Responses of frog vestibular neurons to combined temperature microstimulation of the semicircular canals.
The temperature microstimulation of the semicircular canal (heat bursts lasting about 2 sec with a peak amplitude of 0.5-5.0 degrees C) can be regarded as an analog of angular acceleration acting within the cavity of the given canal; the combination of temperature microstimulations targeted simultaneously on several canals can serve as a physical model of accelerated rotation having complex spatial characteristics. The recording of the activity of neurons of the vestibular nuclei of the frog (n = 278) in response to temperature microstimulation of the canals showed that 80% of the neurons have inputs from one to two canals and only 20% from three to six canals. The distribution of laterality was characterized by the predominance of ipsilateral inputs: 201 neurons (72.3%) had only ipsilateral inputs; 14 neurons (5%) had only contralateral inputs; 63 neurons (22.7%) had both inputs. The ipsilateral horizontal (67.6%) and the posterior (61.9%) were the most effective inputs; while among the contralateral, the posterior (21.2%) canals were the most effective; the least effective were the contralateral horizontal (8.6%) and the anterior (5.0%) canals. The presence of latent canal inputs (both excitatory and inhibitory) which showed up in combination with effective inputs was demonstrated.
Tsoi
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Laboratory of the Physiology of the Vestibular Apparatus, I.P. Pavlov Institute of Physiology, Academy of Sciences of the SSSR [AN SSSR], Leningrad.
Orlov
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IV
Bovk
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TV
D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000502:physiology; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology*; D010812:Physical Stimulation; D011896:Rana temporaria; D012665:Semicircular Canals / Q000502:physiology*; D013696:Temperature; D014726:Vestibular Nuclei / Q000033:anatomy & histology / Q000502:physiology; D014722:Vestibule, Labyrinth / Q000294:innervation*