Lhx6 Delineates a Pathway Mediating Innate Reproductive Behaviors from the Amygdala to the Hypothalamus

• Published in: Neuron (Cambridge, Mass.) Vol. 46; no. 4; pp. 647 - 660
• Main Authors: Choi, Gloria B., Dong, Hong-wei, Murphy, Andrew J., Valenzuela, David M., Yancopoulos, George D., Swanson, Larry W., Anderson, David J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.05.2005; Elsevier Limited
• Subjects: Aggression - physiology; Aggressiveness; Amygdala - cytology; Amygdala - physiology; Animal behavior; Animal reproduction; Animals; Behavior, Animal; Brain; Cholera Toxin - metabolism; Conflict (Psychology); Control theory; Female; Gene expression; Glutamate Decarboxylase - metabolism; Green Fluorescent Proteins - metabolism; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Homeodomain Proteins - physiology; Hybridization; Hypothalamus - cytology; Hypothalamus - physiology; Immunohistochemistry - methods; In Situ Hybridization - methods; Isoenzymes - metabolism; LIM-Homeodomain Proteins; Male; Membrane Transport Proteins - metabolism; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Nerve Tissue Proteins - physiology; Neural Networks (Computer); Neural Pathways - physiology; Neurons; Odorants; Odors; Proteins - genetics; Proteins - metabolism; Proto-Oncogene Proteins c-fos - genetics; Proto-Oncogene Proteins c-fos - metabolism; Rodents; Sexual Behavior, Animal - physiology; Stilbamidines - pharmacokinetics; Stimulation, Chemical; Transcription Factors; Urine; Vesicular Glutamate Transport Protein 2
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2005.04.011

In mammals, innate reproductive and defensive behaviors are mediated by anatomically segregated connections between the amygdala and hypothalamus. This anatomic segregation poses the problem of how the brain integrates activity in these circuits when faced with conflicting stimuli eliciting such mutually exclusive behaviors. Using genetically encoded and conventional axonal tracers, we have found that the transcription factor Lhx6 delineates the reproductive branch of this pathway. Other Lhx proteins mark neurons in amygdalar nuclei implicated in defense. We have traced parallel projections from the posterior medial amygdala, activated by reproductive or defensive olfactory stimuli, respectively, to a point of convergence in the ventromedial hypothalamus. The opposite neurotransmitter phenotypes of these convergent projections suggest a “gate control” mechanism for the inhibition of reproductive behaviors by threatening stimuli. Our data therefore identify a potential neural substrate for integrating the influences of conflicting behavioral cues and a transcription factor family that may contribute to the development of this substrate.