scholarly journals The photometric matching field. —II. The effect of peripheral stimulation of the retina on the contrast sensibility of the fovea

1925 ◽  
Vol 98 (690) ◽  
pp. 353-353 ◽  
Keyword(s):  
White Light ◽  
Wave Length ◽  
Peripheral Stimulation ◽  
Retinal Rods ◽  
Contrast Perception ◽  
Matching Field ◽  
Stimulation Of

A previous paper showed that peripheral stimulation of the retina with white light may cause a reduction in the limen of contrast perception at the fovea. The present paper extends the investigation to monochromatic lights, using the same wave-length in centre and surround. Initial reductions followed by a rise in the limen are found with increasing brightness of surround at all wave-lengths, but the reductions are small in the red as compared with the blue end of the spectrum. The effects may be partly due to reflex actions associated with the retinal rods.

scholarly journals The photometric matching field. — II. The effect of peripheral stimulation of the retina on the contrast sensibility of the fovea

1925 ◽  
Vol 108 (747) ◽  
pp. 483-500 ◽  
Keyword(s):  
White Light ◽  
Focal Plane ◽  
Wave Length ◽  
Monochromatic Light ◽  
Peripheral Stimulation ◽  
Brass Plate ◽  
Contrast Perception ◽  
Matching Field ◽  
Different Parts ◽  
Stimulation Of

A paper by one of us has shown that peripheral stimulation of the retina with white light is capable of causing a considerable reduction in the limen of contrast perception at the fovea when the brightness of the central matching field is approximately equal to that of the surround. The present paper describes the extension of the work to include investigations of the effects when the wave-length of approximately monochromatic light illuminating the fields was varied throughout the spectrum, and also when the intensity of the surround was varied while that of the centre remained constant. In all cases the wave-length was the same in the centre as in the surround. The Apparatus. A plan of the apparatus employed is shown in fig. 1. A Nutting photometer was used in conjunction with a Hilger wave-length spectrometer to provide the central tripartite matching field. The shutter eyepiece of the spectrometer was replaced by a thin brass plate F, about 5 cm. square, with a small rect­angular aperture in the centre. This was placed in the focal plane of the lens L 3 , the position of the plate being such that the wave-length of the light from the centre of the hole was indicated by the wave-length drum of the spectrometer. The height and width of the aperture were 2.25 mms. and 1.25 mms. respectively. Fig. 2 shows the range of wave-lengths transmitted in different parts of the spectrum.

scholarly journals A case of abnormal trichromatic colour vision due to a shift in the spectrum of the green-sensation curve

1913 ◽  
Vol 89 (610) ◽  
pp. 232-245 ◽  
Keyword(s):  
White Light ◽  
Royal Society ◽  
Colour Vision ◽  
Wave Length ◽  
Electric Arc ◽  
Simple Spectrum ◽  
Normal Vision ◽  
Yellow Light ◽  
Colour Perception ◽  
Stimulation Of

The authors have each separately dealt with the question of complete and incomplete colour-blindness caused by the absence of, or decrease in, the response to stimulation of the red or green perceiving apparatus which is functional in the case of vision. We have shown that a large number of cases of defective perception of colour are simply explained on this hypothesis. Abnormality of colour vision may also be due to a shift in, or an alteration in form of, one of the sensation curves. In the present paper we discuss the effect of one type of shift on the colour perception and give the results of a series of measurements which show that such a shift, without any alteration of form, does sometimes occur. In a paper which appeared in the ‘Proceedings of the Royal Society,’ one of us indicated how a shift, that is a displacement of the whole curve so that the maximum is displaced to a different wave-length, of one of the sensation curves could be detected by a simple spectrum test, which is as follows. When yellow light of wave-length 5760 Å. U. is mixed with blue light of wave-length 4610 in suitable proportions the mixed light looks to the normal eye exactly the same as the white light from the crater of the electric arc both in hue and brightness. If a person who has a shift in one of the sensation curves is shown this match it will not appear correct to him nor can it be made correct by any alteration in the proportions of the yellow and blue lights. There will, however, in every case be found a position of the slit through which the yellow light is obtained with which a satisfactory match can be obtained. In other words the wave-length of the light which is complementary to the blue will be different to that of normal vision.

scholarly journals Peripheral Stimulation of the Saphenous and Superior Lateral Genicular Nerves for Chronic Knee Pain

Cureus ◽  
2021 ◽  
Author(s):  
Jamal Hasoon ◽  
Ahish Chitneni ◽  
Ivan Urits ◽  
Omar Viswanath ◽  
Alan D Kaye
Keyword(s):  
Knee Pain ◽  
Peripheral Stimulation ◽  
Chronic Knee Pain ◽  
Stimulation Of

THE REACTIONS OF THE HOUSEFLY, MUSCA DOMESTICA LINN., TO LIGHT OF DIFFERENT WAVE-LENGTHS

1938 ◽  
Vol 16d (11) ◽  
pp. 307-342 ◽  
Author(s):  
J. W. MacBain Cameron
Keyword(s):  
White Light ◽  
Copper Sulphate ◽  
Wave Length ◽  
Short Wave ◽  
Quantitative Relation ◽  
Copper Sulphate Solution ◽  
Quartz Mercury ◽  
Intensity Changes ◽  
Constant Quality ◽  
Colored Lights

Houseflies were reared on an artificial medium and tested with different wave-lengths of spectral light obtained from a quartz-mercury arc. The spectrum tested extended from λ3022 Å to λ5780 Å, and the lines were made of approximately equal intensity throughout. In addition, λ5461 Å and λ4078 Å were tested at several other intensities. The comparison standard in all cases was white light, obtained from a tungsten-filament, inside-frosted bulb, and filtered through copper sulphate solution. It was of constant quality, and the intensity was varied by changing the size of the bulb and by varying the distance from the bulb to the copper sulphate filter. The lighted areas to which the flies reacted were 5 by 10 mm. On one of these fell a total intensity of colored light of approximately 10.3 microwatts, on the other a range of intensity of white light of from 0.34 to 36.1 μw.Flies to be tested were removed from the breeding cage ten hours before tests began and were kept in darkness until used. Each fly whose record was used in compiling the final results was caused to make ten trips towards the two test lights, and a record was kept of the choice on each trip.A description and discussion of the four different methods found in the literature for conducting experiments of this type, and for analyzing the results, are included. In the first method, the intensity of the test light of a given wave-length is kept constant, while that of the standard light, usually white, is varied until both are equally attractive.The second method involves testing the colored light against a fixed intensity of white and finding the ratio of insects attracted to color. The intensity of white that will give the same ratio of attractiveness when tested against the standard is then determined.In the third method, the two test lights are made equal in intensity, and their relative efficiency is considered to be directly proportional to the number of insects attracted to each.In the last method, the standard is kept fixed in both quality and intensity, and the intensity of the test color is varied until the two are equal in attractiveness.Application of the first three methods to the same data shows that they give results that vary greatly as the intensity changes. Some show that efficiency increases as the intensity increases, while others show a decrease in efficiency with increasing intensity.If the intensities of all colored lights are equal, the three methods give practically the same qualitative results when applied to the same data. That is, a curve of efficiency is found which has its peak at the same wave-length, whatever method is used. Quantitatively, the results given by the three methods differ, so that no definite ratio of attractiveness can be determined between colors.The data obtained were not amenable to analysis by the fourth method, but published results indicate that this is perhaps the best method for determining the quantitative relation between the stimulative efficiencies of light of different colors.The housefly, M. domestica, is much more strongly stimulated by ultraviolet light of wave-length 3656 Å than by any other part of the spectrum examined. The effect decreases, at first rapidly and then more slowly, as the longer wave-lengths are reached; it also decreases on the short-wave side of the peak. The spectrum available extended only as far as λ3022 Å in the ultraviolet, at which point there was still an appreciable attractiveness, apparently greater than that of either yellow or green.Several problems are suggested that require further investigation.

Red Nucleus Stimulation Inhibits Within the Inferior Olive

1998 ◽  
Vol 80 (6) ◽  
pp. 3127-3136 ◽  
Author(s):  
K. M. Horn ◽  
T. M. Hamm ◽  
A. R. Gibson
Keyword(s):  
Inferior Olive ◽  
Red Nucleus ◽  
Salient Feature ◽  
Cutaneous Stimulation ◽  
Motor Pathways ◽  
Peripheral Stimulation ◽  
Dorsal Columns ◽  
Dorsolateral Funiculus ◽  
Somatosensory Responses ◽  
Stimulation Of

Horn, K. M., T. M. Hamm, and A. R. Gibson. Red nucleus stimulation inhibits within the inferior olive. J. Neurophysiol. 80: 3127–3136, 1998. In the anesthetized cat, electrical stimulation of the magnocellular red nucleus (RNm) inhibits responses of rostral dorsal accessory olive (rDAO) neurons to cutaneous stimulation. We tested the hypothesis that RNm-mediated inhibition occurs within the inferior olive by using stimulation of the ventral funiculus (VF) of the spinal cord in place of cutaneous stimulation of the hindlimb. Fibers in the VF terminate on hindlimb rDAO neurons, so inhibition of this input would have to occur within the olive. rDAO responses elicited by VF stimulation were inhibited by prior stimulation of the RNm, indicating that inhibition occurs within the olive. In contrast, evoked potentials recorded from the VF or dorsal columns following hindlimb stimulation were not affected by prior stimulation of RNm, indicating that stimulation of the RNm does not inhibit olivary afferents at spinal levels. RNm stimulation that inhibited rDAO responses had little effect on evoked somatosensory responses in thalamus, indicating that inhibition generated by activity in RNm may be specific to rDAO. To test limb specificity of RNm-mediated inhibition, conditioning stimulation was applied to the dorsolateral funiculus at thoracic levels, which selectively activates RNm neurons projecting to the lumbar cord. Stimulation at thoracic levels inhibited evoked responses from hindlimb but not forelimb regions of rDAO, suggesting that inhibitory effects of RNm activity are limb specific. Several studies have reported that olivary neurons have reduced sensitivity to peripheral stimulation during movement; it is likely that RNm-mediated inhibition occurring within the olive contributes to this reduction of sensitivity. Inhibition of rDAO responses by descending motor pathways appears to be a salient feature of olivary function.

scholarly journals Modulation and transmission of peripheral inputs in monkey cuneate and external cuneate nuclei

2011 ◽  
Vol 106 (5) ◽  
pp. 2764-2775 ◽  
Author(s):  
Claire L. Witham ◽  
Stuart N. Baker
Keyword(s):  
Peripheral Nerves ◽  
Action Potentials ◽  
Conditioning Stimulus ◽  
Mechanical Stimulus ◽  
Dorsal Column ◽  
Motor Threshold ◽  
Peripheral Stimulation ◽  
Transmission Of Information ◽  
Forelimb Afferents ◽  
Stimulation Of

Somatosensory signals undergo substantial modulation in the dorsal column nuclei. We examined transmission of signals from forelimb afferents in primate cuneate and external cuneate nuclei. In anesthetized macaque monkeys, the median, ulnar, deep radial, and superficial radial nerves were electrically stimulated at 1.5–2× motor threshold with independent Poisson trains whereas extracellular recordings were made from 317 cells. Responses to peripheral stimulation included instances of both brief facilitation and long lasting suppression. A high proportion of cells (87%) responded to stimulation of two or more peripheral nerves, suggesting a large amount of convergence. Facilitated cells showed coherence with the peripheral stimulation across a broad frequency range; coherence was especially high in cells that responded with a burst of action potentials. Cells that responded with suppression also showed significant coherence, but this fell rapidly for frequencies above 25 Hz. Similar results were seen in both the main and external cuneate. When stimulation of one nerve was conditioned by a preceding nerve stimulus, the response to the second stimulus was attenuated for around 40 ms. This occurred independently of whether the first stimulus produced an initial facilitation or suppression or whether the same or a different nerve served as a conditioning stimulus. Mechanical stimulation of a receptive field suppressed responses to a second identical mechanical stimulus over a similar timescale. We conclude that the primate cuneate nucleus is capable of transmitting temporal information about stimuli with high fidelity; stimuli interact both temporally and spatially to modulate the onward transmission of information.

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