A top computer scientist discusses what the brain scientists get wrong.
Well, these are metaphors, which can be useful. Flows and pipelines are metaphors that come out of circuits of various kinds. I think in the early 1980s, computer science was dominated by sequential architectures, by the von Neumann paradigm of a stored program that was executed sequentially, and as a consequence, there was a need to try to break out of that. And so people looked for metaphors of the highly parallel brain. And that was a useful thing.
But as the topic evolved, it was not neural realism that led to most of the progress. The algorithm that has proved the most successful for deep learning is based on a technique called back propagation. You have these layers of processing units, and you get an output from the end of the layers, and you propagate a signal backwards through the layers to change all the parameters. It’s pretty clear the brain doesn’t do something like that. This was definitely a step away from neural realism, but it led to significant progress. But people tend to lump that particular success story together with all the other attempts to build brainlike systems that haven’t been nearly as successful.
Except the brain does do back propagation. And the chemicals that do the job of back propagation? Endocannabinoids.
Maybe that explains why he has never heard of them. Endocannabinoids are not common knowledge. A survey of medical schools offering courses in endocannabinoids got responses like these:
• Are you aware what type of institution we are? Why would we offer that here?
• The topic hasn’t gained enough traction or notoriety on this campus to be fully explored… Y’know what I mean?
• I have no idea what that is.
• You will have some very brief exposure to cannabinoid receptors and their effects in our curriculum.
• No course would touch upon this subject longer than five minutes.
• There are 12 mentions of cannabinoids in the curriculum database but no mention of the endocannabinoid system.
• We don’t teach anything like that at this school
• If it is mentioned, it is not a particular focus or talking point. I haven’t heard the endocannabinoid system come up in conversation.
• This is a school for people who want to become “doctors.”
• I never heard of it. We probably don’t teach it.
• Why are you asking that question? I don’t believe that’s an appropriate question. I wouldn’t waste other faculty member’s time with that question.
Lets see. You have more cannabinoid receptors in your body than any other type and it is not taught in medical school? Houston (and New York, and Chicago, and Berkeley, and Dallas, and…), we have a problem.
But you can help. Teach a doctor about endocannabinoids.