Will a full brain scanner be invented in the next 50 years?

[fredreload]

I've been looking into various brain scanners and there hasn't been one where it shows the brain at a molecular scale. I want a brain scanner that can perceive the flow of sodium and potassium in the brain as well as possibly all the neuronal synapses. I am not sure if such an invention is held back by ethical reasons, but right by all means it should be non invasive. MRI's scale is too big and you need an extremely powerful magnetic field to top that. PET scan requires you to dye the subject. My bet is on femtosecond and attosecond laser, but even then they require some fine tuning. Anyone got any idea on when a scanner of such a scale would be developed?

[EdEarl]

Estimated 10¹¹ neurons in a human brain. Estimated 10¹⁴ atoms in a human cell. About 60% of a human is water; thus, 10¹⁴ * 60% of the atoms are water molecules. The remaining 4*10¹³ atoms are other molecules of varying size, including DNA that contains about 2*10¹¹ atoms, but most molecules are considerably smaller.

 

Assumption (guess) 10⁹ molecules per cell means the brain would contain 10¹¹⁺⁹ = 10²⁰ molecules. You want flow of sodium and potassium, which means a video not a snapshot. A single frame would need a minimum of one pixel per molecule in low resolution 16 bits per pixel. That is 16 bits/pixel * 10²⁰ pixels per frame min * 10² frames/sec min * 10 seconds = 16*10²³ bits. Our biggest disks at this time are about 8 terabytes (8*10¹²). Thus, it would take 16*10²³/8*10¹² = 2*10¹¹ disks for 10 seconds of molecular video. I think that is a bit more than all the disk space sold to date.

 

I'd guess your desired technology is at least 10 years away, based only on required disk space.

 

I'm not an expert on scanners or microscopes, but the smallest things are imaged with an electron microscope that I believe would kill living tissue. An imaging technology such as you describe may never be possible, but there is always hope.

Edited June 27, 2016 by EdEarl

[CharonY]

Why do you dismiss existing instrumentation? Why do you think that size and/or tracers are limiting? How do you even think that lasers would be of any help (think in terms of penetration, volumes to be scanned, time frames, type of date, etc.). Why does the flow needs to be measured on the molecular scale in the first place?

[fredreload]

Why do you dismiss existing instrumentation? Why do you think that size and/or tracers are limiting? How do you even think that lasers would be of any help (think in terms of penetration, volumes to be scanned, time frames, type of date, etc.). Why does the flow needs to be measured on the molecular scale in the first place?

Hi, well the existing instrumentation does not show the brain in molecular detail as I want. The size is limiting because even the best MRI, as I found, cannot get brain image in molecular detail. Well an attosecond laser is able to observe the motion of an electron in detail so I thought it would be useful in observing molecular detail, that's speculation on my part. Well to observe the brain in a molecular scale helps understand the connection, memory, and function that makes up the brain

 

P.S. And I believe it grants digital immortality

Edited June 28, 2016 by fredreload

[CharonY]

You are switching between several orders of magnitude between and even within a sentence. Again what would a molecular resolution really tell you? Remind more again on wich scales neuronal connections are formed. Also try to visualize the change from tissue to cell, subcellular compartments, macromolecules, ions and atomic structure.

[fredreload]

Right, I'm focusing on the ions, you know, nerve impulse consists of sodium and potassium ions and that's precisely what I want to get a clear picture of. Not on an atomic level, by observing the flow of these ions I can hopefully get a general function of each of the neuron

Edited June 29, 2016 by fredreload

[CharonY]

In order to figure out where water flows in a system (even a small one) would you try to measure individual water molecules?

[fredreload]

If you do not look at the water pipe and leakage how do you know where it is broken, how do you know if it is water in there?

[CharonY]

So do you look at the leakage and pressure or at individual water molecules?

[fredreload]

So do you look at the leakage and pressure or at individual water molecules?

Well hmm, knowing that they are ions I probably wouldn't care as much because they are the same. Chemical synapse shouldn't matter much either. The flow is important because you need to know which function is activated, let it be hearing, visual, or other sense, each activates a different flow of the ions. Well, if you know circuitry better than me then you can tell me if the circuits exist in the brain is analogue of digital, last time I read somewhere both type of circuits exist in the brain. So to understand the flow you understand the functions of the circuits

[Strange]

Chemical synapse shouldn't matter much either.

 

 

The function of synapses is essential to the operation of the brain. Almost all changes in the state of consciousness are caused by changes to the function of the synapses.

[EdEarl]

 

 

The function of synapses is essential to the operation of the brain. Almost all changes in the state of consciousness are caused by changes to the function of the synapses.

Some fairy wasps, insects the size of a large amoeba, absorb the nucleus of neurons as they grow older; the nucleus is most of the soma (neuron central body). Essentially, some fairy wasps have neurons that consist only of an axon and dendrites that carry signals between synapses.

[EdEarl]

 

From super to ultra-resolution microscopy: New method pushes the frontier in imaging resolution -- Phys.org July 5, 2016

the advent of super-resolution microscopy that has allowed researchers to start visualizing closely positioned molecules or molecular complexes with 10-20 nanometer resolution is not powerful enough to distinguish individual molecular features within those densely packed complexes.

A water molecule is about 0.275 nm.

A neuron is about 100 nm, and an axon is about 20 nm diameter.

[CharonY]

Basically the issue is that in order to understand functions we need a larger picture of brain activities. Looking at individual cells or even molecules is only relevant if we want to figure out specific biochemical activities and interaction, but are not too interested in overall physiology. There is no easy way to bridge this particular gap. To put it differently, different resolution is used for different questions. If you want to look at brain activity you need something more like PET, MRI or equivalent and improved versions thereof. If want to go into high-resolution stuff once you are interested in cellular physiology or biochemical interactions.

[fredreload]

Basically the issue is that in order to understand functions we need a larger picture of brain activities. Looking at individual cells or even molecules is only relevant if we want to figure out specific biochemical activities and interaction, but are not too interested in overall physiology. There is no easy way to bridge this particular gap. To put it differently, different resolution is used for different questions. If you want to look at brain activity you need something more like PET, MRI or equivalent and improved versions thereof. If want to go into high-resolution stuff once you are interested in cellular physiology or biochemical interactions.

Right, it is the biochemical interactions we are looking into where we are tracing the sodium and potassium ions flow within the brain. Supposedly you heard a piece of music. How do you know which part of your brain is activated in listening to this piece of music? It could be the right brain, the left brain, or both. The only way to verify this is by tracing the ions flow within the neuron so we know which sensory neurons are being activated

[Strange]

This is what fMRI is used for, currently.

It can generally be narrowed down to much more than left or right. Very specific areas of the brain are involved in functions like that.

 

The other source of information is from people with various sorts of brain damage: seeing what functions are affected by damage in specific locations.

[CharonY]

Precisely. It even uses another proxy, i.e. blood flow as measure of neuronal activity. If you really measured ion flow on that scale you would end up with huge, non-interpretable data dumps as the changes are locally often not massive. Then we also got EEG, MEG, SPECT and so on. But as mentioned, and what you may now realize is that the overall activity is the important bit, not the tracking of individual molecules. Hence, there is no need (or use) of molecular resolution.