Gary Marcus wrote an excellent article for the New Yorker about what we actually know from neuroscience:
If most of the action in the brain lies at the level of neurons rather than voxels or brain regions (which themselves often contain hundreds or thousands of voxels), we may need new methods, like optogenetics or automated, robotically guided tools for studying individual neurons; my own best guess is that we will need many more insights from animal brains before we can fully grasp what happens in human brains. Scientists are also still struggling to construct theories about how arrays of individual neurons relate complex behaviors, even in principle. Neuroscience has yet find its Newton, let alone its Einstein.
The truth is our understanding of how the brain works is still very early, and that’s why neuroscience is so exciting right now: we are just beginning to understand a system that is overwhelmingly complex.