Abstract
A description of the current to frequency conversion of extraocular neurons is presented. The discharge frequency of extraocular motoneurons of the cat to intracellular stimulation is rate sensitive to both depolarizing and hyperpolarizing current waveforms. From a time domain analysis of the relationship between the stimulus input current and the mathematically described measured neuronal discharge rate, the system impulse response is obtained by deconvolution. The description includes two non-linearities 1) a threshold element and 2) a current saturation element. The output of the derived process description is compared to experimental observations, evoked by a variety of current waveforms. The rate sensitive behaviour of extraocular motoneurons is demonstrated by a graph of gain versus the modulation frequency of stimulus current. It is suggested that the high frequency gain characteristic of the system partially compensates for the low pass transfer property of the extraocular muscles and orbital tissues. Thus the adaptive characteristics of these neurons could generate the neural signal necessary for the occurrence of saccadic eye movements.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Alpern,M.: Types of movement. In: Dawson,H. (Ed.): The eye, Vol. 3, pp. 65–174. New York: Academic Press 1969
Bach-y-Rita,P.: Neurophysiology of eye movements. In: Bach-y-Rita,P., Collins,C.C., Hyde,J.E. (Eds.): The control of eye movement, pp. 7–45. New York: Academic Press 1971
Barmack, N.H.: The frequency response of extraocular motoneurons to intracellular stimulation. (Abstract) Second Annual Meeting of Society for Neuroscience, Houston (1972)
Barmack, N.H.: Saccadic discharges evoked by intracellular stimulation of extraocular motoneurons. J. Neurophysiol. (in press)
Collins,C.C.: Orbital mechanics. In: Bach-y-Rita,P., Collins,C.C., Hyde,J.E. (Eds.): The control of eye movement, pp. 283–325. New York: Academic Press 1971
Frank,F., Fuortes,M.G.F.: Accommodation of spinal motoneurons of cat. Arch. Ital. Biol. 98, 165–170 (1960)
Fuchs,A.F., Luschei,E.S.: Firing patterns of abducens neurons of alert monkeys in relationship to horizontal eye movements. J. Neurophysiol. 33, 382–392 (1970)
Keller,E.L., Robinson,D.A.: Absence of a stretch reflex in extraocular muscle of monkey. J. Neurophysiol. 34, 908–919 (1971)
Keller,E.L., Robinson,D.A.: Abducens unit behavior in the monkey during vergence movements. Vision Res. 12, 369–382 (1972)
Robinson,D.A.: The mechanics of human saccadic eye movement. J. Physiol. 174, 245–264 (1964)
Robinson,D.A.: Oculomotor unit behavior in the monkey. J. Neurophysiol. 33, 393–404 (1970)
Sasaki,K., Otani,T.: Accommodation in spinal motoneurons of the cat. Jap. J. Physiol. 11, 443–456 (1961)
Schiller,P.H.: The discharge characteristics of single units in the oculomotor and abducens nuclei of the unanesthetized monkey. Exp. Brain Res. 10, 347–362 (1970)
Skavenski,A.A., Robinson,D.A.: Role of abducens neurons in vestibuloocular reflex. J. Neurophysiol. 37, 724–739 (1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Daley, M.L., Barmack, N.H. The current-to-frequency conversion of extraocular motoneurons. Kybernetik 15, 39–45 (1974). https://doi.org/10.1007/BF00270758
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00270758