Inhibitory synaptic interactions between cochlear nuclei: Evidence from an in vitro whole brain study

• Published in: Neuroreport Vol. 10; no. 9; pp. 1913 - 1917
• Main Authors: Babalian, Alexander L, Ryugo, David K, Vischer, Mattheus W, Rouiller, Eric M
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins, Inc 23-06-1999; Lippincott Williams and Wilkins
• Subjects: Animals; Biological and medical sciences; Cell Size; Cochlear Nerve - physiology; Cochlear Nucleus - cytology; Cochlear Nucleus - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Electric Stimulation; Evoked Potentials, Auditory - physiology; Excitatory Postsynaptic Potentials - physiology; Fundamental and applied biological sciences. Psychology; Guinea Pigs; Neural Inhibition - physiology; Neurons - cytology; Neurons - physiology; Organ Culture Techniques; Reaction Time - physiology; Staining and Labeling; Synaptic Transmission - physiology; Vertebrates: nervous system and sense organs; Inhibitory postsynaptic potential; Electrical stimulus; Rodentia; Central nervous system; Cochlear nucleus; Electrophysiology; Auditory nerve; Isolated organ; Vertebrata; Mammalia; Guinea pig; Auditory pathway; Brain (vertebrata)
• ISSN: 0959-4965; 1473-558X
• DOI: 10.1097/00001756-199906230-00022

USING guinea-pig isolated whole brain preparation in vitro, synaptic responses to electrical stimulation of auditory nerves were examined in intracellularly recorded and stained neurons of posteroventral and dorsal divisions of the cochlear nucleus. Stimulation of the contralateral auditory nerve evoked exclusively IPSPs in 70% of neurons, with amplitude of 2.3 ± 1.2 mV. Neurons of all major cell types were inhibited from the contralateral side. In the majority of responding cells (78%) IPSPs were induced at latencies of 3–9 ms suggesting di- and trisynaptic connections from contralateral auditory afferents or, respectively, mono- and disynaptic connections from the contralateral cochlear nucleus. Few cells responded with long-latency IPSPs (13.5–23 ms), indicating involvement of polysynaptic pathways. These data demonstrate the existence of functional, direct and indirect inhibitory connections between the cochlear nuclei.