Blanco, W.; Tabak, J.; Bertram, R.

The pulsatile activity of gonadotropin-releasing hormone neurons (GnRH neurons) is a key factor in the regulation of reproductive hormones. This pulsatility is orchestrated by a network of neurons that release the neurotransmitters kisspeptin, neurokinin B, and dynorphin (KNDy neurons), and produce episodic bursts of activity driving the GnRH neurons. We show in this computational study that the features of coordinated KNDy neuron activity can be explained by a neural network in which connectivity among neurons is modular. That is, a network structure consisting of clusters of highly-connected neurons with sparse coupling among the clusters. This modular structure, with distinct parameters for intracluster and intercluster coupling, also yields predictions for the differential effects of the co-released transmitters neurokinin B and dynorphin. In particular, it provides one possible explanation for how the excitatory neurotransmitter neurokinin B and the inhibitory neurotransmitter dynorphin can both increase the degree of synchronization among KNDy neurons.