Determining how the brain stores information is one of the most pressing problems in
neuroscience. In many instances, the collection of stimuli for a given neuron can be modeled by
a convex set in
.
Combinatorial objects known as
neural codes can then be used to extract
features of the space covered by these convex regions. We apply results from
convex geometry to determine which neural codes can be realized by arrangements
of open convex sets. We restrict our attention primarily to sparse codes in low
dimensions. We find that intersection-completeness characterizes realizable 2-sparse
codes, and show that any realizable 2-sparse code has embedding dimension at most
. Furthermore,
we prove that in
and
,
realizations of 2-sparse codes using closed sets are equivalent to those
with open sets, and this allows us to provide some preliminary results
on distinguishing which 2-sparse codes have embedding dimension at most
.