Afferent and efferent connections of the interpeduncular nucleus with special refe...
| Grant number: | 12/02388-3 |
| Support type: | Regular Research Grants |
| Duration: | June 01, 2012 - May 31, 2014 |
| Field of knowledge: | Biological Sciences - Physiology - Physiology of Organs and Systems |
| Principal Investigator: | Martin Andreas Metzger |
| Grantee: | Martin Andreas Metzger |
| Home Institution: | Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| Assoc. researchers: | Chemutai Sego ; Leandro Bueno Lima |
Abstract
Aversive events impose a threat on brain and body homeostasis, creating a state known as stress. Pathological stress can lead to major depression and anxiety. Brain regions activated in stress involve on one hand telencephalic structures coping with the perception and coding of stress and on the other hand structures in the midbrain and mesopontine tegmentum modulating output systems that prepare the stress response. Interposed between these systems is the lateral habenula (LHb), a predominantly glutamatergic epithalamic structure, which receives major inputs from output structures of the basal telencephalon and projects to monoaminergic cell groups in the midbrain and mesopontine tegmentum. The LHb is selectively activated by aversive stimuli and predictive signals of negative errors and its basal activity is altered by physiological and pathological stress. The LHb exerts a profound inhibition over mesencephalic dopamine neurons, an effect mediated by a GABAergic relay in the mesopontine tegmetum, recently denominated rostromedial tegmental nucleus (RMTg). Interestingly, the RMTg also exerts a prominent inhibition over serotonergic neurons in the dorsal raphe nucleus (DR) and there is anatomical evidence that this effect is also mediated by the RMTg. However, almost nothing is known about the exact topography of RMTg projections to the DR and the neurotransmitters used by the projection neurons in the RMTg and target neurons in the DR. Postulating that the RMTg might be an important relay between the LHb and the DR we pretend to investigate in the present project using neuronal tracing techniques combined with immunohistochemical and in situ hybridization methods the exact topography and transmitter phenotype of the projections between the LHb, RMTg, and DR. (AU)