The hypothalamus is essential for our survival and orchestrates every vital function of the body, from defence against predators and energy metabolism to reproduction. Yet, the network mechanisms underlying these actions remain largely hidden in a black box . Here, we will focus on the hypothalamic neuroendocrine system, where we have identified a novel robust network oscillation in the tuberoinfundibular dopamine (TIDA) neurons that control prolactin release. This oscillation is synchronized between neurons via gap junctions, and phasic firing is transformed into tonic discharge by compounds that functionally oppose neuroendocrine dopamine actions. Using this novel preparation, we will investigate the 1) the cellular (conductance) and network (connectivity) mechanisms underlying TIDA rhythmicity; 2) how TIDA activity is affected by hormones and transmitters that affect lactation; 3) the functional significance of phasic vs. tonic discharge in the regulation of dopamine release and lactation; and 4) the generality of TIDA cellular and network properties to other parvocellular neuron populations. These questions will be addressed through several in vitro and in vivo electrophysiological techniques, including slice whole-cell recording, extracellular in vivo recording, voltammetry and optical recording. These experiments will provide novel insight into the link between network interactions and behaviour, and have important clinical implications for e.g. endocrine and reproductive disorders.