  Downward causation is self-causation: the causal effect from the whole at the
macro level to its parts at the micro level, and is regarded as a solution to
the mind-body problem. However, no actual example of downward causation has not
been propsed. Here, we argue that a feedback control of micro-level neural
mechanisms using macro-level algebraic structure information between neural
network modules that is physically composed of neurons is a model of downward
causation in the brain. We speculate that downward causation causes
mathematical structure in our perceptual experience by controlling algebraic
structure in the brain.
