Showing papers in "Journal of Neurophysiology in 1955"

Response of single motoneurons to direct stimulation in toad's spinal cord.

Abstract: THE ACTIVITIES of single nerve cells explored with intracellular electrodes have been reported by several authors (1, 3, 4, 14). In those reports researches whether were made in connection with orthodromic or antidromic. It the excitation via neural is desirable, however, to pathways, adopt the method of direct stimulation in order to get more detailed knowledge concerning the physiological properties of the soma membrane. Since the insertion out ordinarily without of microelectrodes into the visual control, there is no neurons must be carried possibility of having two separate microelectrodes lodging in the same neuron, the one for stimulation and the other for recording. The use of a twin-microelectrode was also found inappropriate for the present purpose, because of the electrical interference between each electrode due to their capacitative coupling. The only method available was therefore to use the same microelectrode with certain compensation circuits for both stimulation and recording. The results reported here were obtained with such a method on single spinal motoneurons of Japanese toads.

Electric responses of individual nerve elements in cochlear nucleus to sound stimulation (guinea pig).

Abstract: IN A RECENT PAPER one of us (7) described the technique and the results of recording impulses from individual auditory nerve fibers in the modiolus of the guinea pig. The present investigation is an extension to the cochlear nucleus in the medulla oblongata of the same technique of recording action potentials with submicroscopic microelectrodes (6). Action potentials from single elements in the cochlear nucleus have already been successfully recorded by Galambos and Davis (2, 3, 4) with an earlier type of microelectrode. The original purpose of the present investigation was to repeat their previous observations with a finer technique. There is a certain difference in behavior between the elements examined in the present investigation and those studied previously. The “response area” of an element is the area on an intensity-frequency plot that includes all tones that evoke a positive response. The response areas of the new elements show a sharp limit on the high-frequency side and very gradual elevation of threshold on the low-frequency side. The elements studied previously had, on the contrary, fairly narrow response areas with a clear maximum of sensitivity for a certain frequency that was characteristic of the element under observation. The new and the previous elements behaved differently in one other aspect: spontaneous discharges of impulses in the new elements were not inhibited by the application of any pure tone, while in the previous elements some tones inhibited and other tones enhanced the spontaneous repetitive activity.