Thinking back to fifth grade field trips, the long lines, the sweltering hot Louisiana sun, and the teachers who thought that the visit would be the pinnacle of fifth grade achievement, I became accustomed to disliking trips to public places like zoos, museums, aquariums, etc. That being said, I never would have imagined finding myself paying 16.50 euros to go to a zoo here in Paris—yet there I was last Saturday, in that very position. Little did I know that that trip would become one of the most memorable ones of my first week in Paris.
It all started when I met Bruce, a zebra in the zoo who I decided to name myself. There I was–staring at two especially unexciting rhinos and wondering to myself whether there were any animals in this zoo that did anything other than sleep through the day–when, as if on cue, Bruce appeared out the brush and proceeded to feast on a nearby tuft of grass. He was almost close enough to touch, the intricate patterning of his dust-covered black and white stripes catching my eye. Never in my young adult life would I think that I would be so excited to see a zebra, but there I was, gasping and aweing with the eight-year olds beside me.
Bruce wasn’t the only new friend I made that Saturday afternoon. I had yet to see my favorite exhibit—the baboons. As I approached, the first thing I noticed was the large number of people watching from the viewing platforms. This must be a good one, I thought to myself. As I peered through the enclosure, I was surprised by their cacophonous action. There was always some baboon doing something hilarious somewhere in the cage—one chewing on some type of plastic, another swinging from tree to tree, yet another sitting up straight—quite peculiarly with its hands folded in its lap and looking like an old-time English professor.
However, I quite literally believe I got stars in my eyes when I caught sight of a newborn baboon with its mother. The baby—I named him Johnny—climbed on its mother’s back for a piggyback ride to the watering hole. When they arrived, Mom sat down, whipped Johnny around to her front side (her back to the viewing platform) and began breastfeeding. Soon enough, two other mothers arrived and started breastfeeding their babies, until there was a ring of nurturing mothers and their children. I was struck by the similarities in these baboons to human mothers—the way they cradled their children, the way they stroked their newborn’s fur as the baby suckled, the protective sidling of the mother whenever a male encroached into her area—with every minute I watched, I could see why these were our closest animal relatives.
Being the budding neuroscientist that I am, I started to consider the brain mechanisms for this behavior. In almost every animal species, mothers innately care for their young—this obviously makes sense in an evolutionary perspective, but what are the brain mechanisms for this behavior? What motivates it? What is the neuroscience behind it all?
An article by Kikuchi et al. (2015) addresses the neuroscience of maternal love. The experiment was designed to look at the brain activity of young mothers when viewing video clips of their 16 month old infants showing attachment behaviors. Mothers in an fMRI were shown either a clip of their infant smiling at them while they played together (play situation—PS) or of their infant being in distress when the mother left the room (separation situation—SS). The researchers hypothesized that the parts of the brain mediating maternal behavior would be more activated when the infant was in distress (SS) than when the infant was not (PS). After the fMRI, mothers were asked to rate their subjective feelings (happy, motherly, joyful, warm, love, calm, excited, anxious, irritated, worry, and pity) in response to video clips in PS/SS of their own infants and of other infants.
So, what did the researchers find? There were four brain regions found to be specifically involved in feelings of motherly love: the right orbitofrontal cortex (OFC), the anterior insula, the periaqueductal gray (PAG), and the striatum. After identifying these brain regions, researchers then had to interpret what these results actually meant. Essentially, the OFC and the striatum are involved in the dopamine reward system, which would involve the mother’s motivation to care for her infant. The OFC, insula, and PAG are involved in an information processing system mediating homeostatic emotions for the mother and the realization of motherhood itself. Since the OFC is involved in both systems, it is thought to play an important role in mediating between the two.
After all was said and done, researchers found that mothers did, indeed experience higher brain activation in SS than in PS. As subjective ratings of worry increased in the SS, activity in the right OFC increased. Good to know that mom cares.
What’s great about this article is that it provides a simple and straightforward model of measuring brain activation of mothers in response to their babies. It asks the mothers’ subjective feelings in addition to the neurological aspects. However, it can also be said that this method might be too straightforward—mothers are undoubtedly faced with more than two situations of maternal love and attachment. Perhaps in the future, the authors could consider approaching a more complicated model—one with more situations like a feeding or a stress situation. Also, it is definitely a challenge to quantify love in a scientific aspect as these article attempts to do—perhaps it might be too poetic for such a field.
Poetic or not, there is an undeniable beauty in the way a mother cares for her child—whether that mother is human, baboon, or zebra. Either way you look at it, Johnny the baboon is certainly well accounted for.
Yoshiaki Kikuchi et al. (2015) The Neuroscience of Maternal Love. Neurosci Common 2015; 1: e991. doi: 10.14800/nc.991.
Photos taken by yours truly.