[00:00:00] Dr Renee White: Knowledge is power, and we are all about empowering the mamas of the world. In each episode, we will unravel and interpret the latest research and evidence-based practices for pregnancy, postpartum, and motherhood. [00:00:15] As mums and researchers ourselves, we have experienced firsthand the overwhelming complexity of information myths and those classic old wives tales. I'm Dr. Renee White, and this is The [00:00:30] Science of Motherhood.

[00:00:30] Dr Renee White: Hello and welcome to episode 205. This is The Science of Motherhood, and I'm your host, Dr. Renee White. In today's episode, we are exploring the fascinating science of how your brain and [00:00:45] your baby's brain literally synchronize during interaction.

[00:00:50] Dr Renee White: Now, have you ever wondered what's actually happening in your brain and your baby's brain when you are gazing into each other's eyes, [00:01:00] smiling and cooing together?

[00:01:02] Dr Renee White: I have mentioned this so many times, and in particular it was in an episode with Dr. Greer Kirschenbaum. I said, wouldn't it be fascinating to have a device that you could [00:01:15] have with mother and baby to see all the amazing neuro kind of synapses and hormones going. This is kind of on the similar vein, so maybe you've noticed, uh, how your baby [00:01:30] seems to light up when you're feeling happy and engaged.

[00:01:33] Dr Renee White: The. Becomes a bit more withdrawn when you're stressed or flat. Now, if you are curious about the invisible connection happening between you and your little one, and [00:01:45] why the emotional quality of your interaction matters so much, you are not alone. And so today's episode is absolutely for you. So today I'm gonna be diving into a groundbreaking study that used [00:02:00] dual brain imaging to watch mothers and infants brains work together in real time.

[00:02:05] Dr Renee White: So you are going to discover how positive emotions literally strengthen the connection between your two brains, [00:02:15] creating what researchers are calling a mega network that supports optimal learning. And definitely stick around for when I explain how this research reveals one mechanism through which maternal depression might affect infant [00:02:30] development.

[00:02:30] Dr Renee White: It is a moment that completely reframes why supporting maternal mental health is so crucial. This episode is proudly supported by Fill Your Cup, Australia's first doula village. If you are [00:02:45] pregnant or have a new baby, congratulations. We have doulas ready to look after you, nurture you, nourish you all across Melbourne, Geelong, sydney, Newcastle, Brisbane, gold [00:03:00] Coast, Hobart, and Perth. Alright, let's dive in.

[00:03:05] Dr Renee White: Now before we get into the study itself, let's talk about why this research is so important. Now, we know that social [00:03:15] interaction is crucial for infant development. Babies learn almost everything through their relationships, whether it be language, emotions, how to regulate their feelings, and even how to think.

[00:03:28] Dr Renee White: But until [00:03:30] recently, we've mostly studied this by watching behavior, looking at what babies and parents do and, and how they respond to each other, and how long. They essentially look at other things. What we haven't been [00:03:45] able to see is what's happening on the inside, what's happening inside their brains during these interactions.

[00:03:52] Dr Renee White: Now this study led by, um, Vicki Leong, um, at the University of Cambridge in the uk used a [00:04:00] technique called dual, EEG. And I'm gonna have a go at this that's Electroencephalography. And so that essentially means to record brain [00:04:15] activity from both the mother and infant simultaneously while they interacted naturally as naturally as you can with like a big cap on your head full of electrodes.

[00:04:26] Dr Renee White: So essentially think about it [00:04:30] like a, like recording, two instruments playing together. To see how they harmonize. Now, the researchers were particularly interested in something called interpersonal neural connectivity, and [00:04:45] basically what that means is when two people's brainwaves start to sink up during interaction.

[00:04:52] Dr Renee White: Previous research had shown this happens between adults, but very little work had looked at it in [00:05:00] that parent infant pairs and critically no one had examined how the emotional quality of the interaction, whether it be positive or negative, affects this brain to brain connection. [00:05:15] Okay, let me walk you through how they did this study.

[00:05:19] Dr Renee White: Now, the researchers recruited 15 mother infant pairs. The infants were around 10 months old, which is a really interesting age because [00:05:30] babies are becoming more socially sophisticated around that age. They're starting to use social referencing to learn about the world, and their brains are incredibly plastic and responsive to experience.

[00:05:44] Dr Renee White: [00:05:45] Now, both mum and Bub wore those EEG. Caps now these are like, just think of it like, like a swimming cap, and it's covered in electrodes that essentially measure electrical activity in the brain. And they [00:06:00] focused on 16 channels covering frontal, central and parital brain regions. And these are the areas involved in attention, emotion processing and social [00:06:15] cognition.

[00:06:15] Dr Renee White: And here's where it gets interesting. Now, the mums were asked to perform what's called a social referencing task. Now, they showed their babies pairs of novel objects, things the babies had never seen [00:06:30] before, and they modeled either positive or negative emotions towards each object.

[00:06:36] Dr Renee White: So for the positive condition mums were asked to smile, use an upbeat, [00:06:45] enthusiastic tone, make lots of eye contact and say things like, I like this one. For the negative conditions they'd frown, use more flat or disapproving tones, um, less eye [00:07:00] contact and say things like, I don't like this. I don't like this one.

[00:07:04] Dr Renee White: The researchers recorded the brain activity from both mum and bub throughout these interactions, and then they analyzed not just the strength of the connection between the two [00:07:15] brains, but the structure and topology of that connection. And so essentially how the information was flowing within each brain and between the two brains as a network, they [00:07:30] looked at two types of connectivity measures.

[00:07:32] Dr Renee White: So the first is PLV, so phase locking value, which measures, um, a synchronization without direction. And then they measured something called [00:07:45] PDC, which is partial directed coherence. And that, um, shows the direction of influence. So, is mum influencing baby more or vice versa? [00:08:00] And they focus particularly on, you know, six to nine hertz frequency band.

[00:08:05] Dr Renee White: Now this is the infant alpha range and it's strongly associated with emotional processing and social cognition in [00:08:15] both infants and adults. So let's get to the key findings. What did they find? The results are really, really striking.

[00:08:24] Dr Renee White: Finding number one, positive emotions strengthen [00:08:30] the parent infant neural network. So when mums expressed positive emotions, their inter brain network showed significantly higher connectivity, strength and integration compared to when mothers expressed [00:08:45] negative emotions.

[00:08:46] Dr Renee White: So using multiple measures, density, strength, and something called divisibility. So the researchers consistently found that parent and baby brains were working together. More [00:09:00] cohesively during positive interactions.

[00:09:02] Dr Renee White: So think of it like this. When you are happy and warm and engaged with your baby, your brains are off essentially like operating more like a unified system, [00:09:15] sharing information efficiently. So when the emotional tone is negative, that connection really weakens.

[00:09:25] Dr Renee White: Alright, finding number two, direction [00:09:30] matters. So mothers lead during positive emotions, so using that directed connectivity measure, they found that mothers had a stronger influence on their baby's brain during positive [00:09:45] emotional states.

[00:09:46] Dr Renee White: So the information flow from mother to infant was significantly higher when mums were expressing positive emotions. And interestingly, during negative emotions, the pattern [00:10:00] flipped somewhat. So infants showed relatively stronger influence on that kind of dyadic network, and the researchers suggest this might be because babies increase their attention seeking behavior and visual [00:10:15] scanning when they perceive negative emotions from their mum.

[00:10:21] Dr Renee White: Finding number three, minimal changes in individual brain networks. So here was something very [00:10:30] surprising while the between brain connectivity changed dramatically with emotional kind of valence. The within brain networks, the connectivity patterns inside each person's brain, [00:10:45] within the mum and within the bub, showed relatively few differences between positive and negative conditions.

[00:10:52] Dr Renee White: So for for the infants. These were essentially, you know, no differences in their own brain network [00:11:00] organization between conditions for mothers. There were some subtle changes suggesting more integrated processing during positive emotions. But these were much smaller than the inter brain effects. [00:11:15] And what this tells us is something really important and that is that the emotional quality of the interaction affects how two brains connect with each other even more [00:11:30] than it affects what's happening inside each individual brain.

[00:11:35] Dr Renee White: And finding number four, the frequency absolutely matters. So the strongest effect were definitely in the six to nine hertz range that that [00:11:45] infant alpha band and this frequency is associated with internally controlled attention and emotion processing.

[00:11:53] Dr Renee White: So when parents and babies sync up in this frequency range during positive interactions, it [00:12:00] may create an optimal state for learning and information transfer. So, what does this all mean for brain development? Now, the infant brain, as I said, is [00:12:15] incredibly plastic. You know, it's changing and forming new connections based on experience every second of the day.

[00:12:21] Dr Renee White: So during the first year, babies are in a critical period for social and emotional development. Their brains are [00:12:30] literally being shaped by their interactions with caregivers. So when you and your baby achieve strong neural synchrony, so when your brains are well connected, your baby is more receptive and ready to [00:12:45] learn, and the researchers note that this connected state facilitates efficient information sharing.

[00:12:52] Dr Renee White: So your, your baby's brain is essentially borrowing processing power from your more [00:13:00] mature brain okay. So if you think about it like this, when you're in a positive emotional state together, so lots of eye contact, smiling, responsive interaction.

[00:13:13] Dr Renee White: You are creating the neural [00:13:15] conditions for optimal learning, so your baby's brainwaves are literally aligning with yours, and in that aligned state, information flows more easily. So this has [00:13:30] implications for every domain of learning, language acquisition, emotional regulation, social understanding, even cognitive development.

[00:13:39] Dr Renee White: So when babies spend more time in this positively synchronized [00:13:45] state with their caregivers, their brains have more opportunities to build the connections that support all these skills. And so conversely, when Synchrony is disrupted, which can happen with things like [00:14:00] maternal depression, stress, and other challenges in our lives, babies have, you know, they may have fewer of these optimal learning opportunities.

[00:14:10] Dr Renee White: So I guess that does bring us to that maternal depression [00:14:15] connection, which is an important clinical implication of this research. And the researchers have explicitly discussed how these findings relate to maternal depression. And when mothers experience [00:14:30] depression, several things change in their interaction style.

[00:14:34] Dr Renee White: The first thing is generally that their speech often becomes flatter in tone. They may use less eye contact. They're less responsive when their [00:14:45] baby tries to get their attention. And, you know, in, in instances, you know, they're spending less time in positive emotional states. Now all of these changes would be expected to weaken the neural connection between mother [00:15:00] and baby.

[00:15:00] Dr Renee White: And as we've just discussed, that weakened connection means fewer opportunities for optimal information sharing and learning. Now, the caveat always is, you know, this doesn't mean that babies [00:15:15] of depressed mothers can't learn or develop. Well, that's not what we're saying here. Um, but it does suggest one mechanism through which maternal depression might affect infant development.

[00:15:26] Dr Renee White: And it's also a reminder of why treating maternal mental health [00:15:30] is so crucial, not just for mother's wellbeing, but for supporting optimal infant development. So, if you are experiencing depression, this isn't about guilt or blame. Depression is a medical [00:15:45] condition. These findings actually underscore why getting treatment and support is so important, not just for you, but for establishing those strong neural connections with your bubby.

[00:15:56] Dr Renee White: So what are the takeaways? What can we actually do with this [00:16:00] information? Well, the first thing is prioritize positive emotional interactions. So the quality of emotional engagement really matters. So when you are interacting with your baby, try to be present, warm, [00:16:15] genuinely positive. This doesn't mean that you have to be happy all the time.

[00:16:20] Dr Renee White: That's, that's, you know, neither realistic nor necessary. But during your focused interaction times, bringing that positive emotion helps [00:16:30] create that strong neural connection. Second thing I would probably say is that face-to-face time is really valuable. So this study involved direct face-to-face interactions with lots of [00:16:45] eye contact.

[00:16:45] Dr Renee White: So while babies can learn from many types of experiences, these direct social interactions with caregivers where you are looking at each other, responding to each other, appears to be particularly powerful for [00:17:00] brain synchronization. Third, your emotional state influences more than you might think. So we often think about how our emotions affect our own experience, but what this [00:17:15] research shows, they're also affecting the neural state of our babies.

[00:17:19] Dr Renee White: So when you are feeling good and engaged and emotionally available, you're literally changing your baby's brain state in what that, you know, in, in ways that really [00:17:30] support their learning. Number four, this big one. It's not about perfection like really remember that this study compared positive versus negative emotional modeling, but real life isn't all one [00:17:45] or the other okay.

[00:17:46] Dr Renee White: So babies also need to experience some range of emotions. The key insight is that spending significant time in positive connected states supports optimal development. [00:18:00] Finally, like I've already said, support for mental health, particularly for mamas, is crucial. So if you are struggling with depression or anxiety or other mental health challenges, seeking support isn't just about you.

[00:18:12] Dr Renee White: It's about, you know, supporting [00:18:15] your ability to establish these strong neural connections with your baby. And if, if you are concerned about this, then we have got a range of resources listed in the show notes that you can connect with.

[00:18:27] Dr Renee White: Before we wrap up, let's always acknowledge the [00:18:30] limitations of these studies. That's what we do here at the Science of Motherhood. There's always limitations to every study. First one, the sample size. It was relatively small, you know, it was 15 mother infant pairs. So while the effect was strong and [00:18:45] consistent, we'd want to see this replicated in larger, more diverse samples.

[00:18:49] Dr Renee White: The second, this was somewhat artificial task, right. So mothers were asked to deliberately model positive or negative emotions toward novel objects. [00:19:00] So I guess while this gave the researchers good experimental control, it's not quite the same as naturalistic spontaneous interaction. So future research, I guess, looking at natural emotional [00:19:15] variations would be really valuable.

[00:19:17] Dr Renee White: The third and the researchers had to be very careful about movement artifacts and muscle activity contaminating the EEG signals. So this was always a challenge with infant research, and it's [00:19:30] one reason why they focused on that six to nine hertz range, which is less affected by these artifacts.

[00:19:37] Dr Renee White: Finally, this was a snapshot in time. So, you know, with 10 month olds, that's quite a narrow window. We don't know [00:19:45] how these patterns of neural synchrony develop across the first year or how they relate to longer term outcomes for children all right.

[00:19:54] Dr Renee White: So I guess, you know, this research essentially reveals something [00:20:00] remarkable when you interact with your baby in a warm, positive way. Your brains don't just respond independently. They synchronize creating a unified network that supports information sharing and learning. So [00:20:15] the emotional quality of your interaction literally changes how your two brains connect with one another.

[00:20:22] Dr Renee White: For parents, this underscores the importance of those moments of positive connection, the smiling, the eye contact, as I said, the warm [00:20:30] engagement for clinicians. It highlights why supporting maternal mental health is so crucial, not just for mamas, but for Bubbas as well, and for all of us. It reveals something really beautiful about human connection. We are [00:20:45] wired to literally sync up with the people that we love.

[00:20:49] Dr Renee White: So the next time you are gazing into your baby's eyes and you are smiling at each other, remember this, your brains are dancing together, creating the neural [00:21:00] foundation for all the learning and development to come. All right, until next week, see you later.

[00:21:08] Dr Renee White: If you loved this episode, please hit the subscribe button and leave a review. If you [00:21:15] know someone out there who would also love to listen to this episode, please hit the share button so they can benefit from it as well.

[00:21:23] Dr Renee White: You've just listened to another episode of The Science of Motherhood proudly presented by Fill Your Cup, [00:21:30] Australia's first doula village. Head to our website I fill your cup.com to learn more about our birth and postpartum doula offerings where every mother we pledge to be the steady hand that guides you back to yourself. [00:21:45] Ensuring you feel nurtured, informed, and empowered so you can fully embrace the joy of motherhood with confidence. Until next time, bye.