  Redundancy is a ubiquitous property of the nervous system. This means that
vastly different configurations of cellular and synaptic components can enable
the same neural circuit functions. However, until recently very little brain
disorder research considered the implications of this characteristic when
designing experiments or interpreting data. Here, we first summarise the
evidence for redundancy in healthy brains, explaining redundancy and three of
its sub-concepts: sloppiness, dependencies, and multiple solutions. We then lay
out key implications for brain disorder research, covering recent examples of
redundancy effects in experimental studies on psychiatric disorders. Finally,
we give predictions for future experiments based on these concepts.
