“We found a synapse approximately every cubic micron,” Lichtman said. “That means if you look at images of the brain captured using high-resolution techniques like functional magnetic resonance imaging, where the pixel size represents one cubic millimeter, then there are one billion synapses within every pixel.”
It may be there, in that staggering density, he said, that the study’s final message lies.
“It’s very hard to get a complete feeling for this,” Lichtman said. “There is this naïve view that if you just know a little bit more, then understanding it will be easier, but in this case, knowing a little more has shown us how much further we have to go before we’ll understand brains.”