CV and abstract Christian Broberger - B·Debate

CVSPEAKER AT:Christian Broberger, M.D., Ph.D., Karolinska Institutet, Stockholm, Sweden.Dr. Broberger’s is an Associate Professor of Integrative Systems Neurobiology at theDept of Neuroscience, Karolinska Institutet. His research aims to elucidate thestructure and functional characteristics of neuronal circuits in the hypothalamus andits connections with the cerebral cortex that underlie basic survival functions such asreproduction, food intake and the transition between sleep and wakefulness. Thesequestions are pursued by a combination of slice electrophysiology and histochemistry.His laboratory is particularly interested in the cellular mechanisms that producerhythmic network activity with defined behavioural outputs and has recently describedsuch a rhythm in the neuroendocrine system that controls prolactin release andreproduction. Christian Broberger received his PhD in hypothalamic neuroanatomyunder the supervision of Tomas Hökfelt at Karolinska Institutet, and trained as apostdoctoral fellow in thalamocortical electrophysiology with David McCormick, YaleUniversity. His research has been recognized by a European Research Council StartingInvestigator Grant. Dr. Broberger is an inaugural member of the Young Academy ofSweden and was elected as its President in May, 2012.

ABSTRACTSPEAKER AT:Hypothalamic Circuit Interactions: Ready for Prime Time?Christian Broberger, M.D., Ph.D., Karolinska Institutet, Stockholm, Sweden.Harvey Cushing described the hypothalamus as “the mainspring of primitive existence …on which, with more or less success, man … has come to super-impose a cortex ofinhibitions”. Minute lesions to specific parts of this collection of nuclei cause dramaticchanges in phenotype: voracious eating, uninhibited sexual behavior and rage to name afew. Yet, despite its vital role in keeping us alive, well and reproducing, our understandingof the network interactions that produces hypothalamic output is still relatively primitive.Indeed, we have amassed a large catalogue of observations on the connectivity, transmitterexpression, cytoarchitectonics etc. of neurons. But in comparison with many other brainregions, such as the cerebral cortex and thalamus, we know relatively little about howelectrical properties and synaptic connections combine to produce network interactions inthe form of e.g. oscillations. Technical advances are now overcoming limitations in theform of cellular heterogeneity and limited anatomical accessibility of the hypothalamus,which have hampered out understanding. In our work, we have focused ontuberoinfundibular dopamine (TIDA) neurons, a neuroendocrine population that providestonic inhibition of pituitary prolactin release, constraining lactation to the nursing periodin the post-partum mother. In TIDA neurons, we have identified a robust 0.05 Hzoscillation, synchronized across the population through gap junctions. We propose thatchanges in discharge pattern, from e.g. phasic to tonic firing, serve to adjust dopamineoutput and, in turn, prolactin secretion, in tuning reproductive state. The role of individualconductances responsible for cellular and network behavior is now being dissected toprovide insight into the regulation of lactation in particular and neuroendocrine control ingeneral.