From the gut to the brain, the body runs on the same rhythm

The body runs on rhythms. A new analysis shows that neighboring parts of the gut can tick at almost the same pace. When that happens, they synchronize and form shared plateaus that move and churn food in a smooth, organized sequence.

Each section follows the next in a precise rhythm. The same mathematical principles also help explain how tiny blood vessels in the brain maintain their steady beat.

Measuring gut rhythms

The team worked in San Diego and Paris, testing a classic physics model against real intestinal data. The core timescale is slow, on the order of several seconds per cycle, which is easy to measure.

The study was led by David Kleinfeld, a professor of physics and neurobiology at the University of California San Diego (UCSD).

Kleinfeld’s research is focused on how neural activity couples to blood flow and how physical rules shape living systems.

The gut advances meals with peristalsis, rhythmic squeezes that push food one way. Those squeezes ride on slow electrical waves that coordinate muscle, and they arise from specialized cells embedded in the wall.

Gut timing at the cellular level

At the cell level, the timing hardware comes from the interstitial cells of Cajal, the gut’s electrical pacemaker cells.

These cells generate slow waves that coordinate both movement and mixing within the gut – a pattern seen across many species.

Interstitial cells of Cajal (ICC) form intricate networks, transmit electrical signals to smooth muscle, and establish the local rhythm that keeps everything in sync.

Along the small intestine there is a frequency gradient, a slow change in natural tempo along the gut.

Upstream regions beat a bit faster, and downstream regions beat a bit slower. This invites the faster region to pull the slower one into line.

The gut’s rhythmic staircase

Kleinfeld and colleagues wanted to know what happens when many self-driven units sit along a ramp of frequencies.

The study showed that a slight difference in pace can lead neighbors to march together into shared plateaus, a hallmark of oscillator networks.

To capture this, the team used a Ginzburg-Landau model, a standard equation for patterns in physics. They added the biological twist of a one way frequency gradient and then solved for when and where clusters form, as detailed in their analysis. 

Inside those clusters are edges called a defect – a gap in the pattern where amplitude drops.

The math ties those edges to an effective change in diffusivity, how activity spreads to neighbors, so that spreading weakens in just the places where plateaus split.

Every part of the intestine works like an oscillator talking to the next one down the line. Because the gut moves in just one direction, its rhythmic staircase forms cleanly and in order.

Activity in the brain’s small vessels

Small arteries in the cortex do not just sit there. They show vasomotion, slow vessel diameter oscillations, near one-tenth of a hertz in many settings, and those oscillations help stabilize flow.

Neural activity can bring those vessel rhythms into alignment. In mice, activating specific neurons causes arterioles to fluctuate in diameter in sync with the neural firing, shifting their timing.

This demonstrates a direct connection between neuronal spikes and changes in vessel tone, supported by independent evidence.

The same coordination that drives the gut appears again in the brain’s small vessels. This matters for cleanup.

Slow vessel motion drives paravascular clearance – the flow of fluid along spaces around arteries and veins. When this motion weakens, waste removal can slow, as shown in aging and disease studies.

Math explains the gut rhythm

The new theory explains when plateaus appear, how many steps form, and where they break. It also shows that two distinct patterns can emerge – either a train of plateaus or one broad, phase-locked state.

A clear boundary separates these states, and crossing it is possible by adjusting the gradient or the coupling, according to the study.

Those boundaries are not just abstract lines. They map to real control knobs, like how strongly neighboring segments talk or how steep the gradient is across a few inches of bowel.

In the brain, the knobs might include vessel wall mechanics or how far neural spikes spread.

“The mathematics had been solved in an approximate way before now, but not in a way that gave you these breaks and what happens at the breaks. That is a critical discovery,” stated Kleinfeld.

Gut rhythms and health

When this timing system falters, the result is a motility disorder, a condition where gut movement is impaired. 

The model identifies parameters that might be tested in future experiments, including how gut rhythm and ICC networks couple and how the gradient shifts across disease states.

In the brain, similar tests could probe how anesthesia, sleep, or injury change vessel plateau structure.

Researchers can now ask whether a multi-path staircase emerges in cortex and whether it predicts how well tissues get oxygen and clear waste, guided by prior imaging.

The study is published in Physical Review Letters.

Image details: Optical image of the surface vasculature of a mouse brain showing the complex network of arterioles operating at various frequencies with periodicity ranging from 6.6 to 20 seconds.

Image Credit: David Kleinfeld / UC San Diego

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–