a meal, reflecting growing satiety.
🧠 In mice fed a HFD for many weeks, responses are already strong at meal onset and don’t further increase over the meal, suggesting a disruption in encoding of satiety state.

Obesity dysregulates feeding-evoked response dynamics in hypothalamic satiety neurons Melanocortin-4 receptor-expressing neurons in the paraventricular nucleus of the hypothalamus (PVHMC4R) integrate hunger-promoting and hunger-suppressing signals to regulate satiety. Food consumption-...

🚨 Paper alert!
📣 We found abnormal feeding-related neural responses in satiety-promoting, MC4R-expressing neurons in the mouse paraventricular hypothalamus (PVH-MC4R) following diet-induced obesity. www.biorxiv.org/cgi/content/... ​​ #obesity #feedingbehaviour #obesityresearch #neuroscience