Mapping the Brain’s Internal Stopwatch

Summary: Whether it’s Jannik Sinner timing a 100 mph serve or you judging how long to wait at a yellow light, the brain is constantly calculating the passage of time. A new study has mapped the brain’s internal “stopwatch” for the first time.

Using high-field fMRI, the team discovered that time perception isn’t a single “ping” in one area; it is a relay race across the cerebral cortex, transforming raw visual data into a subjective experience of “long” or “short.”

Key Facts

• The Three-Stage Relay: Time perception moves through three distinct phases:
  1. Occipital (Visual) Cortex: Encodes “physical” duration. The longer a stimulus lasts, the stronger the neural response (monotonic).
  2. Parietal & Premotor Areas: Translates that signal into “selective” representations. Specific groups of neurons fire only for specific durations (e.g., a “half-second” group vs. a “one-second” group).
  3. Frontal Cortex & Anterior Insula: Categorizes the time subjectively, allowing us to decide if something felt “too slow” or “just right.”
• Mechanistic Model: This study moves beyond just “where” time is processed and proposes a “how” model—showing the physical transformation of data from a simple signal to a complex decision.
• The Subjective Glitch: The research explains why time can feel “distorted” (e.g., during a car accident or a high-stakes tennis match); the final “categorical” stage in the frontal cortex can be influenced by emotion or focus.
• Precision Timing: The second stage (parietal/premotor) is the “readout” phase, which is likely what athletes like Sinner have highly optimized to achieve millisecond precision.

Source: SISSA

How does Jannik Sinner manage to hit the ball at exactly the right moment, with remarkable precision? And how do we, in everyday life, perceive the duration of events around us?

The answer lies in how the brain constructs the perception of time, as shown by research published in PLOS Biology by Valeria Centanino, Gianfranco Fortunato, and Domenica Bueti. Starting from what we see—such as an approaching ball—temporal information is processed by the brain through progressively more complex stages: from the occipital visual cortex, to parietal and premotor areas, and finally to frontal regions.

Using high-field functional magnetic resonance imaging (fMRI) and measuring time perception in healthy volunteers, the researchers shed light on what happens in the brain when we estimate the duration of a visual stimulus.

“Our results show that time perception is not a unitary process, but the outcome of multiple processing stages distributed across the cerebral cortex,” the authors explain. “Each stage contributes differently, from encoding physical duration to constructing the subjective experience of time.”

In an initial stage, occipital visual areas encode duration through gradual (monotonic) neural responses: the longer the stimulus, the stronger the neural response. This information is then transformed in parietal and premotor regions into selective (unimodal) representations, where distinct neural populations respond preferentially to specific durations, enabling the “readout” of time.

Finally, higher-order regions, including the frontal cortex and anterior insula, are involved in the subjective categorization of duration, shaping how time is perceived.

The PLOS Biology study goes beyond identifying where time is processed in the brain, proposing instead a mechanistic model of how temporal information is processed.

This new framework not only advances our understanding of time perception but also opens new avenues for investigating how the brain constructs subjective time—and why this experience can sometimes be distorted.

Key Questions Answered:

Editorial Notes:

• This article was edited by a Neuroscience News editor.
• Journal paper reviewed in full.
• Additional context added by our staff.

About this sleep and neuroscience research news

Author: Donato Ramani
Source: SISSA
Contact: Donato Ramani – SISSA
Image: The image is credited to Neuroscience News

Original Research: Open access.
“Neuronal populations across the cortex underlie discrete, categorical, and subjective representations of visual durations” by Valeria Centanino, Gianfranco Fortunato, and Domenica Bueti. PLOS Biology
DOI:10.1371/journal.pbio.3003704

Abstract

Neuronal populations across the cortex underlie discrete, categorical, and subjective representations of visual durations

The neural processing of subsecond durations recruits a wide network of areas. Although unimodal tuning has been shown in many of these regions, its role and link to perception remain unclear.

Here, we used 7T functional MRI while participants performed a visual duration categorization task to characterize unimodal responses along the cortical hierarchy.

We found topographically organized neuronal populations tuned to all presented durations in parietal and premotor cortices, and in the caudal supplementary motor area (SMA).

In contrast, rostral SMA, inferior frontal cortex, and anterior insula showed neuronal preferences centered around the mean duration, which correlated with the boundary duration participants employed in the task.

These differences suggest specialized roles of duration tuning across cortical regions —from discrete to categorical and subjective duration representations.

Finally, correlations of neuronal preferences across areas highlighted a hierarchical organization of duration tuning.

Together, our findings provide a mechanistic framework for duration perception in vision.