Voltage signal of photoreceptors at visual threshold

Fain, Gordon; Granda, A.M.; Maxwell, James

doi:10.1038/265181a0

Cited by 39 publications

(20 citation statements)

References 13 publications

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“…If hair cells, like photoreceptors, can synaptically transmit statistically significant signals corresponding to 10 ,tV receptor potentials (19), the threshold sensitivity of the amphibian sacculus would approximate 500 pm (5 A). Von Bekesy estimated the movement of the basilar membrane of the human cochlea (approximately equal to bundle displacement) at 1 pm at auditory threshold (20).…”

Section: Discussionmentioning

confidence: 99%

Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli.

Hudspeth¹,

Corey²

1977

Proc. Natl. Acad. Sci. U.S.A.

636

328

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Hair cells, the primary receptors of the auditory, vestibular, and lateral-line sensory systems, produce electrical signals in response to mechanical stimulation of their apical hair bundles. We employed an in vitro preparation and intracellular recording to investigate the transduction mechanism of hair cells in the sacculus from the inner ear of the bullfrog (Rana catesbeiana). When Hair cells respond with small receptor potentials (1, 2) which evidently excite afferent nerve fibers by chemical (3) or electrical synapses.The transduction process by which bending of the hair bundle elicits an electrical response is poorly understood because hair cells are generally small, relatively inaccessible, and difficult to impale with intracellular microelectrodes. Moreover, because the cells in situ are stimulated through the mechanical and hydrodynamic linkages that couple their hair bundles to vibrations in the external medium, the exact nature of the mechanical stimuli delivered to the cells is unknown in every instance. We have circumvented these difficulties by developing an in vitro preparation which permits intracellular recording from relatively large hair cells during the delivery of precisely defined stimuli directly to their hair bundles.MATERIALS AND METHODS Experimental Preparation. The hair cell preparation was taken from the sacculus of the bullfrog (Rana catesbeiana); this organ of the inner ear responds to ground-borne vibrations (4) and perhaps to sound (5). The macula, a discoidal region of the saccular wall in which the hair cells are situated (6), was rapidly dissected from the labyrinth by a ventral surgical approach. After the otoconia (otoliths) within the sacculus were rinsed away with a gentle stream of standard saline solution, the transparent otolithic membrane that overlies the macula was carefully peeled away with fine forceps.

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Section: Discussionmentioning

confidence: 99%

Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli.

Hudspeth¹,

Corey²

1977

Proc. Natl. Acad. Sci. U.S.A.

636

328

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“…Other cells that have been shown to signal post-synaptic cells with small voltage changes include rods and cones of the vertebrate retina (Baylor & Fettiplace, 1976;Ashmore & Falk, 1976;Fain, Granda & Maxwell, 1977) stretch receptors of the crab (Ripley, Bush & Roberts, 1968;Bush & Cannone, 1973) and oscillating pace-makers in arthropod ganglia (Mendelson, 1971;Pearson & Fourtner, 1975 (Shaw, 1972). All of these cells pose similar problems in synaptic physiology.…”

Section: Discussionmentioning

confidence: 99%

Voltage sensitive calcium channels in the presynaptic terminals of a decrementally conducting photoreceptor

Ross

Stuart

1978

The Journal of Physiology

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5. The action potential is followed by a large undershoot which can last several seconds. The amplitude and duration of the action potential and the duration of the undershoot all grow in increasing concentrations of TEA up to 400 mm, the highest concentration tested. The threshold for the action potential decreases as the concentration of TEA is increased to 10 mM; increasing the concentration further has no effect on the threshold. These observations suggest that TEA blocks a voltagesensitive potassium conductance at low concentrations but has less effect on the current responsible for the undershoot.6. Electrophysiological and pharmacological evidence suggests that the Ca channels are concentrated in the presynaptic terminals of this photoreceptor.

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“…Clearly, when the task and the conditions of the experiment are arranged appropriately, much smaller sensory signals can mediate behavior at threshold. And Fain, Granda, and Maxwell (1977) reported a threshold receptor potential in the turtle that is more than three orders of magnitude smaller in amplitude and probably (although there is no direct evidence) two orders of magnitude smaller in duration. Nevertheless, the behavioral sensitivities are fairly comparable, for Limulus achieves its high sensitivity through extensive temporal summation, while the turtle probably achieves its high sensitivity through extensive spatial summation.…”

Section: Threshold Receptor Potentialsmentioning

confidence: 98%

Limulus psychophysics: Increment threshold

Wasserman

1981

Perception & Psychophysics

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Prior temporal summation work had indicated that the sensory code for certain behaviors (in both Limulus and humans) can be understood if one suggests that the central nervous system analyzes the integral of the photoreceptor potential. An independent test of this suggestion is available because (in Limulus) the physiological increment threshold function obtained from the receptor potential integral is inflected, whereas that obtained from the initial transient peak of the receptor potential is not. The behavioral increment threshold function was measured in Limulus and found to be inflected. Fechner's scaling assumption (that equally detectable stimulus increments are mediated by sensory signals of equal size) was supported by the fact that a theoretical function, which was calculated from the receptor integral intensity-response function by using Fechner's scaling assumption, was able to fit the behavioral increment threshold function quite well. Furthermore, the variability of the behavioral data was proportional to the receptor integral variability. A seasonal effect was observed: Fall animals were more sensitive and had a higher criterion than winter animals. These findings permit the specification of the rerceptor potential that mediates this particular behavior at threshold: It has a steady-state amplitude of 7 mY in winter and 16 mY in fall. Taken in conjunction with the results of earlier temporal summation work indicating that the threshold receptor potential is 4.5 sec long, this specification implies that at least some behaviors are mediated by large, long sensory signals, which have properties very different from those of small, short signals, particularly with regard to both linearity and their relative dependence on time vs. energy.

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Voltage signal of photoreceptors at visual threshold

Cited by 39 publications

References 13 publications

Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli.

Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli.

Voltage sensitive calcium channels in the presynaptic terminals of a decrementally conducting photoreceptor

Limulus psychophysics: Increment threshold

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