E. burchellii hunt in massive swarms, hundreds of thousands of ants strong. When faced with slippery slopes, they team up to form living structures called “scaffolds,” making footholds for the ants coming up behind them.

To model how ant colonies shape their behavior to the environment, researchers traveled to Barro Colorado Island, Panama. They built a moveable platform that could be tilted from 20 degrees (mostly flat) to 90 degrees (completely vertical), set the platform along the ants’ path, and watched. The steeper the slope, the denser the scaffold. Why? Selfish behavior. 

If an ant slips as they're climbing a precarious surface, they will dig in, gripping the underlying surface. Their body acts as a foothold, making the climb less slippery for the rest of the swarm. As more ants slip and catch themselves, their bodies add to the scaffold. As the surface becomes easier to grip, fewer ants slip, and scaffold construction winds down to a halt. This is an example of proportional control, where a system responds in proportion to the amount of error it detects. The rate at which bodies are scaffolded (the system’s response) decreases as fewer ants slip (the error it detects). 

Ants and their remarkable collective behaviors can inspire us to improve our own infrastructure. Mechanisms inspired by E. burchellii scaffold-building, which robustly and quickly respond to change, could be used to design self-healing fabrics, build better traffic control systems, and more.

A September 2020 study published in Nature employed an impressive lineup of cutting-edge tools to address this impossible question: how can our brains disconnect us from ourselves?

Neuroscientists identified slow brain waves in the retrosplenial cortex, a key player in learning, imagination, and autobiographical memory, as a hallmark of dissociative states. They injected mice with sub-anesthetic doses of ketamine to induce dissociation, then peered into their brains through their transparent skulls. After ketamine injection, an unusual, slow brain wave emerged in the retrosplenial cortex, oscillating at about 2 Hz (the same beat as Carly Rae Jepsen’s Call Me Maybe).

Using light to stimulate genetically-modified neurons in the retrosplenial cortices of the mice, they recreated the same beat, sending the mice into a dissociative-like state without any drugs at all. A specific ion channel, HCN1, seems to be responsible for setting the tempo of these dissociation-linked brain waves. 

And it’s not just mice. A human epilepsy patient, who regularly experienced pre-seizure dissociative auras, demonstrated the same brain waves in the same region identified in mice. When researchers elicited the beat via electrical stimulation, the patient reported dissociative episodes: “...the same way a pilot can lose control of a plane, I got pulled out of the pilot’s chair, but I could still see all the gauges.” 

When a group of neurons oscillates on the same wavelength as another group, it’s easier for them to communicate. Dissociative slow brain waves seemed to decouple the brain regions implicated in forming our sense of self from those required for perceiving, planning, and action. 

Moving forward, the technology used here may equip scientists to dive deeper into the study of consciousness, helping us understand how the brain creates the mind. 

And yet, relationships find a way. We still feel obligated to check in on our parents, join virtual work happy hours, and bring groceries to elderly neighbors. Does this sense of obligation bring us closer together, or fuel resentment that drives us apart? 

The short answer: it’s complicated. 

Psychology researchers at Michigan State University found that not all obligations are created equal. They analyzed the results of an 18-year-long study of middle-aged adults and their relationships, and observed that while some obligation strengthens bonds, too much obligation breaks them. 

Light obligation, like sharing a virtual glass of wine with an old college friend, was correlated with improvements in well-being across the board. But when favors become disruptive or financially burdensome, the trend flips: substantive obligation was linked to more depressive symptoms and increased strain on friendships over time. 

This study was one of the first to investigate how obligation impacts relationships in middle-aged adults, a largely underlooked demographic in the field. Amidst this pandemic, many middle-aged adults find themselves caught in an impossible relationship juggling act. Working from home while taking care of children, connecting with romantic partners while checking in on elderly parents — obligation may be the glue holding us together, whether we like it or not.

The spleen is controlled by the autonomic nervous system, which also triggers the fight-or-flight response. But it’s also getting commands from higher up: the brain itself.

In a recent study, scientists identified the “brain-spleen axis,” a pathway linking the midbrain to the spleen that enables the brain to directly regulate immune function.

Researchers removed nerves from the spleens of mice, then injected the mice with antigens that should produce the immune cells that trigger antibody release. Without brain-spleen communication, immune cell production shut down. Two brain regions sent the bulk of these signals: the central nucleus of the amygdala, and the paraventricular nucleus of the thalamus. 

Both regions activate when we’re stressed and regulate production of stress-related hormones. When mice were placed in stressful situations (like standing on a high, transparent platform), stress hormones released from the brain slowed down antibody production in the spleen.

If this brain-spleen axis also exists in humans, it raises an exciting possibility: by strategically activating certain brain regions through behavioral intervention or noninvasive stimulation, we may be able to boost immune function. 

Ancient Greek physicians weren’t quite right, but they were on to something: the brain and the body (yes, even the spleen) are in constant communication, and we’re just beginning to understand their language.