Abstract: As experimental tools in neuroscience have advanced, measuring whole-brain dynamics with single-neuron resolution is becoming closer to reality. However, a task that remains technically elusive is to measure the interactions within and across brain regions that govern such system-wide dynamics. We propose a method to derive constraints on hard-to-measure neural network attributes --- such as inter-region synaptic strengths --- using easy-to-measure spiking statistics. As a test case, we studied interactions in the olfactory system. We used two micro-electrode arrays to simultaneously record from olfactory bulb (OB) and anterior piriform cortex (PC) of anesthetized rats who were exposed to several odors. We were able to make several predictions about the network, notably that inhibition within the OB and inhibition within PC were constrained to a narrow slice of possible values. As time permits, Iíll describe ongoing work in which we are applying the same techniques to determine how peripheral sensation and lateral inhibition combine to shape dynamic selectivity within the OB.