Just came across a nice little article by Ed Yong on how the two major phases of sleep — REM and slow-wave sleep — might contribute to creativity. These ideas have been floating around for a while, but it’s nice to see them in a pop sci article.
(This is a cross-post of a 3 Quarks Daily article I wrote last year.)
A few months ago I attended a rather peculiar seminar at MIT’s Department of Brain and Cognitive Sciences. A neuroscientist colleague of mine named Robert Ajemian had invited an unusual speaker: a man named Jim Karol, who was billed as having the world’s best memory. According to his website, his abilities include “knowing over 80,000 zip codes, thousands of digits of Pi, the Scrabble dictionary, sports almanacs, MEDICAL journals, and thousands of other facts.” He has memorized the day of the week for every date stretching back to 1AD. And his abilities are not simply matter of superhuman willingness to spend hours memorizing lists. He can add new items to his memory rapidly, on the fly. After a quick look at a deck of cards, he can recall perfectly the order in which they were shuffled. I witnessed him do this last ‘trick’, as well as a few others, so I can testify that his abilities are truly extraordinary .
I was asked this question on Quora:
Here’s my answer:
It’s very difficult to define what exactly the will is in neuroscientific terms. It seems best to reserve this word for the whole organism, rather than some part of it.
Some philosophers would say that attributing will to some sub-component of an organism is an example of the “mereological fallacy”. It’s like saying the stomach eats, or the brain thinks, or the legs walk. We use these kinds of phrases as a kind of poetic shorthand, but only a complete organism can be said to eat, think, or walk.
In the case of the two hemispheres, we also know that the left brain right brain story — that one is “rational” and the other “holistic/artistic” — is wildly misguided. Some neural processes are, but most normal tasks that humans perform require close integration and communication between the hemispheres.
But we do have to make sense of a common experience — being “in two minds” about something. Most people know what it is like to be in a conflicted state — multiple goals or biases seem to be tugging at us. Clearly decision-making involves a sort of “parliamant” in the brain, in which multiple vested interests vie to enact legislation that suits them. 🙂
But the parliament metaphor should not be taken too seriously. There is little to be gained in anthropomorphizing neurons or groups of neurons. Neural ensembles might sometimes seem to behave as if they have a will, but that idea will not really help us understand decision-making, or the subjective feeling of having a will.
So brain areas don’t have likes or dislikes — organisms do, and brain areas mediate the processes by which these likes and disliked become manifest.
For more on the problems with anthropomorphizing neural processes, see these two essays I wrote:
(This essay is partly a gentle critique of the Pixar movie Inside Out.)
(This essay explores the tendency of people, including neuroscientists, to think of the brain is a separate agent from the person as a whole.)
I admit that it is often fun to anthropomorphize neurons, which is what I do in the essay below. I paint a picture of a neural city and a neural economy, complete with start-ups and investors. 🙂
I was asked this question on Quora:
Here’s how I responded:
Here’s a question: in a system composed of, is there a “code”?
I ask this because I find that the “code” metaphor is often misleading when thinking about biology. Codes are composed of symbols. But it is not clear that neurons communicate using symbols.
“In our world,” said Eustace, “a star is a huge ball of flaming gas.”
“Even in your world, my son, that is not what a star is but only what it is made of…”
The Voyage of the Dawn Treader, CS Lewis
I really like the quote above, which is from the Chronicles of Narnia. It raises a neat little metaphysical question:
Why do we assume that what a thing is made up of is what a thing is?
I really like the Yanny versus Laurel meme, which exploded yesterday. It helps illustrate some key points about human perception:
- In some situations people can differ wildly in their experience of low-level perception.
- Active top-down expectations (and other, weirder processes) have a strong effect on low-level perception.
So basically, it’s an auditory version of #ThatDress.
My research is on cognitive-emotional interaction, so I suppose I am qualified to answer this question. 🙂
But my answer cannot be the answer, since there is actually no consensus among scientists concerning the definition of emotions.
[Illustration of grief from Charles Darwin’s book The Expression of the Emotions in Man and Animals.]
Not really. But it’s a good question because we learn a lot when we try to answer it.
First, we have to clarify what the words ‘excitatory’ and ‘inhibitory’ mean.
- Excitation is the process by which a neuron’s membrane potential (or voltage) increases. If excitation is sufficient, a neuron will produce an action potential.
- Inhibition is the process by y which a neuron’s membrane potential (or voltage) decreases. If a neuron is already firing, then if it receives enough inhibition, it will stop firing.
So the statement “If some neurons are excitatory meaning they will fire and some inhibitory meaning they won’t” is not quite right. All neurons, whether excitatory or inhibitory, can fire, but only if they receive adequate excitation. If an inhibitory neuron fires, it can reduce the voltage of other neurons, whether they are excitatory or inhibitory. Excitation is the accelerator for all neurons. Inhibition is the brake for all neurons.
Dopamine is not the feel good molecule or the basis of pleasure. The idea that any molecule considered in isolation could be the basis of a subjective experience is basically nonsense.
For people who can’t really reason through this idea, there is plenty of experimental evidence showing the complexity of each and every “celebrity” neurochemical — dopamine, serotonin, oxytocin, and so on.
I was asked this question on Quora.
We don’t really know. But as one of my professors once said half-jokingly, “the brain is a bag of tricks”. There is no reason to assume that all brain regions use the same coding scheme.
Here are some basic concepts that guide how neuroscientists think about information in the brain: