Neuroscientists Discover Why Moms Take Risks to Protect Their Infants

Elevated Pup Retrieval

The elevated pup-retrieval test was used to assess the willingness of mice to care for infants in risky/dangerous situations. See the accompanying video for the results. Credit: RIKEN

It might seem like a given that mothers take extra risks to protect their children, but have you ever wondered why? A new study led by Kumi Kuroda at the RIKEN Center for Brain Science (CBS) in Japan shows that in mice, this and other nurturing behaviors are driven in part by neurons in a small part of the forebrain that contain a protein called the calcitonin receptor. The study was published in Cell Reports.

Many simple behaviors, such as eating and drinking, are driven by different parts of the brain’s hypothalamus. The new study focused on identifying the part that drives a much more complicated behavior: caring for infants. As Kuroda explains, “we were able to narrow down the brain cells necessary for parental and non-parental care in mice to a subset of neurons in the central MPOA region that contain the calcitonin receptor.”

The team’s previous research pointed to the central MPOA (cMPOA) region of the hypothalamus as the hub of nurturing behavior. This part of the brain contains more than seven different kinds of neurons, and the goal of the new study was to find a marker for the ones which are the most important for nurturing. The researchers visualized 20 candidate genes in the cMPOA of nurturing mice together with a marker for active neurons. Double labeling was highest for the calcitonin receptor gene, making it the most likely marker for nurturing-related neurons.

A virgin female mouse and a mother mouse are tested on the elevated pup-retrieval maze. As in the example, only mother mice retrieved the pups in this situation (although virgin mice did so willingly in the home cage when it was not dangerous). When the calcitonin receptor was downregulated, mothers also hesitated to take the risk. Credit: RIKEN

Next, the researchers examined these neurons in detail. There were three major findings. First, the number of cMPOA neurons with the calcitonin receptor was higher in post-partum mothers than in virgin females, males, or fathers. Second, incoming and outgoing connections to these neurons from other parts of the brain changed in females after they gave birth. Third, silencing these neurons completely disrupted nurturing behavior. Nurturing behaviors in mice include nest building, hovering over pups in the nest, and picking pups up and bringing them back to the nest — termed pup retrieval.

After the critical neurons were silenced, virgin females left pups scattered around the cage, even after mating and birthing their own pups. Other behaviors such as nursing and nest building were also affected, and the mothers acted overall as if they had little motivation for nurturing behavior. As a result, many pups could not survive without intervention.

After establishing that cMPOA neurons expressing the calcitonin receptor are necessary for nurturing, the researchers hypothesized that the receptor itself has a special function in generating the enhanced motivation for nurturing observed in mothers. To test this hypothesis, the team devised a new pup retrieval test. Instead of placing the pups around the edges of their home cage, they placed them on an elevated maze. Being out in the arms of the elevated maze is a little unpleasant and scary for mice.

Virgin females that would retrieve pups in the cage refused to do it in the elevated maze. In contrast, mother mice always retrieved the pups, showing that their drive to nurture was greater. However, when calcitonin receptor levels were reduced by about half, even mother mice hesitated and took much longer to complete the retrievals.

“Parents, both human and animal, must choose to sacrifice one behavior for another in order to care for their children,” says Kuroda. “We found that upregulation of the calcitonin receptor is like a push in the brain that motivates mice to care for their pups, suppressing their self-interest and tendency to avoid risky and unpleasant situations.”

“The next step is to examine calcitonin receptor-expressing cMPOA neuron’s role in the nurturing behavior of non-human primates, which should be more similar to what happens in humans.”

Reference: “Calcitonin receptor signaling in the medial preoptic area enables risk-taking maternal care” by Chihiro Yoshihara, Kenichi Tokita, Teppo Maruyama, Misato Kaneko, Yousuke Tsuneoka, Kansai Fukumitsu, Eri Miyazawa, Kazutaka Shinozuka, Arthur J. Huang, Katsuhiko Nishimori, Thomas J. McHugh, Minoru Tanaka, Shigeyoshi Itohara, Kazushige Touhara, Kazunari Miyamichi and Kumi O. Kuroda, 1 June 2021, Cell Reports.
DOI: 10.1016/j.celrep.2021.109204

23 Comments on "Neuroscientists Discover Why Moms Take Risks to Protect Their Infants"

  1. Gregory Phillips | June 3, 2021 at 5:34 am | Reply

    you stupid evolutionists – they were CREATED that way!

  2. This seems like a possibility for one of two drugs: something to treat post-partum psychosis, or a drug to enhance the nurture center of all males so that society can improve globally.

    • Ladybugs 4ever | June 9, 2021 at 5:48 am | Reply

      Sorry meant to reply to you but just posted normal way. It is long but I think you might like my replies. Please read if you have a moment and ignore rude trolls. Thx

  3. Claudia Thacker | June 7, 2021 at 8:19 am | Reply

    Wasted money to torture animals!

  4. You can reasonably argue any mother that is unwilling to care for her children will not have surviving offspring. Evolution applies.

  5. This explains why drug abusing and alcoholic mother’s become less nurturing.. also, proves that no one is as nurturing as a Mother. A biological WOMAN.. Sorry fellows. We’ve always known that a mother will fight to the death for their children and that includes in the animal kingdom.

  6. Darla correlation does not equal causation you somehow took an extremely well thought-out and researched topic and somehow simplified it to Facebook mom terms gtfo

  7. Okay LM so you’re a complete dumb*ss The entire reason why women have these genes to begin with is a product of evolution and help to survive and here you’re saying let’s take sh*t like “estrogen” and make guys feel more sh*t like we’re the problem… Maybe by nature there’s just different GENDER ROLES, men don’t need to become more caring I’ve seen plenty of super dads ones that would take way more risk than an average woman if you can simplify every living things behavior into a generalized personality then you’re not going to understand people very well, man or woman everybody’s personality is ddifferent. So you can’t say it man needs to become more caring it’s a societal problem people don’t care not a certain gender in particular

  8. Duh! God made a woman to have these motherly instincts to protect their young! Even female animals were created in that same manner!

  9. @bandit – plenty of human babies thrown in a trash can have survived in the last 50 years.

  10. Why don’t you leave the poor animals alone? Use human’s for the test.

  11. This isn’t something I usually read but I found this quite interesting. I wasn’t going to comment but I felt bad that the only comments you had were attacking you for the texting when all you did was write a story for it.

  12. Is this a joke…

  13. Charlene Williams | June 9, 2021 at 4:36 am | Reply

    Poor mommy mice. It’s called love, genuine LOVE!!!

  14. Ladybugs 4ever | June 9, 2021 at 5:45 am | Reply

    LM that is interesting idea on second comment, but seeing as how men still run the world basically, that is not likely but it would be amazing to have less abandoned kids and wives by men who are selfish and see no need to protect or care for them. That trauma ruins kids and leads to lifelong issues that spill i to other generations. On the flip, I know some incredibly protective dads that are former military with traumatic brain injury and wonder if the injury impacted this receptor thing more than the PTSD or injury itself? They are not helicopter parents at all but would do extreme or risky things to save kids no second thought. Next is wondering why giving birth would increase this? Is it chemical or due to the birth trauma? More people should be given this boost to improve society but my guess is the powers that be will actually suppress it in certain groups if they have not already been doing so to reduce populations and make the world more narcissistic and our kids less protected and cared for. Lots if predators in this world and in powerful places. I would think a good use would be to require child caregivers, adoptive parents, foster parents and the like a mandatory amount the first year they adopt at least and continued supply for caregivers and orphanage workers so they take better care of the kids ans the kids thrive better. Maybe the natural amounts adults have can be measured and if sufficient and higher on empathy scale no need for it but if low levels of this calcitonin and low levels of empathy then likely to be a negligent parent so either denied the job, the adoption unless you choose to boost your abilities. That would be a good use after a sufficient amount of research. I also wonder if this has correlation to why some moms get like superhuman strength when like lifting a car to save their kids? Maybe the ones with high levels interact with adrenaline in an I usual way to give them brief superhuman ability? Very cool research and if my last question is true then I see this research being used for military and first responders as non steroid performance enhancers. Power but without rage and volatility is worth billions.

  15. Conan Vidarman | June 9, 2021 at 6:25 am | Reply

    Where is the research and proof that father mice would not do the same as mother mice?
    I saw an accusation, but I did not see anything to back the claim.

  16. Hey esteemed author, your article mentions “more than seven types of neurons,” however there are not currently 7 types of neurons identified. You are spreading fake news, even if inadvertently.

    Source: My fiance in who is currently in grad school who has a BS in Neuroscience..and google, they are in agreement. Good day!

    • Mike O'Neill | June 9, 2021 at 7:58 am | Reply

      Thanks for your message. There are different classification systems for neurons. The simplest has fewer and the more complex systems have more.

      At the most simple, there are three types: motor neurons, sensory neurons, and interneurons. Yet if you Google “10,000 specific types of neurons in the human brain” you will see there are many different kinds.

      I’m not sure what classification system the author was considering, but that detail is beyond the scope of this article. (I should also point out that they are from Japan, in case that has any bearing.)

  17. Aloof Alcoholic | June 9, 2021 at 7:52 am | Reply

    Ignorant ass comments🤣 but Thats interesting about the potential for calcitonin to treat post partum psycosis uh i mean depression

  18. Would be an interesting study in parents v step/foster/adoptive parents as well.

  19. William McDaniel | June 9, 2021 at 12:29 pm | Reply

    Interesting observation that reminded me of an incident that happened at our bird feeding suit feeder station a few days ago. The Starlings usually dominate around the feeder except when the Red-bellied Zebra-backed Woodpeckers want to feed. When the Woodpeckers leave then it’s wartime among the Thrashers, Catbirds, Redheaded Woodpeckers, Downey and Hairy Woodpeckers and others. A few days ago a Thrasher managed to get to the suet feeder first with her hungry baby in tow. I was amazed to see the Starlings back off while she feed her baby. When a Starling tried to move in the Thrasher would just turn and give him that look and the Starling would back off. I deduced that a mother with her baby was more defensive and the Starling seemed to know that.

  20. Do these idiots get paid for this Democrats throwing money in garbage Because 30 trillion in debt really isn’t that bad

  21. This in: scientists torture mothers for obvious outcomes

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