Thread by @realscientists

Gooooood Sunday, science fans! My name is Sarah and I'm your scientist this week tweeting from Tkaronto/Toronto/Toronno, unofficial raccoon capital of the world!

I'm a PhD student at the University of Toronto, and I study brain activity related to music listening/music-making, and how this activity changes as we age.

Let's get started with some hard-htting science. Please select the most epic Céline Dion power ballad. I'll explain later.

Onto the brain. The brain, according to 100% of scientists living in my apartment and, I suspect, a fair number of people I work with, is a squalling bag of cats.

There's stuff we're pretty sure we know, stuff we kind of know, and The Rest. The Rest is massive. This is awesome.

Back in the day, the brain was thought to be neatly organized with specific areas corresponding to specific behaviours or states (Way Back, the brain was probably thought to be some kind of head-bladder that oozed mightily when one was struck by magic, or something)

Doctors were able to identify certain specific areas governing certain behaviours using people who had suffered head injuries (these are called lesion studies and still happen today).

Studying the brain's structure was slightly more invasive, as it required removing the brain from the skull.

When Hans Berger discovered a way to record brain electricity (in other news, the brain is electric. I'll explain later) from people who were still alive, possibilities to study more complex activities in healthy and lesion individuals opened up!

This method is called EEG (electroencephalography), and it records very subtle electrical activity generated by groups of neurons firing together.

EEG is able to pick this up using electrodes placed on the scalp. These electrodes act like microphones and send the signal to an amplifier which then boosts the signal enough to be recorded on a computer. In Berger's time, they would have used needles and ink. Neat!

SO. By imaging the living brain, we can hook up our lovely participants to an EEG, have them recite poetry and locate the poetry centre of the brain, right?

Turns out the brain does a lot of stuff all the time, and pinpointing exactly where, how, and what it does to act or react is not the same for every person. The brain is crafty. Not unlike a bag of cats.

As with other sciences, studying lots of people's brains gradually starts to sketch-out certain standard patterns of behaviour. These can be very localized responses to very precise stimuli, or more general, whole-brain states.

THIS allowed for the identification of large structures (called lobes), and scientists have been chipping away at what the lobes do ever since.
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Let's take the visual cortex (played by Idris Elba)! If you have a complete brain and both eyes, you have a primary visual cortex toward the back of your head (in the occipital lobe neighbourhood) connected to the eyes via the optic nerve (don't try to touch it)

The visual cortex responds to visual stimuli, but subdivisions also respond to specific information, such as faces, written words, numbers, and written music. The visual cortex also responds to braille in braille-readers.

While these seem to support the "everything in a neat little box" theory by the dead-scientists-and-mutton-chop-enthusiasts-of-the-Victorian-era club, these are individuals pieces within a larger machine.

Let me explain it with cake. Individual brain areas are like ingredients, and the behaviour/action/reaction they produce is the recipe. Just like a cake is a combination of ingredients, a cognitive task (one that involves thinking) is a combination of brain areas.

We'll nerd out about this later in the week, but for the moment, think of these brain area cakes as networks. Networks can share components, and may rely on one specific area to take the behaviour from A to B, but teamwork is essential.

And now music! I want to hear from you before we jump into music. Is there a particular song that describes you or your work? Or perhaps even your brain?
(🎨 The Awkward Yeti)