the afferent connections of lateral septal area in the rat: hrp retrograde tracing technique

introduction: the septal region is part of the telencephalon and is a component of the limbic system. the lateral septal area (ls); largest nuclear mass in this region, plays a pivotal role in various physiological processes, such as aggression, emotion, thermoregulation, water and food intake and sexual behaviour. to support the functional analysis of this brain area in the rat, the sources of its afferents were determined using hrp retrograde tract tracing technique. materials and methods: one microliter of hrp (25%, sigma) injected by stereotaxic surgery and through hamilton syringe septum (ls) 48 hours after surgery. perfusion fixation and sectioning on animal brain, were performed. tmb histochemistry reaction using hrp was used for this purpose. results: retrogradely labeled perikarya was observed ipsilaterally in diagonal band of broca and hippocampus in telencephalon, paraventricular, parataenial, reuniens, lateroposterior, interanterodorsal and mediodorsal nuclei of the thalamus, lateral preoptic area, anterior and dorsal hypothalamus, lateral hypothalamus/tuber cinereum, perifornical area, posterior hypothalamus, submammillothalamic, supramammillary and lateral mammillary nuclei in diencephalon, ventral tegmental area, interfascicularis nucleus, interpeduncular nucleus, raphe nuclei, tegmental nuclei, central gray area and locus coeruleus in brain stem. conclusion: these results indicate that according to its connections, the ls is an integrative center that receives cognitive, behavioural and autonomic informations and probably is a center for modulating these informations.