That Neuroscience Guy - Season 1 Finale - The Neuroscience of Love

Episode Date: June 27, 2021

Love is an essential part of the human experience, just as much as heartbreak is. In the season 1 finale of That Neuroscience Guy, I discuss the neuroscience of how we experience love, and the lack thereof. 

Hi, my name is Olof Kregolsen, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Have you ever wondered why we fall in love? Ever wondered why it hurts so much when we break up? Ever wondered about the feelings that we feel for our parents or our children? Well, on today's episode, I'm going to talk about the neuroscience of love. At the simplest level, our brain and some of the midbrain structures create a desire to reproduce. It's built into us. It's innate and it's controlled by these midbrain structures like the hypothalamus.

If you recall from earlier episodes, the hypothalamus is a midbrain structure that regulates the autonomic nervous system. And if you recall, the autonomic nervous system is comprised of the sympathetic and the parasympathetic nervous systems. And these control primary body functions. Your breathing, for instance, your heart rate, speeding up your heart rate, slowing it down, making you sweat more, making you sweat less. So the ANS controls these systems. And say you see your significant other, and if your heart begins to beat a little bit faster or you begin to breathe a bit differently,

well, this is the system that controls that. And it's important to know this is largely out of your control. These physiological reactions, they're hardwired. It's your brain just signaling to you that you're a little bit nervous or you're a little bit excited and you sweat a little bit more. And that's just the brain responding to higher level structures with this lower level system. It's just giving off this signal of attraction.

This is what your body does. So don't feel bad if your heart rate speeds up or you're sweating a little bit when you see that significant other, because that's just your autonomic nervous system doing its job. Now it's a bit more complex than that. We've talked about the amygdala before, a midbrain structure attached to the front of the hippocampus. We know that it plays a role in emotion. We talked about some of the studies earlier in the season. There's just too many of them to discuss,

but basically when you see someone you love, your amygdala responds. It's giving a little bit bigger of a signal. It's a positive emotional response, if you will. This is also true, funnily enough, if you see someone you dislike. The amygdala seems to signal emotion and levels of emotional content and doesn't care as much about the valence, if you will.

What's interesting is there's some cool research on this. Some great work by Helen Fisher showed that when someone breaks up with you, their amygdala has a little bit less activity. It doesn't mean they don't love you. It's just that they decide to break up with you, so the amygdala is a little bit less. And the person being broken up with, well, their amygdala, it's responding even more than usual. So if you've ever been dumped and you've had that longing sensation for your ex, this is your amygdala working on overdrive. And that's why you keep reaching out and doing dumb things. It's because your amygdala is just going on overdrive. Now, I'm not saying it's easier for the other person. Their amygdala is

still firing away and they still have feelings. It's just that because they've made that decision, their brain is trying to regulate the emotional response and there's less activity. decision, their brain is trying to regulate the emotional response, and there's less activity. And when they were in the relationship with you, well, guess what? Their amygdala would have been firing more. So the amygdala is also encoding love, and it's actually what's sending signals to the ANS, that emotional response is helping drive and control those lower-level systems. But of course, as ever, it's more complicated than that. One of my favorite studies in this area is by Samir Zeki and Andres Bartels from University College London. And what they did is they took 17 healthy people, males and females, age 21 to 37,

and they had all reported that they were truly deeply and madly in love with someone. So what they did is they put these people in an fMRI scanner and they viewed pictures of their significant others, the people that they were truly deeply and madly in love with, and they viewed pictures of other people. And what they found is that when they saw someone that they were truly in love with, a whole bunch of brain regions lit up. There was the menial insula, the anterior cingulate cortex, and segments of the dorsal striatum. These are all brain regions that the pattern of activity signals this love, and it would be very hard to pull apart what all of these brain regions are doing. The dorsal striatum, for instance, seems to play a role in reward signals.

That's probably its contribution to what's going on. But it's the pattern of activity. There's this pattern of activity associated with being in love. Another interesting result from their work is they also found brain regions that appeared to deactivate. So when you see that person you're truly in love with, areas like the right prefrontal cortex, the bilateral parietal cortex, and then both the temporal cortices, they actually had less activity during that time. Now, understanding all of those specific brain regions, like I've already said, would be very hard to do. So let's focus on the pattern. Understanding all of those specific brain regions, like I've already said, would be very hard to do. So let's focus on the pattern.

When you're truly, deeply, and madly in love, there's a pattern of brain activity that encodes that feeling. And that's why you feel that way. In follow-up work, Professor Zeki was at it again, and the picture got even more complex. They were focused more on romantic love. And when it was romantic love, they got additional activity. Medial insta, again, the anterior cingulate, hippocampus this time, the subcortex, parts of the stratum, the nucleus accumbens. And that's a really interesting one, that last one, the nucleus accumbens. This is a key part of the brain's reward system.

So part of the romantic love thing is that when you see that person or you're with that person, it's a reward. Your brain is literally going, this is great. If you think back to our podcast on learning, this is how you learn. So you're learning that being with this person is a great thing. Seki has done so much work in this space, and if you like reading academic papers, and this is a topic you like, I would totally recommend them.

In one study, they found that the brain pattern of activation is different for maternal love than for romantic love. In other words, when you see a picture of your mother or you're, you know, with your mother, there is a pattern of brain activity that represents love, but it's different than the pattern of brain activity for romantic love. Now there is overlap. A lot of the same regions are involved, but there are differences. And those differences are what separate out those two different types of love. In other work, they found a very specific part of the brain that seemed to light up

when people were reporting a very extreme level of love. I guess what we'd call the soulmate phenomenon. So again, that additional thing where you're just completely smitten, that's a different pattern of brain activity. And like I said, it's important to realize that the differences in activation are quite small. It's not like it's one side of the brain versus the other. It's mostly the same brain regions, but there's either more activity or it's just a slightly different part of the brain that's nearby. And more recent work by Takahashi and colleagues implicates our old friend, the dopamine system.

If you remember when we talked about reward, we got really into this idea of dopamine and how dopamine responds and conveys these reward signals. In their work, they sort of replicated what Zeki was doing, and they were looking at pictures of people you love versus pictures of people you don't love. And they found that the dopamine system was activated and brain regions that control the dopamine system. So the pattern is complex, right? There's a lot of stuff going on in a lot of different brain regions. And what about the sadness of breaking up?

Well, we talked about emotions in a previous episode, but basically what you're feeling then is your emotional system is on overdrive. But you might have noticed it's largely triggered by conscious thought. Like if someone's ever broken up with you or you've ever broken up with them, you're fine, you're fine, you're fine, you're fine. And then you think about your ex. And next thing you know, the whole emotional system, all these brain regions are just firing like crazy. And this is why they say the no contact rule is a good thing or distracting yourself. Because when you're not thinking about your ex, your emotional system is functioning largely regularly.

How does it end? How do you get over someone, if you will? At the end of the day, your emotional system is functioning largely regularly. How does it end? How do you get over someone, if you will? At the end of the day, your emotional system begins to realize that the stimulus, your partner, is not around. The response begins to diminish with time. And this is why, like I said, most relationship counselors recommend no contact and to remove all reminders of your ex because if you stop thinking about your former partner, then your brain begins to let go for you. The brain regions that were responding before to the stimulus and the stimulus is your partner, they begin to fire a little bit less and eventually they stop firing. Now, let's just summarize this before we wrap it up.

At a low level, those physiological responses that signal love, well, that's the autonomic nervous system and specifically the parasympathetic and the sympathetic nervous systems. And they're responding away. And when there's an emotional response, the amygdala fires, they start to increase your heart rate or make you sweat a little bit more. And I just said the amygdala fires, they start to increase your heart rate or make you sweat a little bit more. And I just said the amygdala. We've talked about the amygdala with emotion. Well, love involves the amygdala, of course, because it's an emotion. So when you're in love, your amygdala is firing away. And if you think of the other stuff we talked about, I'm not going to go through all of those brain regions again. But the take-home message is that there's a pattern of neural activity that is love. So the emotion is represented by this pattern of activity. And that pattern is

slightly different if it's your mother versus your partner. It's slightly different if it's your child versus you, or whether you're romantically in love or it's your soulmate. But that pattern of neural activity across all those brain regions, combined with the amygdala, combined with the autonomic nervous system, well, that's love. Well, that's all for this episode and this season. We're wrapping up season one. Thank you so much for listening. We've had over 6,000 downloads. We're really excited. A special thanks to Mark and Ernest for all the technical support getting us up and running. And a very special shout out to Matt for all his

behind the scenes work, editing and uploading. He's the brains behind the operation. I couldn't have done this without you, buddy. And a very special shout out to someone who I'm not going to mention, who pushed me and pushed me and pushed me. And eventually I did the podcast. I couldn't have done it without you. Now we'll be back for season two in a month or so, and we hope you keep listening. So subscribe if you haven't subscribed already. And once we're back, you'll start getting the updates. We're still making some decisions about season two and what it's going to be about, but we'll keep it as a surprise. My name is Olive Kregolson, and I am that neuroscience guy. See you soon, and thanks for listening.