Shawn Mikula on Brain Preservation Protocols and Extensions

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Recently published article in Nature Methods on a new protocol for preserving mouse brains that allows the neurons to be traced across the entire brain, something that wasn't possible before. This is exciting because in as little as 3 years, the method could be extended to larger mammals (like humans), and pave the way for better neuroscience or even brain uploads. From the abstract:

Here we describe a preparation, BROPA (brain-wide reduced-osmium staining with pyrogallol-mediated amplification), that results in the preservation and staining of ultrastructural details throughout the brain at a resolution necessary for tracing neuronal processes and identifying synaptic contacts between them. Using serial block-face electron microscopy (SBEM), we tested human annotator ability to follow neural ‘wires’ reliably and over long distances as well as the ability to detect synaptic contacts. Our results suggest that the BROPA method can produce a preparation suitable for the reconstruction of neural circuits spanning an entire mouse brain

http://blog.brainpreservation.org/2015/04/27/shawn-mikula-on-brain-preservation-protocols/

Here we describe a preparation, BROPA (brain-wide reduced-osmium staining with pyrogallol-mediated amplification), that results in the preservation and staining of ultrastructural details throughout the brain at a resolution necessary for tracing neuronal processes and identifying synaptic contacts between them. Using serial block-face electron microscopy (SBEM), we tested human annotator ability to follow neural ‘wires’ reliably and over long distances as well as the ability to detect synaptic contacts. Our results suggest that the BROPA method can produce a preparation suitable for the reconstruction of neural circuits spanning an entire mouse brain

http://blog.brainpreservation.org/2015/04/27/shawn-mikula-on-brain-preservation-protocols/

In theory there is no difference between theory and practice. In practice there is.

A physical Turing machine can simulate an iPhone, in theory. Would you like to try to build one? :-D

The only problems would be speed and memory.

There is a tiny chance that when he said "does not reproduce the causal structure of neural interactions", what he actually meant was "would simulate the neural interactions extremely slowly", but if that was the case, he really could have said it better.

My priors are that when people without formal computer science education talk about brains and computers, they usually believe that parallelism is the magical power that gives you much more than merely an increase in speed.

2jacob_cannell11y

In practice it's just a matter of computational power. His statement makes it fairly clear that he doesn't understand this distinction. Circuit level simulations of advanced microchips certainly exist - this is not just theory. Yes they are super expensive when run on standard CPUs (real-time simulation of an iphone CPU naively would require on the order of an exaflop). However, low level circuit binary logic ops are much simpler than the 32/64 bit ops that CPUs implement, and there are more advanced simulation algorithms. Companies such as Cadence provide general purpose binary logic emulators that actually work, in practice for reasonable cost, not just theory.

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Shawn Mikula on Brain Preservation Protocols and Extensions

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Shawn Mikula on Brain Preservation Protocols and Extensions

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