Much more complicated.
Neurons are complicated, but the basic functional concept is that synapses transmit electrical signals to the dendrites and cell body (input), and axons carry signals away (output). In one of many surprise findings, Northwestern University scientists have discovered that axons can operate in reverse: they can send signals to the cell body, too.
It also turns out axons can talk to each other. Before sending signals in reverse, axons can perform their own neural computations without any involvement from the cell body or dendrites. This is contrary to typical neuronal communication where an axon of one neuron is in contact with another neuron’s dendrite or cell body, not its axon. And, unlike the computations performed in dendrites, the computations occurring in axons are thousands of times slower, potentially creating a means for neurons to compute fast things in dendrites and slow things in axons.
Good work here, which, if it holds up, and proves true of all neurons, directly contradicts our current understanding of neural function, and expands exponentially the potential complexity of the human brain.
The meaning and utility of all this is not at all clear. The article makes the seemingly requisite, what-I-tell-you-three-times-is true observation that …
A deeper understanding of how a normal neuron works is critical to scientists who study neurological diseases, such as epilepsy, autism, Alzheimer’s disease and schizophrenia.
This has the flavour of the will o’ the wisp. To the extent that neurological diseases are collective, emergent phenomena, then a deeper understanding of how a normal neuron works will no more help us understand these diseases than studying individual water molecules will help us understanding convection currents or phase transitions.
“The thing can be done,” said the Butcher, “I think.
The thing must be done, I am sure.
The thing shall be done! Bring me paper and ink,
The best there is time to procure.”
“Taking Three as the subject to reason about—
A convenient number to state—
We add Seven, and Ten, and then multiply out
By One Thousand diminished by Eight.
“The result we proceed to divide, as you see,
By Nine Hundred and Ninety and Two:
Then subtract Seventeen, and the answer must be
Exactly and perfectly true.