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Rhythm

It's funny about how our brains work. We all like patterns; we feel satisfaction when things are organized in a certain way. My work focuses primarily on that: finding visual patterns and turning them into a story, with the most essential description possible, of course.

I've never met anyone who says they hate music; maybe they like weird music, (there’s always someone, right?) but we all undoubtedly enjoy mosaic-like fragments and certain sounds, those fragments get stuck in your head, certain jingles can live in a corner of your brain for years, whether you like them or not.

I started this short article after I came across with this paper from the Center for Biomedical Research in Music at Colorado State University. That study suggests we use different areas of our brain to interpret sound patterns, meter and tempo.

In other words, our brain is wired to make us not just listen the sound but somehow “feel it” in different ways, understand timing, anticipate patterns and it flow intuitively. That might explain why you might remember a sticky rhythm pattern and hate it at the same time. The are of the brain in charge of patterns probably is having such a good time that its swimming in dopamine.

brain activity while listening to rhythm patterns, tempo and meter

Here’s a little fun experiment, first turn on you audio, then enable instruments by tapping each box and create a sound pattern, then hit the play button underneath and adjust the sound until you find something pleasant.

The experiment above is inspired in the great 2009 beatboxing experience created by So Far So Good (SFSG) Incredibox and Google’s Chrome Music Lab, both classic experiences that I really enjoyed many years ago and still work as good as they used to be.

One of the most interesting things about Incredibox was the option to adjust the sounds; I think it stimulated just the right part of the brain to hook us into the stimuli.

Here’s another player, same logic as the one above, but now you can adjust the tempo anytime to add some different stimuli to the right side of your brain.

200
100 300

It’s really interesting how our brain works. Maybe it’s worth taking a little look into the nerdy world here.

Interpreting sounds

These are things that one doesn’t usually stop to think about, but how does our brain know that something is making a sound? Most of the people know that there are waves involved, maybe having two ears might help to find the origin of the sound, but the truth is that the process is simply wonderful. Think about it for a second. A vibration is created somewhwre, it travels by air or liquids as waves and it has to get converted into electric signals so brain can make sense out of it.

Let’s start where we get the first contact. The sound waves first touch our ears and get received through a narrow channel to the eardrum.

A diagram of the ear showig where the eardrum is

Middle ear

Outter ear

Temporal bone

Ear canal

Ear

Eardrum

The vibrations generated by the eardrum are collected and modified by the auditory ossicles in the inner ear which passes the sound as vibrations to the cochlea.

A diagram of the middle and inner ear

Middle ear

Inner ear

Ear canal

Eardrum

Ear

Cochlea

Auditory ossicles

Temporal bone

Up to this point, it’s mostly a mechanical process of movement, filtering, and calibration. But when you enter the cochlea, that snail-shaped organ, things get mysteriously interesting. Inside there, the fluid responds to these vibrations by creating waves.

A diagram of the inner structure of the cochlea showing how sound vibrations are converted into electrical impulses

Low pitch

High pitch

350Hz sound

4,000Hz sound

Different areas of the organ react to different sounds; high frequencies cause vibrations in the stiffer, narrower base of the basilar membrane, and lower frequencies cause vibrations in the more flexible, wider apex.

A diagram of the cochlea showing how different areas respond to different sound frequencies in Hz

The cochlea

5,000Hz

4,000Hz

3,000Hz

2,000Hz

1,500Hz

Cochlear duct

Basilar membrane

1,000Hz

800Hz

600Hz

400Hz

200Hz

Apex

Zooming in aven further, inside the cochlea, the movement of little filaments causes a chemical reaction that generates electrical impulses.
Those impulses are sent instantly to the brain to be interpreted as different sounds.

A diagram showing how sound vibrations are converted into electrical impulses by the hair cells

Hair cells

Stimulus

Impulses

Neurotransmitters

It is important to note here that the brain calibrates all of this in harmony with other senses; these signals are contrasted with what the eyes see. If the signals are confusing and do not match what your eyes see, you get dizzy.

Our systems are truly amazing, don't you think?

Sources:
PUBMED Human brain basis of musical rhythm perception: common and distinct neural substrates for meter, tempo, and pattern.
freesound.org – sound samples by:
mutatorscotch
musiclab – sound samples by:
Google Creative Lab.