Dopamine is not the “feel good” molecule (and the very concept of a feel good molecule is meaningless)

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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.

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In what format is information stored in the brain?

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:

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What is neuroplasticity?

I was asked this question on Quora:

Can you explain to a layman what neuroplasticity entails?

Neuroplasticity is the umbrella term for all of the brain’s mechanisms for learning and memory.

Since the average layperson already knows about learning and memory, I’m not sure whether there are any interesting implications.

Unless of course you are surprised that the brain is involved in learning and memory. Then the implications are vast. 🙂

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Is a memory a bunch of atoms? And does this mean we can transfer exact memories?

I was asked the following question on Quora.

Are specific memories just arrangements of atoms in our brains? Could you put certain molecules in someones head and give them an exact memory that you had?

Short answer: No.


Modern science has shown that every thing is an arrangement of atoms: neurons, apples, tables, rockets, asteroids, aardvarks… they are all made up of atoms.

The question now is this: is a memory a thing?

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No New Neurons? No Problem!

This answer was written in response to the following Quora question:

New research has found no neurogenesis in human adults, could this mean there is none or could it mean that neural stem cells are undetectable with the used techniques? What are your thoughts on this?

It’s good that you’re thinking of such things, since that is exactly what researchers themselves have to do, and what reviewers do. In order to show that the method works, there have to be adequate controls as part of the experiment.

And this is in fact the case. The paper would not have been published without controls.

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Perhaps neurogenesis doesn’t happen in adult humans?

A new study suggests that new neurons are not born very often in human adults.

Birth of New Neurons in the Human Hippocampus Ends in Childhood

“The lab’s new research, based on careful analysis of 59 samples of human hippocampus from UCSF and collaborators around the world, suggests new neurons may not be born in the adult human brain at all. The findings present a challenge to a large body of research which has proposed that boosting the birth of new neurons could help to treat brain diseases such as Alzheimer’s disease and depression. But the authors said it also opens the door to exciting new questions about how the human brain learns and adapts without a supply of new neurons, as in seen in mice and other animals.”

My labmates are all monkey neuroanatomists, and for years they have been skeptical about the neurogenesis narrative, particularly in primates. Another famous dissenter is Pasko Rakic. Read about his complaints in this Guardian article from 2012:

Does your brain produce new cells?

 

“The first rule of intelligence: Don’t talk about your intelligence”

That line is from an article in The Atlantic about how poor people are at self-assessment:

People Don’t Actually Know Themselves Very Well

“The first rule of intelligence: Don’t talk about your intelligence. It’s something you prove, not something you claim. As comedian Patton Oswalt quipped about humor, the only person who goes around saying “I’m funny” is a not-funny person. If you were really funny, you’d just make people laugh.”

To me this kind of thing is pretty obvious, but I guess some people really need to be reminded of it.

Here’s another paragraph with several important reminders, particularly for people who blather about intelligence and cognitive biases:

“This is why people consistently overestimate their intelligence, a pattern that seems to be more pronounced among men than women. It’s also why people overestimate their generosity: It’s a desirable trait. And it’s why people fall victim to my new favorite bias: the I’m-not-biased bias, where people tend to believethey have fewer biases than the average American. But you can’t judge whether you’re biased, because when it comes to yourself, you’re the most biased judge of all. And the more objective people think they are, the more they discriminate, because they don’t realize how vulnerable they are to bias.”