Electrically induced Fos-like immunoreactivity in the auditory pathway of the rat: Effects of survival time, duration, and intensity of stimulation

• Published in: Brain research bulletin 1996, Vol.39 (2), p.75-82
• Main Authors: Zhang, J.S., Haenggeli, C.A., Tempini, A., Vischer, M.W., Moret, V., Rouiller, E.M.
• Format: Article
• Language: English
• Subjects: Action Potentials - physiology; Animals; Auditory Pathways - anatomy & histology; Auditory Pathways - metabolism; Auditory Pathways - physiology; Biological and medical sciences; c- fos; Cochlear implant; Cochlear Implants; Cochlear nucleus; Cochlear Nucleus - metabolism; Cochlear Nucleus - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Electric Stimulation; Female; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; Inferior Colliculi - metabolism; Inferior Colliculi - physiology; Inferior colliculus; Male; Medial geniculate body; Proto-Oncogene Proteins c-fos - metabolism; Rats; Rats, Sprague-Dawley; Survival; Thalamic Nuclei - metabolism; Thalamic Nuclei - physiology; Vertebrates: nervous system and sense organs; Vestibular Nuclei - metabolism; Vestibular Nuclei - physiology
• ISSN: 0361-9230; 1873-2747
• DOI: 10.1016/0361-9230(95)02053-5

The goal of the present study was to establish how Fos-like immunoreactivity (FLI) elicited in the rat auditory pathway by unilateral electric stimulation of the cochlea is affected by the following experimental parameters: duration and intensity of stimulation, duration of survival time after offset of stimulation. The dense FLI found in the ipsilateral dorsal cochlear nucleus, as well as the moderate FLI found in the contralateral dorsal cochlear nucleus and in the posteroventral cochlear nucleus on both sides, were consistent after survival times ranging from 0 to 2–3 h, but they significantly decreased after longer survival times (5 and 6 h). In the same nuclei, FLI was increased even by short durations of stimulation (5 and 10 min) as compared to control rats, although FLI progressively increased for longer stimulation (20 and 45 min). In the auditory thalamus, FLI was found mainly in the peripeduncular nucleus, the dorsal and medial divisions of the medial geniculate body, whereas its ventral division was virtually devoid of immunoreactive neurons. This pattern of FLI distribution in the auditory thalamus persisted even after relatively long survival times (5 and 6 h). In both the cochlear nucleus and auditory thalamus, the density of FLI slightly increased in parallel with the intensity of stimulation. In other auditory nuclei, such as the inferior colliculus and the nucleus of the lateral lemniscus, there was no simple relation between the density of FLI and the three tested experimental parameters. Thus, the distribution and density of FLI did not vary in parallel in the various nuclei of the auditory pathway as a function of the tested experimental parameters; different patterns of FLI changes were instead observed in different auditory nuclei.