Emotional Memory and Romantic Pair Bonds

“Love is so short, forgetting is so long,” Pablo Neruda.

The animals mate. Their partner’s odor whizzes through their nose into the brain’s olfactory nucleus, where neurons filled with the attachment hormone oxytocin rush into the hippocampus to form an emotional memory. Inside the hippocampus, the brain structure that presides over memory and learning, engrams develop to create the social memory. As the neurons representative of memory traces and the physical changes involving remembrance, engrams then interact with the pleasurable hormone dopamine to convert the retrieval of the memory into a rewarding experience. 

The interplay between oxytocin, the hippocampus, engrams and dopamine in memory creation and retrieval convert reminiscing into an act of social cognition. Social cognition refers to the way humans process and react to external sensations and social stimuli. It involves attention, perception, action, planning and memory. In the neurobiology of affection and remembrance, social cognition informs how we recall and bond with our loved ones. 

Memories of Pair Bonding 

“Social cognition is facilitated by oxytocin receptors in the hippocampus, a brain region that changes dynamically with pregnancy, parturition, and parenting experience,” said a group of researchers from the University of California in a recent 2020 study about affiliation in titi monkeys. Another 2019 study by the scientists of Kanazawa University in Japan, researched how the movement of oxytocin in the brain facilitates maternal bonding in mice. The investigations draw similar conclusions –that oxytocin rushes in the hippocampus precede emotional memories, unleash feelings of rewards, and induce pair bonds. 

Most explorations of pair bonding have involved monogamous rodents known as prairie voles. One such 2018 experiment involving Atlanta’s Emory University researchers Hasse Wallum and Larry J. Young describes pair bonding as the “evolutionary antecedent of romantic love.” According to doctors Wallum and Young, pair bonding refers to a monogamous intimate relationship between two adults of the same species, that mate and share both parental duties and territory. In humans, love and romantic attachments result from mating and pair bonding. 

As a subset of social cognition that facilitates pair bonding, memories of our loved ones occur from a heady potion of oxytocin and dopamine in the hippocampus. While oxytocin modulates parental nurturing, facial recognition, empathetic behaviour and social bonding, dopamine regulates reward perception, reinforcement learning and addiction. 

The neural pathways that translate sensory input into romance, whilst allowing us to reflect on past interactions with our partners and on a future together, catalyze in pair bonding. That is, social cognition catalyzes romantic love. 

Love in the Hippocampus 

Memory enables relationships. As one of the brain regions regulating mood and memory, lesions in the back of the hippocampus impair cognition and memory, while lesions in the front of the hippocampus alter emotional behaviour, social interactions, and stress resilience. We cannot form an attachment without remembering the other person. Without reflecting on our relationships, we cannot develop empathy. 

According to Rubin and colleagues, “the ability to form and maintain social relationships may also involve contributions from hippocampal representations that support the ability to imagine and reflect upon experiences with other people.” The researchers measured empathy through a series of questionaries related to perspective-taking, emotion contagion, emotional responsiveness, and empathetic concern. Patients with hippocampal amnesia exhibited less empathetic responses and difficulty when incorporating emotional memories into prosocial behaviours. 

When processing emotional memories, the hippocampus interacts with the amygdala –the brain region that inputs and interprets emotion. While the hippocampus stores memories and enables synapses between neurons, the amygdala gives meaning to emotional cues, allowing for the formation of social engrams. When recovering the memory of our loved ones, the engrams cause the synapses to exchange dopamine and oxytocin, turning the retrieval of the memory into a rewarding experience, offering empathetic responses, and strengthening social bonds. 

Source: The Scientist (Catherine Offord, 2020). 

The hippocampus interacts with the amygdala to encode and decode emotional memories. 

Emotional Memories 

Emotion heightens memory. Sharon, Delgado and Phelps say that we remember affecting events in vivid detail, like a camera’s flashbulb. Due to their personal significance, flashbulb memories involve the recollection of places, activities, and people during an enduring and affecting experience such as falling in love. In people suffering from memory loss, synapses break yet the emotion remains. Even when they cannot remember the intricacies of the event, the experience leaves “a scar upon the cerebral tissues.” There is truth to the old adage, “people will not remember what you said, but they will remember how you made them feel.” 

Engrams encode emotional stimuli into long term memory. Emotional synapses leave a durable memory scar. Love is hard to forget. 

Sources

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