Friend or Foe? Single Neurons in the Brain Control Social Interaction, Study Finds
Neurons live in a society, and scientists just found the ones that may allow us to thrive in our own society.
Like humans, individual neurons are strikingly unique. Also like humans, they’re constantly in touch with each other. They hook up into neural circuit “friend groups,” break apart when things change, and rewire into new cliques. This flexibility lets their collective society (the brain) and their owners (us) learn about and adapt to an ever-changing world.
To rebuild neural circuits, neurons constantly monitor the status of their neighbors through sinewy branches that sprout from a rotund body. These aren’t just passive phone lines. Dotted along each branch are little dual-function units called synapses, which allow neurons to both chat with a neuron partner and record previous conversations. Each synapse retains a “log” of past communications in its physical and molecular structure. By “consulting” this log, a neuron can passively determine whether or not to form a network with that particular neuron partner—or even set of partners—or to avoid any interactions in the near future.
Apparently, neurons can do the same for us. This week, by listening to the electrical chatter of single neurons in rhesus macaque monkeys, scientists at Harvard, led by Dr. Ziv Williams, honed in on a peculiar subset of neurons that helps us tell friends from foes.
The neurons, sprinkled across the frontal parts of the brain, are strikingly powerful. As their monkey hosts hung out for game night, the little computers tracked how each player behaved—were they more cooperative, or selfish? Over time, these “social agent identity cells” stealthily map out the entire group dynamic. Using this info, the monkeys can then decide whether to team up with other monkeys or shun them.
It’s not just correlation. By modeling the electrical activity of these neurons, scientists were able to accurately determine any monkey’s past decisions—and mind-blowingly, predict its future ones, basically “mind-reading” the animal’s next move. When the team tampered with the neurons’ activity with a short burst of electrical zaps, the monkeys lost their social judgment. Like the new kid in school, they could no longer decide who to befriend.
“In the frontal cortex, these neurons appear to be tuned for possible action from peers, representing them as communication partners, competitors, and collaborators,” wrote Dr. Julia Sliwa at Sorbonne Université in Paris, who was not involved in the study.
While the results are from monkeys, they’re some of the first to connect the activity of individual neurons to an extremely complicated yet necessary aspect of our lives. These data “are major steps in identifying the neural mechanisms for maneuvering in complex social structure,” she said.
My Brain’s View of You
We often think of neurons and circuits as hardware components that represent us: our perception, memory, decisions, feelings. Yet large parts of the brain are dedicated to representing other people in our external world.
One famous example is the “Jennifer Aniston neuron.” Back in 2005, an experiment showed that a single neuron in a person’s brain could react to a particular face—for example, Aniston’s. A lightbulb moment for neuroscience and computer vision, the study raised a brazen idea: that a single neuron has the computing power to encode a person’s physical identity.
In the real world, it gets more complicated than just identifying a face. A person’s face comes with history—is it my first time meeting them? What’s their reputation? How do I feel about this person?
Much work on how our brains handle social interaction comes from studying bands in music studios or teacher-student dynamics in classrooms. Here, brain activity is captured with wearables, which measure brain waves that wash over parts of the brain. These studies show that when making music or watching a movie together, our brain waves sync up. To rephrase, our brains tune into other peoples’—but when,...
Like humans, individual neurons are strikingly unique. Also like humans, they’re constantly in touch with each other. They hook up into neural circuit “friend groups,” break apart when things change, and rewire into new cliques. This flexibility lets their collective society (the brain) and their owners (us) learn about and adapt to an ever-changing world.
To rebuild neural circuits, neurons constantly monitor the status of their neighbors through sinewy branches that sprout from a rotund body. These aren’t just passive phone lines. Dotted along each branch are little dual-function units called synapses, which allow neurons to both chat with a neuron partner and record previous conversations. Each synapse retains a “log” of past communications in its physical and molecular structure. By “consulting” this log, a neuron can passively determine whether or not to form a network with that particular neuron partner—or even set of partners—or to avoid any interactions in the near future.
Apparently, neurons can do the same for us. This week, by listening to the electrical chatter of single neurons in rhesus macaque monkeys, scientists at Harvard, led by Dr. Ziv Williams, honed in on a peculiar subset of neurons that helps us tell friends from foes.
The neurons, sprinkled across the frontal parts of the brain, are strikingly powerful. As their monkey hosts hung out for game night, the little computers tracked how each player behaved—were they more cooperative, or selfish? Over time, these “social agent identity cells” stealthily map out the entire group dynamic. Using this info, the monkeys can then decide whether to team up with other monkeys or shun them.
It’s not just correlation. By modeling the electrical activity of these neurons, scientists were able to accurately determine any monkey’s past decisions—and mind-blowingly, predict its future ones, basically “mind-reading” the animal’s next move. When the team tampered with the neurons’ activity with a short burst of electrical zaps, the monkeys lost their social judgment. Like the new kid in school, they could no longer decide who to befriend.
“In the frontal cortex, these neurons appear to be tuned for possible action from peers, representing them as communication partners, competitors, and collaborators,” wrote Dr. Julia Sliwa at Sorbonne Université in Paris, who was not involved in the study.
While the results are from monkeys, they’re some of the first to connect the activity of individual neurons to an extremely complicated yet necessary aspect of our lives. These data “are major steps in identifying the neural mechanisms for maneuvering in complex social structure,” she said.
My Brain’s View of You
We often think of neurons and circuits as hardware components that represent us: our perception, memory, decisions, feelings. Yet large parts of the brain are dedicated to representing other people in our external world.
One famous example is the “Jennifer Aniston neuron.” Back in 2005, an experiment showed that a single neuron in a person’s brain could react to a particular face—for example, Aniston’s. A lightbulb moment for neuroscience and computer vision, the study raised a brazen idea: that a single neuron has the computing power to encode a person’s physical identity.
In the real world, it gets more complicated than just identifying a face. A person’s face comes with history—is it my first time meeting them? What’s their reputation? How do I feel about this person?
Much work on how our brains handle social interaction comes from studying bands in music studios or teacher-student dynamics in classrooms. Here, brain activity is captured with wearables, which measure brain waves that wash over parts of the brain. These studies show that when making music or watching a movie together, our brain waves sync up. To rephrase, our brains tune into other peoples’—but when,...
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