Neuromorphic Buzzwords

Recent advances give theoretical insight into why deep learning networks are successful

Aug 2020, phys.org

https://techxplore.com/news/2020-07-advances-theoretical-insight-deep-networks.html

It's just like olfaction.

If you didn't know what a deep learning neural network was in 2015 when Hidden Scents came out, you do now. Face recognition? Deep learning. Speech recognition? Deep learning. Deep fakes?? You guessed it. 

But why would someone spend an entire chapter of a book on smell talking about brain-like computing systems? Because the little part of our brain that smells is about as close as you get to a deep learning neural network.

And the story goes like this -- Big data brings Dirty data, which then brings the curse of dimensionality. It's not like mammals->dogs->poodles. It's like "that dog that bit me one time" and "the kind of dog that likes kids" and "dogs that were selected to hunt rodents" and "coyotes" and "pet cemetary" and "totem poles." Imagine a spreadsheet that has just as many columns as it has rows. For every rule there's an exception. 

What you probably know as a "computer algorithm" is just a bunch of rules. But when every rule has an exception, algorithms don't work so good anymore. This is the curse of dimensionality. 

This is also the chemosphere being described. Chemicals are myriad and ever-changing. Any means of chemosensation will have to employ something closer to a deep learning network than to an old-fashioned computer algorithm of IF/THEN functions. And that's why our olfactory system could really be called the deep nose, and why olfaction will become the representative sense of the Age of Approximation born of the datapocalypse. 

This thought-provoking paper does a much better job describing these networks, and makes implications for their use in society:

Tomaso Poggio et al. Theoretical issues in deep networks, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.1907369117

Your Mother

Word.

Somewhere in England they are now programming smoke alarms with your mother's voice instead of an ear piercing siren, because it gets you out of bed quicker. The precious seconds saved could also save lives.

The reason the sound of your mother's voice can turn on your inner alarm faster than a fog horn, has a lot to do with our nature as social creatures, and of course, our limbic systems.

The limbic system is the part of us that takes flight in a dangerous situation. It is a brain inside our brain, and if it had a brain inside it, that would probably be the amygdala; I'm sure you've heard of it. It also holds the hippocampus, also known as the memory bank.

The limbic system operates beyond our conscious control. It has to, because it's a big part of what keeps us alive before we even become "conscious." It learns from its environment, and responds accordingly. A major part of that environment is the people around us.

Our status as social animals makes us very sensitive to the people around us, and especially those who take care of us, and especially even more those who take care of us when we're young.

This is because our limbic system is, shall we say, very open to suggestion when we're young. It's kind of like a blank slate of a book, or an instruction manual, where every word that's written starts out really big, and gets smaller and smaller as we age.

And who is one of the first people to write in this book? Your mother. She codes her voice so deep into your autonomic nervous system that the sound of it can activate your limbs faster than flash of lightning.

So it only makes sense that if we are looking for a shortcut to the body-control-system, this would be it.

Notes

Mum's voice makes better smoke alarm for children

Oct 2018, BBC

Robet Sapolski's Stanford lectures in Human Behavioral Genetics are a great place to learn about this kind of thing; he is a skilled and engaging lecturer.

Millions on prescription sleeping pills would sleep through a fire alarm
Jan 2019, phys.org

Post Script

Consider this idea in light of the developments we see today in robotics, or in any instance of digitally-mediated human assistance. Robots that take care of the elderly in the absence of their progeny, or who take care of people of reproductive age in the absence of a mate. The limbic system is a powerful thing, and it will certainly be exploited.

Post Post Script

Elon Musk did a surprisingly interesting job of describing all ^this in his infamous interview on the Joe Rogan show.

Post Post Post

Amygdalic is a word, but it doesn't do what you want it to in this context. It comes from chemistry and it means made of almonds, or rather the amygdalin contained therein. And now you got me started, almonds do also contain cyanide, but not enough to kill you, you robust biological specimen! If you ever had a rotten almond, you can pretend that's the cyanide in your mouth. Not totally sure about that, but there is another species of almond, actually called the bitter almond, that has more cyanide in it, and is also the almond used to make almond fragrance. The amygdala got its name because it is shaped like an almond.

Report From the Olfactory Hallucinations Department

Image source: Andrew McGibbon, Caiman, 2015 

Albeit “to smell” is about the closest we get to hallucinating, it’s always interesting to experience a glitch in the wiring. Driving back from the store, listening to music, I bought a bottle of perfume, sprayed my wrist, and headed home. Smells like white flowers, cardamom, and wood. Now, when I smell perfume, I basically expect that everything smells like everything. Fragrance is different from everyday smells in that you can never know what to expect. It could be anything in there, in some small amount, but for some reason, a part of you can zero-in on that one thing.

It’s not really hallucinating, but it is a huge distortion in one’s olfactory perception: So I’m listening to the intro, the build-up. And then the bass drops, and the drums come crashing in. And in that brief moment, right when it first drops, and when the adrenaline bursts to a peak, my nose picked out the musk, or something animal, and only for that one second. Sure it was there the whole time, artfully crafted and camouflaged into the blanket of others. But for that one second, the part-of-me-that-smells had zoned-in on that one molecule, and then gone.

I couldn’t pick it out again. Sure it‘s there, but it’s back in the blanket. Maybe if I skip to the next track…

The Triune Model

 The Reptile Brain, Illustration by Joe Scordo for the book Hidden Scents.

In my book Hidden Scents, I use the triune model to organize the explanation of a neurological model. The brain is complex, and I am not a scientist.

 Christel Quek via Paul MacLean: The "nose-brain" is everything besides the neocortex - it is both the limbic and the reptile brain. (And for disambiguation purposes - sometimes the term "reptile brain" includes the limbic system.)

However, there are ways of organizing the many inter-related parts of the brain that are technically inaccurate, yet hold explanatory power. The most well-known of these is the 'left-brain' 'right-brain' model. The 'left brain' is logical and the 'right brain' is emotional, one is lines and forms, the other shape and color. One is acute attention and the other a passive radar.

Although this model is useful in describing some of the most basic features of the brain as they relate to neuroanatomy, it only goes so far, and must be altered, edited and rearranged many times to reveal the intricate details of brain function.

Regarding olfaction, the triune brain model is useful in that it juxtaposes the critical characteristics of olfactory neuroanatomy against all other senses - that being its intimacy with the limbic system, the seat of our emotions and unconscious behavior.

Triune Brain

wiki

The triune model of the mammalian brain is seen as an oversimplified organizing theme by some in the field of comparative neuroscience*

It continues to hold public interest because of its simplicity. While technically inaccurate as an explanation for brain activity, it remains one of very few approximations of the truth we have to work with:

---the "neocortex" represents that cluster of brain structures involved in advanced cognition, including planning, modeling and simulation;

---the "limbic brain" refers to those brain structures, wherever located, associated with social and nurturing behaviors, mutual reciprocity, and other behaviors and affects that arose during the age of the mammals;

---and the "reptilian brain" refers to those brain structures related to territoriality, ritual behavior and other "reptile" behaviors.

The broad explanatory value makes this approximation very engaging and is a useful level of complexity for high school students to begin engaging with brain research.

*Smith CU., 2010, The triune brain in antiquity: Plato, Aristotle, Erasistratus. Journal of the History of the Neurosciences, 19:1-14. doi:10.1080/09647040802601605

Pre-Cognition

The Triune brain, a visualization of the evolution of the human brain. Illustration by Joe Scordo for Hidden Scents: The Language of Smell in the Age of Approximation

Parts of the primate brain are made to deal with any potential situation. The way these highly adaptive brain parts work are by using recurrent loops that interfere with each other, in what is being called a “reservoir” network.

Perhaps we see headlines written like this because artificial intelligence work is typically performed by first predicting all potential situations (that is, until recently, with the advent of ‘deep learning’ techniques). In other words, the idea that a brain, or part of a brain, is designed to deal not with predictable situations but novel ones, is counter to this prevailing predictive technique.

I’d like to make a link here between this adaptive behavior and the fact that our sense of smell is not pre-coded but a blank slate. We do not have pre-existing preferences for smells, and the pattern of olfactory receptors in the nose seem to have no discernable pattern whatsoever because they're meant to learn anew for every creature and for every situation. This is because the way we interact with our organic environment is so complex, there can’t be a set of rules that work for every potential situation.

Smell is part of the mammal brain, and not rational thinking is part of the human brain. (Note that the mammal brain is not the same as the primate brain, which is only used as a term here to disambiguate it from the human brain…semantics!) Granted, primates have a prefrontal cortex too, and we have learned that there is not as much difference as once thought between humans’ and other animals’ brains. Nonetheless, smell is the animal inside us, and a link to our evolutionary past, and to a world much less predictable than the one we inhabit today.

Post Script

The primate brain is 'pre-adapted' to face potentially any situation

phys.org, Jun 2016