scholarly journals Adaptation in Skate Photoreceptors

1972 ◽  
Vol 60 (6) ◽  
pp. 698-719 ◽  
Author(s):  
John E. Dowling ◽  
Harris Ripps
Keyword(s):  
Dark Adaptation ◽  
Control Mechanism ◽  
Pigment Epithelium ◽  
Gain Control ◽  
Receptor Potential ◽  
Recovery Phase ◽  
Cell Discharge ◽  
Receptor Response ◽  
Full Complement ◽  
Background Fields

Receptor potentials were recorded extracellularly from the all-rod retina of the skate after the application of sodium aspartate. This agent suppresses the responses of proximal elements, but leaves relatively unaffected the electrical activity of the photoreceptors (a-wave) and pigment epithelium (c-wave). Since the latter develops too slowly to interfere with the receptor response, it was possible to isolate receptor potentials and to compare their behavior in light and dark adaptation with earlier observations on the S-potential, b-wave, and ganglion cell discharge. The results show that the photoreceptors display the full complement of adaptational changes exhibited by cells proximal to the receptors. Thus, it appears that visual adaptation in the skate is governed primarily by the photoreceptors themselves. Of particular interest was the recovery of sensitivity in the presence of background fields that initially saturate the receptor potential. Analysis of this recovery phase indicates that a gain-control mechanism operates within the receptors, at a distal stage of the visual process.

Suppression of cone-driven responses by rods in the isolated frog retina

1988 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
Cun-Jian Dong ◽  
Hao-Hua Qian ◽  
John S. McReynolds ◽  
Xiong-Li Yang ◽  
Yu-Min Liu
Keyword(s):  
Dark Adaptation ◽  
Visual Pigment ◽  
Pigment Epithelium ◽  
Signal Transmission ◽  
Receptor Potential ◽  
Response Sensitivity ◽  
Long Wavelength ◽  
Negligible Amount ◽  
Frog Retina ◽  
Time Courses

AbstractThe sensitivity of rod- and cone-driven responses was studied in the isolated frog retina during the period of rapid dark adaptation following a conditioning flash which bleached a negligible amount of visual pigment. Following a conditioning flash, cone-driven b-wave responses were first enhanced and then depressed. The time courses of the enhancement and subsequent depression of cone-drive responses varies greatly with the intensity and wavelength of the conditioning flash, but were identical when the conditioning' flashes were matched for equal excitation of 502 nm rods. These changes in cone-driven response sensitivity were correlated with the desensitization and recovery of rods following the conditioning flash. When signal transmission from rods to second-order cells was interrupted by the addition of L-glutamate, the conditioning flash did not produce the above-described enhancement and subsequent depression of long-wavelength receptor potential responses. The suppression of cone-driven response therefore appears to be due to a synaptically mediated influence from 502 nm rods which is maximal when the rods are in the dark-adapted state, with little or no contribution from 433 nm rods, and no involvement of the pigment epithelium.

scholarly journals S-Potentials in the Skate Retina

1971 ◽  
Vol 58 (2) ◽  
pp. 163-189 ◽  
Author(s):  
John E. Dowling ◽  
Harris Ripps
Keyword(s):  
Membrane Potential ◽  
Ganglion Cell ◽  
Dark Adaptation ◽  
Membrane Potentials ◽  
Horizontal Cells ◽  
Photic Stimulation ◽  
Visual Adaptation ◽  
Cell Discharge ◽  
Background Fields ◽  
Potential Level

The S-potentials recorded intracellularly from the all-rod retina of the skate probably arise from the large horizontal cells situated directly below the layer of receptors. These cells hyperpolarize in response to light, irrespective of stimulus wavelength, and the responses in photopic as well as scotopic conditions were found to be subserved by a single photopigment with λmax = 500 nm. The process of adaptation was studied by recording simultaneously the threshold responses and membrane potentials of S-units during both light and dark adaptation. The findings indicate that the sensitivity of S-units, whether measured upon steady background fields or in the course of dark adaptation, exhibits changes similar to those demonstrated previously for the ERG b-wave and ganglion cell discharge. However, the membrane potential level of the S-unit and its sensitivity to photic stimulation varied independently for all the adapting conditions tested. It appears, therefore, that visual adaptation in the skate retina occurs before the S-unit is reached, i.e., at the receptors themselves.

The Speed of Auditory Low-Side Suppression

2005 ◽  
Vol 93 (1) ◽  
pp. 201-209 ◽  
Author(s):  
Marcel van der Heijden ◽  
Philip X. Joris
Keyword(s):  
Traveling Wave ◽  
Auditory Nerve ◽  
Control Mechanism ◽  
Gain Control ◽  
Auditory Stimuli ◽  
Integration Time ◽  
The Difference ◽  
Cochlear Gain ◽  
Millisecond Accuracy ◽  
Group Delays

The nonlinear cochlear phenomenon of two-tone suppression is known to be very fast, but precisely how fast is unknown. We studied the timing of low-side suppression in the auditory nerve of the cat using multitone complexes as auditory stimuli. An evalution of the group delays of the responses to these complexes allowed us to measure the timing of the responses with sub-millisecond accuracy for a large number of fibers with characteristic frequencies (CFs) between 2 and 40 kHz. In particular, we measured the delays with which the same below-CF tone complexes affected the response either as an excitor (when presented alone) or as a suppressor (when combined with a CF probe). For CFs <10 kHz, we found that the delay of suppression was larger than the delay of excitation by several hundred microseconds. The difference between the delay of suppression and that of excitation decreased with increasing CF, becoming negligible for CFs >15 kHz. The results are analyzed in terms of traveling-wave delays and a purported cochlear gain control. The data suggest that suppression originates from a gain-control mechanism with an integration time in the order of two cycles of CF.

scholarly journals Retinal mechanisms of visual adaptation in the skate.

1975 ◽  
Vol 65 (4) ◽  
pp. 483-502 ◽  
Author(s):  
D G Green ◽  
J E Dowling ◽  
I M Siegel ◽  
H Ripps
Keyword(s):  
Ganglion Cell ◽  
Cell Activity ◽  
Receptor Potential ◽  
Visual Adaptation ◽  
Cell Discharge ◽  
Cell Responses ◽  
Electrical Potentials ◽  
Rate Of Recovery ◽  
Network Mechanism ◽  
Different Levels

Electrical potentials were recorded from different levels within the skate retina. Comparing the adaptive properties of the various responses revealed that the isolated receptor potential and the S-potential always exhibited similar changes in sensitivity, and that the b-wave and ganglion-cell thresholds acted in concert. However, the two sets of responses behaved differently under certain conditions. For example, a dimly iluminated background that had no measurable effect on the senitivities of either of the distal responses, raised significantly the thresholds of both the b-wave and the ganglion cell responses. In addition, the rate of recovery during the early, "neural" phase of dark adaptation was significantly faster for the receptor and S-potentials than for the b-wave or ganglion cell discharge. These results indicate that there is an adaptive ("network") mechanism in the retina which can influence significantly b-wave and gaglion cell activity and which behaves independently of the receptors and horizontal cells. We conclude that visual adaptation in the skate retina is regulated by a combination of receptoral and network mechanisms.

scholarly journals A Presynaptic Gain Control Mechanism Fine-Tunes Olfactory Behavior

Neuron ◽  
2008 ◽  
Vol 59 (2) ◽  
pp. 311-321 ◽  
Author(s):  
Cory M. Root ◽  
Kaoru Masuyama ◽  
David S. Green ◽  
Lina E. Enell ◽  
Dick R. Nässel ◽  
...  
Keyword(s):  
Control Mechanism ◽  
Gain Control ◽  
Olfactory Behavior

scholarly journals Evidence for a noise gain control mechanism in human vision

1998 ◽  
Vol 38 (13) ◽  
pp. 1925-1933 ◽  
Author(s):  
Lawrence G Brown ◽  
Michael E Rudd
Keyword(s):  
Control Mechanism ◽  
Gain Control ◽  
Human Vision

scholarly journals Adaptation in the Ventral Eye of Limulus is Functionally Independent of the Photochemical Cycle, Membrane Potential, and Membrane Resistance

1973 ◽  
Vol 61 (3) ◽  
pp. 273-289 ◽  
Author(s):  
A. Fein ◽  
R. D. DeVoe
Keyword(s):  
Membrane Potential ◽  
Time Constant ◽  
Dark Adaptation ◽  
Light Adaptation ◽  
Receptor Potential ◽  
Membrane Resistance ◽  
Initial Time ◽  
Early Receptor Potential ◽  
Time Courses ◽  
Sensitivity Changes

The early receptor potential (ERP), membrane potential, membrane resistance, and sensitivity were measured during light and/or dark adaptation in the ventral eye of Limulus. After a bright flash, the ERP amplitude recovered with a time constant of 100 ms, whereas the sensitivity recovered with an initial time constant of 20 s. When a strong adapting light was turned off, the recovery of membrane potential and of membrane resistance had time-courses similar to each other, and both recovered more rapidly than the sensitivity. The receptor depolarization was compared during dark adaptation after strong illumination and during light adaptation with weaker illumination; at equal sensitivities the cell was more depolarized during light adaptation than during dark adaptation. Finally, the waveforms of responses to flashes were compared during dark adaptation after strong illumination and during light adaptation with weaker illumination. At equal sensitivities (equal amplitude responses for identical flashes), the responses during light adaptation had faster time-courses than the responses during dark adaptation. Thus neither the photochemical cycle nor the membrane potential nor the membrane resistance is related to sensitivity changes during dark adaptation in the photoreceptors of the ventral eye. By elimination, these results imply that there are (unknown) intermediate process(es) responsible for adaptation interposed between the photochemical cycle and the electrical properties of the photoreceptor.

scholarly journals An early gain-control mechanism in binocular combination

2010 ◽  
Vol 6 (6) ◽  
pp. 832-832 ◽  
Author(s):  
G. Sperling ◽  
J. Ding
Keyword(s):  
Control Mechanism ◽  
Gain Control
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