[adityab]

Computational Neuroscience student here.

Research of this nature requires reading the electrical spike trains of small sets of neurons (often even individual cells).

EEG will give you a measurement of the combined electric field of every single neuron that is active in the entire brain. You can use multiple electrodes and run machine learning algorithms to get a qualitative measure of a macroscopic chunk of brain activity. So, terrible spatial precision.

MRI gives you anatomical information.

fMRI gives an idea of blood flow in the brain (about millimeter precision which is also not good enough) which is a time-lagged (a few seconds) _response_ to sustained neural spiking in a region.

Think of it like this: The brain is a computational organ where there is very little hardware-software separation. We're not going to be able to patch the software (say, to treat paralysis) without patching the hardware (say, with implants)

[lostlogin]

The point of my comment was that getting good testing is surely easier on humans than monkeys. Actually going in has to happen at some point - why not do this on humans that have volunteered? Cellular level investigations are obviously important but getting a wire in somewhere is not going to happen at a level this small. It will be image guided surely. X-ray would by my guess and hopefully MR but that obviously has its complexities as MR with additional wires isn't that straight forward. A decent MR DTI can help when you want to know where the fibres go, but as you say, the hardware/software division isn't quite so clear with live things.

[adityab]

The point of my comment was that getting good testing is surely easier on humans than monkeys. Actually going in has to happen at some point - why not do this on humans that have volunteered?

1. Humans do volunteer and it does happen, but even with full consent, regulations will always be stricter on human experimentation than on animals.

2. We don't understand the brain very well and it is easy to make mistakes when working with neural tissue. The consequences of causing irreversible damage/death are much higher when the brain belongs to a human being. On the other hand, most people eat animals for pleasure.

Cellular level investigations are obviously important but getting a wire in somewhere is not going to happen at a level this small

It does happen, there exist small electrode array implants that can be placed in neural tissue to both induce (for example, cause sensations that one can feel) and read-out activity. Such implants are in fact used in some human subjects (there are issues such as development of scar-tissue however).

A decent MR DTI can help when you want to know where the fibres go, but as you say, the hardware/software division isn't quite so clear with live things.

Yeah, for neural interfacing a connectome is not enough, you need to work at the neural code level. Reading out each spike with full spatial resolution from a distance will probably never happen.

Believe me, neuroscientists do not enjoy the fact that invasive experimentation has to be performed on blameless animals; unfortunately it has to be done, unless people are willing to live with the level of understanding/treatments we have now and never move forward.

[lostlogin]

I think you may misunderstand me as I wasn't clear

"Cellular level investigations are obviously important but getting a wire in somewhere is not going to happen at a level this small It does happen, there exist small electrode array implants that can be placed in neural tissue to both induce (for example, cause sensations that one can feel) and read-out activity. Such implants are in fact used in some human subjects (there are issues such as development of scar-tissue however)."

What I mean - in a human subject the placement of any implant is not going to be guided by anything approaching a cellular level of imaging resolution. It will mostly use conventional radiological image guidance to get close and then measure electrical signals once close. Or is this in fact what you are saying?

Sorry about my formatting - phone.

[dharma1]

We need single neuron level mapping for any hope of a decent Brain-Computer Interface. Or even for really understanding how the brain works, in order to simulate it or progress in biologically inspired AI.

Neural lace looks promising. But wouldn't be the first to volunteer for one :)

http://www.nature.com/nmeth/journal/v13/n10/full/nmeth.3969....

Sidenote: I feel slightly uneasy about all this stuff.

On one level it is progressing our knowledge, but both the methods of the research (animal testing) and potential implications of deep human+machine symbiosis, combined with CRISPR on animals and humans, feel instinctively bad. It won't stop at curing disease.