Some neuroscientists are confused

Updating our model for how the brain works... plus some links!

This summer, I wrote a series of stories about the Thousand Brains Theory of Intelligence which postulates that the neocortex is subdivided into hundreds of thousands of cortical columns which each build models of the world and work together to retrieve knowledge by voting. If you missed these essays, I highly encourage you to check them out.

The Thousand Brains theory is still unproven and, while backed by some empirical evidence, is largely supported by logical deduction and mathematical models—not observational data from brains.

However, I saw a story from The Atlantic a few weeks ago that I think actually connects to what we’ve been exploring here on Synapse and I wanted to share it with you.

The story is about how neuroscientists Carl Schoonover and Andrew Fink have confirmed a rather puzzling phenomenon in the mouse brain called representational drift. Essentially, the research team recorded how specific neurons in a mouse’s brain respond to a smell sensation over the course of several weeks. They were surprised to find that the neurons that responded to the smell actually changed overtime—the neurons that responded on day 1 would not be the same ones to respond a few weeks later.

This is surprising given that the textbook definition of how the brain works involves our neurons “encoding” information about the world in their various connections with other neurons as they respond to different stimuli. If the neurons that respond to the world are constantly changing, how does the brain keep anything straight?

Well, if we think about what the Thousand Brain theory says, this could actually make sense. First, it’s not surprising that multiple areas of the brain are capable of understanding the same stimuli given that the Thousand Brains theory postulates a universal algorithm of intelligence that is used by every column in the neocortex.

Second, the Thousand Brains theory says that the brain can recognize stimuli (like smells) by combining the votes of individual columns. Jeff Hawkins describes this voting by having you imaging you are reaching into a black box for a coffee mug. Each of your fingers are touching a certain part of the coffee cup with incomplete information. One finger might be touching the rim and thinks this could be a mug or a cup. One finger could be touching the side and think that this could be any round object. One finger could be touching the handle and think that the object is a jug. Each of these columns puts a vote into what it thinks the object is. Only together does the brain know by consensus that the object is a coffee mug.

Some neuroscientists are interpreting this representiatonl drift as evidence of a consensus mechanism like seen in the Thousand Brains Theory. Here’s Timothy O’Leary:

“Individuals in a population can change their mind while maintaining an overall consensus. The number of ways of representing the same signal in a large population is also large, so there’s room for the neural code to move”

Overall, it was nice to see connections to our deep dive on intelligence in the contemporary media and current observational research. The Thousand Brains theory is so broad and applicable that I suspect we are going to keep running into examples of how our observations of how the brain works could be explained by this theory.

🔗 Links

Dance Till We Die: Why COVID Security Theatre Failed

This is a really great piece by Ari Schulman about all of the theatre around our mitigation of COVID transmission. By theatre, Schulman means:

“So for the last year, we have worn masks in restaurants—unless we were sitting down. We have stayed six feet apart—whether we are running by on the sidewalk or sitting a table away inside for hours. We have stood behind plastic barriers at the DMV and the checkout counter—even though we know COVID floats in the air.”

I’m among those who have privately and publicly criticized the pointless measures organizations take to appear to be taking the pandemic seriously (especially surface cleaning!), but what I like about this piece is that it offers a balanced view at the good that theatre can do in public health along with a critique of how our theatre has gone wrong over the last 18 months. Well worth a read.

Where did coronavirus come from? What we already know is troubling

Many of you have likely already seen this NY Times Op-Ed piece written by the brilliant Zeynep Tufekci. But in case you haven’t, you really should take the time to read this deep analysis on the conflicting facts surrounding the emergence of this virus. It’s been a fascinating story so far and one of great importance if we wish to prevent this from happening again.

10+1 Things by Rishikesh Sreehari

10+1 Things is a fantastic newsletter that I thought some of you might be interested in. Here’s what Rishikesh has to say about what 10+1 Things is all about:

Content on the internet is growing exponentially. In fact, 90% of the data available on the internet today has been created. It has become difficult to cut through the noise and find the right content since every day has only 24 hours.

10+1 Things is a curated newsletter by Rishikesh featuring 11 interesting things handpicked from the vast universe of information.

I aim to deliver information you wouldn’t have seen otherwise in a digital world filled with bots and algorithms.

Every single article, research note, book or video is handpicked and is evaluated for factual accuracy.

10+1 Things is free and weekly, so subscribe if you’re interested!

⚡️P.S. If you're new here and want to read more of the Synapse Newsletter twice a month, subscribe below!⚡️