Neuroscientists in the US have found that this internal timer is weaker and stronger than most of us think. They also think that it could change how a whole country deals with aging, neurological disease, and even mental health in the next few decades.
Two parts of the brain that work like an hourglass
Scientists at the Max Planck Florida Institute for Neuroscience have figured out how two important parts of the brain work together to keep our movements in sync. Their research, which was published in the journal Nature, shows that the motor cortex and the striatum work together like a tiny biological hourglass, keeping track of time so we can do things at the right time.
Your brain has to be very accurate when you talk, hit a tennis ball, or even just reach for a cup. We don’t have a “time organ” like we have eyes or ears. Instead, timing comes from how neurons in networks send electrical signals to each other. Researchers knew that both the motor cortex and the striatum were involved, but they didn’t know exactly how they worked together.
Scientists now say that we can stop or reset our internal clock, just like you can stop or flip an hourglass.
The new study helps us understand how these two areas work together to keep track of time and start movement. It also gives hints about how to fix this process in people with Parkinson’s and Huntington’s disease, when timing and movement go wrong.
Teaching mice to “feel” one secon
To test the brain’s timing system, the team taught mice to do a simple but exact task: lick a dispenser at a certain time, usually one second after a cue, to get a reward. That one second turned out to be a powerful way to see the brain’s hidden timer.
Researchers watched thousands of neurons in the motor cortex and striatum while the mice waited and then licked. This let them see how neural signals changed over time, like grains of sand moving from one room to another.
- During the waiting period, the motor cortex sent out a steady stream of signals.
- The striatum slowly got more active in response to those signals.
- The mouse started licking when the activity in the striatum reached a certain level.
This pattern fit the hourglass metaphor that the scientists had suggested before the study very well.
How the hourglass in the brain really works
The top part of the hourglass is the motor cortex.
The motor cortex is in the front of the brain and is very important for planning and starting voluntary movement. In the new study, it worked like the top part of an hourglass, sending a steady stream of timing-related signals to the striatum.
These signals don’t show time like a number on a clock. They look more like patterns of neural firing that change slowly over hundreds of milliseconds. The brain can then use these patterns as a flexible guide, much like how a musician can feel the beat without counting every note.
The striatum is the bottom chamber and the place where decisions are made.
The striatum, which is part of a group of deep brain structures called the basal ganglia, acted like the bottom part of an hourglass. It slowly gathered the signals coming in from the motor cortex.
As this buildup got bigger, it brought the system closer to taking action. The movement was let go once the build-up reached a certain point. The lick happened at almost the same time as the peak of activity in the striatum, which shows that this part of the brain was the decision gate.
The motor cortex seems to send time, and the striatum turns that time into a choice to move.
Stopping and rewinding the brain’s clock
The most interesting results happened when the scientists used optogenetics, which uses light to turn off certain neurons for a short time, to turn off one area or the other.
Stopping the motor cortex: hitting the pause button
When the motor cortex was turned off for a short time, the timing signals stopped. The mice licked later than usual, which was a clear change in behavior.
At the neural level, the striatum’s activity stayed the same as long as the cortex was off. When it came back online, the timing pattern picked up right where it had left off.
Like pinching the neck of an hourglass to stop the sand from flowing, cutting off the motor cortex stopped the internal timer.
The brain didn’t “forget” how much time had already passed; it just stopped adding to it. The mouse’s movement was delayed because of that pause.
Turning off the striatum: flipping the timer
Turning off the striatum had a very different effect. The system didn’t stop; it acted as if the timer had been reset. When the striatum was quiet for a short time, the mice waited even longer to lick, as if time had gone back.
Neuronal recordings showed that the striatal build-up of activity started up again after the break, just like turning an hourglass upside down. The motor cortex kept sending out its flowing signal, but because the striatum’s accumulation process wasn’t working, that signal didn’t cause movement at the usual time.
Why this is important for a population that is getting older and sick
Movement disorders have a big effect on both the striatum and the motor cortex. For example, in Parkinson’s disease, cells in related basal ganglia circuits break down, which makes movement slow, stiff, and hard to start or stop. Timing goes wrong, and things you do every day become hard to predict.
Huntington’s disease also affects the striatum, which makes movements jerky and makes it hard to coordinate. The new results give us a clear picture of how these kinds of diseases could mess up not only strength and balance, but also the timing signals that help actions go smoothly.
| Brain area | Role in timing | What happens if disrupted |
|---|---|---|
| Motor cortex | Generates the flow of time-related signals | Internal clock pauses, movements are delayed |
| Striatum | Accumulates signals and triggers movement | Timer resets, movements become even more delayed or mistimed |
As populations get older, the number of people with these disorders goes up in whole countries. That puts a lot of stress on families, social services, and health care systems. Researchers can better plan future treatments by learning about timing circuits.
The results suggest therapies that not only enhance muscle strength but also seek to restore the brain’s internal perception of temporal awareness.
Future treatments: from lab mice to people
The new hourglass model could help doctors figure out how to change brain activity with drugs, deep brain stimulation, or, in the future, light-based methods borrowed from optogenetics. Instead of generally raising or lowering activity, doctors might try to bring back the right flow and accumulation pattern between the motor cortex and the striatum.
For instance, deep brain stimulation used to treat Parkinson’s could be adjusted to help the striatum do its job as a timing gate instead of just blocking bad signals. Rehabilitation programs could also be changed to teach timing directly by using rhythmic cues, gamified tasks, or virtual reality environments that reward precise, flexible movement.
Timing beyond movement: what else could be changed
Timing in the brain doesn’t just control how we move. It also affects how we talk, pay attention, make decisions, and even how we feel and hear music. A lot of mental illnesses, like ADHD and schizophrenia, show small timing problems in lab tests.
If the cortex-striatum hourglass is a common timing pattern, its breakdown could have a big effect on mental health, education, and productivity. Countries are already seeing more cases of attention and movement disorders in kids being diagnosed. Better timing models might help schools improve their screening tools and interventions.
Important words to explain
Striatum: A deep part of the brain that gets information from many areas of the cortex. It helps you figure out what to do and when to do it. It plays a big role in forming habits and behavior that is based on rewards.
Optogenetics is a lab method that changes the genes of neurons so that they respond to light. Then, by shining light through tiny optical fibers, scientists can turn those neurons on or off at just the right time.
Internal clock: Not just one organ, but a network process that lets the brain keep track of time in milliseconds to seconds. Each network can handle a different range of time, and they can be trained like a muscle.
What this might mean for everyday life
Think about driving in a lot of traffic. You have to time your braking and speeding up to the hundredth of a second. A small change in the brain’s hourglass could mean the difference between a smooth stop and a small crash. Timing is very important for safety and performance on factory floors, in operating rooms, on sports fields, and in busy cities.
Classes that focus on timing, like rhythmic movement classes, music practice, or sports drills, may help these brain networks stay healthy. No exercise can reverse severe degeneration on its own, but keeping the cortex and striatum busy with different tasks that need to be done quickly might help them stay functional longer, especially in older people.
The new study doesn’t give us a quick fix. It does, however, help us see a hidden mechanism that affects the health of the whole country: how well our brains can still feel the passing of a second and move at the right time.
