PULSE

• potentially infinite

• originates in the mind

• involves motor and memory areas of the brain

• can be synchronized with the outside and measured via EEG

• common denominator between two contrasting events

• well represented by impulses shorter than 100 ms

The pulse is first and foremost a mental phenomenon: it’s that sensation that makes us tap our foot when we listen to music and allows us to organize and relate different musical events, in a way, to measure them. The pulse is the unit of measurement of time. We often associate it with the sound of a metronome, but the pulse resides in our mind and is, potentially, infinite.

EXTERNAL SYNCHRONIZATION¹

What do the changing seasons and the heartbeat have in common?

Both are examples of how our mind interprets the contrast between opposing events as a pulse. In the case of the heart, the alternation between contraction and relaxation creates a pattern we perceive as rhythm. With the seasons, the alternation between warm and cold periods forms a cycle that we interpret as a regular rhythmic flow.

Would you like to merge autumn and winter into one season or group heartbeats into fives? You can! Your mind is in control².

Of course, the contrast between events is something that nearly all humans can perceive through their senses, and that’s why it can coordinate us as a species and ensure that in both Japan and Argentina the seasonal sequence is the same. Pulse is also a tool of social connection.

ARTIFICIAL PULSE

Let’s consider the division of hours or years: this doesn’t happen the same way everywhere, and minutes are not always tied to natural phenomena. We could decide to divide hours into 100 parts, and if everyone adopted that division, it would become the new standard. Humans have the extraordinary ability to detach from nature and invent their own artificial periodicity, which others can then connect to.

If I arbitrarily choose a 4/4 pulse at 80 BPM, other musicians can sync their internal pulse to my tempo. When we play an instrument or sing, we rely mainly on an artificial pulse created by the human mind—even in the absence of natural phenomena.

This shows how the mind can maintain an internal periodicity that guides our perception and musical production, syncing its clock with both objective, natural phenomena and artificial ones created by humans.

SCIENTIFIC DISCOVERIES

From the first months of life, humans can "lock onto" internal and external pulses and maintain a rhythm³. This phenomenon has been demonstrated through EEG studies. The results show that, when listening to music, EEGs record spikes of electrical activity in motor and memory areas of the brain.

Another interesting finding is that while the brain’s response to simple (isochronous) rhythms allows little variation, responses to more complex or syncopated rhythms are less coherent.

SUBJECTIVITY⁴

In fact, in complex musical pieces, different people may perceive different pulses. This is because our brains struggle to anticipate pulses in rhythms that aren’t simple, and tend to organize sounds into patterns that make sense to us, based on personal experience and musical culture. The mind is not just a passive receiver but an active creator in the interpretation of pulse⁵.

A masterful example of how different interpretations of pulse can synchronize and collaborate is In C by Terry Riley. An even clearer example of how pulse can detach from any common denominator and follow each performer’s subjectivity—even within an ensemble—is Garden of Delights, by Mauro de Maria⁶.

ANTICIPATION

Have you ever noticed how your brain anticipates the beat of your favorite song? This happens thanks to neural dynamics of excitation and inhibition, which lead us to imagine the presence of one or more internal oscillators, like metronomes in our head. These oscillations allow the brain to predict when the next event will occur, helping us process time in music and improve our ability to anticipate the next pulse.

When an external pulse suddenly stops, the EEG still shows signals, proving that our brain can anticipate events even when they’re no longer audible. If the pulse continues but is disrupted by a change in timbre or pitch, a break or contrast occurs. In that moment, the EEG keeps showing the pulse but simultaneously recalibrates to create a new series or sequence.

RESET

When there’s an error in the external pulse, the human mind “resets” thanks to neural adaptation and plasticity mechanisms. EEG studies show that the brain detects inconsistency and generates a rapid activity spike to correct the rhythmic model. This process involves the prefrontal cortex and motor areas responsible for anticipation and synchronization. The mind doesn’t just adapt—it generates a new prediction based on the changes, ensuring a continuous perception of rhythm even in disrupted situations. This phenomenon shows the incredible flexibility of our nervous system.

PULSE IN NEUROLOGICAL DISORDER TREATMENT

Pulse and rhythm have significant implications in therapeutic contexts, especially for neurological disorders. In Parkinson’s patients, rhythm-based therapies have shown promising results in improving motor coordination. Synchronizing with external rhythmic stimuli can help compensate for movement control issues.

Dyslexia involves difficulties in decoding written and spoken language. Studies show that people with dyslexia have a reduced ability to track low-frequency temporal information in speech. Rhythmic exercises can improve neural synchronization and enhance reading and comprehension skills⁷.

CONCLUSION

Pulse connects natural and artificial rhythms, involving brain areas such as auditory, motor, and memory regions. EEG studies show that from the first months of life, we can synchronize with external pulses and even anticipate them. One of the most important characteristics of our internal clock is its ability to connect with external ones, whether natural or artificial: being a musician often means exactly that.

Notes

1. This synchronization process is called entrainment, and it is modeled as one or more internal oscillators [Schroeder et al., 2008]

2. See, for example, Latin American music, where the clave is often more implied than played. Similarly, timelines in African music serve as time structures even when inaudible, as with certain melodies in Balinese culture.

3. At minute 1:34, Rhythm and the Brain: Surprises from Cognitive Neuroscience 

4. For instance, when listening to a song with rich rhythmic layers, one might anchor the beat to the bass line, to the drums, or to another instrument, generating different interpretations of the same rhythm.

5. Rhythm and Shifting Our Perception | David Alderdice | TEDxPaonia

6. Mauro de Maria, Jardín de las delicias

7. At minute 13:37, Rhythm and the Brain: Surprises from Cognitive Neuroscience