Responses of nucleus reticularis tegmenti pontis neurons to vestibular stimulation in the rat.
Forty-nine neurons were recorded in the nucleus reticularis tegmenti pontis (NRTP) during horizontal vestibular and/or optokinetic stimulation in immobilized pigmented rats. During optokinetic stimulation, the response of NRTP neurons was either unidirectional (51%) or bidirectional (49%). Histological reconstruction showed that unidirectional neurons were located in the dorsal-medial part of NRTP, and bidirectional neurons in the lateral part. All neurons exhibited a response during pure vestibular sinusoidal stimulation in the frequency range 0.025 Hz-0.2 Hz. NRTP neurons were divided into two groups according to their threshold to vestibular stimulation. Group A neurons had a low threshold, a low spontaneous activity and their firing frequency slowly increased with acceleration. Group B neurons showed opposite characteristics. Phase and gain analysis suggested that NRTP neurons carry a head velocity signal. After hemiflocculectomy, the gain of the vestibular response of contralateral NRTP neurons increased. From these data, the role of NRTP in the horizontal vestibulo-oculomotor is discussed.
Le Taillanter
M
M
Université de Rouen, Laboratoire de Neurophysiologie Sensorielle, Faculté des Sciences, Mont Saint Aignan, France.
Lannou
J
J
D000200:Action Potentials; D000818:Animals; D009474:Neurons / Q000145:classification / Q000502:physiology*; D010775:Photic Stimulation; D011149:Pons / Q000502:physiology*; D051381:Rats; D012399:Rotation; D014722:Vestibule, Labyrinth / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*