NeuroethologySex differences in the vocal motor pathway of the zebra finch revealed by real-time optical imaging techniqueWang, Jian1; Sakaguchi, Hironobu2,3; Sokabe, Masahiro1,4Author Information 1Department of Physiology, Nagoya University School of Medicine, 65 Tsurumai, Nagoya 466-8550, Japan 2Department of Physiology, Dokkyo University, School of Medicine, Japan 3Intelligence and Synthesis, Precursory Research for Embryonic Science and Technology, Japan Science and Technology Corporation, Mibu, Tochigi 321-0293, Japan 4Corresponding Author: Masahiro Sokabe ACKNOWLEDGEMENTS: We thank Dr E. Hashino (SUNY/Buffalo) for critical reading and improving the manuscript. The work was supported by grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture (10680751 to H.S. and 1089802 to M.S.) and a grant for future studies from Japan Society for Promotion of Science (to M.S.). Received 2 June 1999; accepted 9 June 1999 NeuroReport: August 20, 1999 - Volume 10 - Issue 12 - p 2487-2491 Buy Abstract MALE zebra finches sing, whereas female zebra finches do not. To elucidate the neural mechanisms underlying sexual dimorphism in song behavior, the spatio-temporal properties of neural activity in the vocal motor pathway of the zebra finch were examined in sliced brain preparations using a real-time optical recording technique. Electrical stimulation to higher vocal center (HVC) fibers induced within 20 ms neural activities in the robust nucleus of the archistriatum (RA) of both male and female finches, although the amplitude was smaller and the latency was greater in females than in males. Bicuculline, a GABAA receptor antagonist, induced a robust activity in female RA, but had little effect in males. This suggests that neural connections from HVC to RA in female zebra finches are inhibited by GABAergic inputs. The results provide first evidence that an inhibitory neurotransmitter is involved in the sex difference in the motor vocal pathway of song birds. © 1999 Lippincott Williams & Wilkins, Inc.