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Articoli di riviste sul tema "Visual evoked response"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 28 luglio 2024

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1

Vaughan, Herbert G., e Robert Katzman†. "EVOKED RESPONSE IN VISUAL DISORDERS*". Annals of the New York Academy of Sciences 112, n. 1 (16 dicembre 2006): 305–19. http://dx.doi.org/10.1111/j.1749-6632.1964.tb26759.x.

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2

Douthwaite, W. A., e T. C. A. Jenkins. "VISUAL ACUITY PREDICTION USING THE VISUAL EVOKED RESPONSE". Ophthalmic and Physiological Optics 7, n. 4 (ottobre 1987): 421–24. http://dx.doi.org/10.1111/j.1475-1313.1987.tb00772.x.

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3

JENSEN, OLE LUND, e ERIK KROGH. "VISUAL EVOKED RESPONSE AND ALCOHOL INTOXICATION". Acta Ophthalmologica 62, n. 4 (27 maggio 2009): 651–57. http://dx.doi.org/10.1111/j.1755-3768.1984.tb03978.x.

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4

Vasile, Russell G., Frank H. Duffy, Gloria McAnulty, David Bear, John J. Mooney, Kerry Bloomingdale, Leslie K. Serchuck e Joseph J. Schildkraut. "Abnormal visual evoked response in melancholia". Biological Psychiatry 25, n. 6 (marzo 1989): 785–88. http://dx.doi.org/10.1016/0006-3223(89)90250-3.

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5

Katsumi, Osamu, Mehul C. Mehta, Elizabeth W. Larson-Park, Charlene J. Skladzien e Tatsuo Hirose. "Pattern reversal visual evoked response and Snellen visual acuity". Graefe's Archive for Clinical and Experimental Ophthalmology 232, n. 5 (maggio 1994): 272–78. http://dx.doi.org/10.1007/bf00194476.

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6

Kerty, Emilia, Nils Eide e Ola Skjeldal. "Visual evoked response in Syphilitic optic atrophy". Acta Ophthalmologica 64, n. 5 (27 maggio 2009): 553–56. http://dx.doi.org/10.1111/j.1755-3768.1986.tb06972.x.

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7

Granet, David B., Richard W. Hertle, Graham E. Quinn e Michael E. Breton. "The Visual-evoked Response in Infants With Central Visual Impairment". American Journal of Ophthalmology 116, n. 4 (ottobre 1993): 437–43. http://dx.doi.org/10.1016/s0002-9394(14)71401-1.

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8

Sanders, E. A., A. C. Volkers, J. C. van der Poel e G. H. van Lith. "Visual function and pattern visual evoked response in optic neuritis." British Journal of Ophthalmology 71, n. 8 (1 agosto 1987): 602–8. http://dx.doi.org/10.1136/bjo.71.8.602.

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9

Sedwick, Lyn A. "The Visual-Evoked Response in Infants With Central Visual Impairment". Journal of Neuro-Ophthalmology 14, n. 1 (marzo 1994): 63. http://dx.doi.org/10.1097/00041327-199403000-00035.

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10

Soelberg Sørensen, P., W. Trojaborg, F. Gjerris e B. Krogsaa. "Delayed visual evoked response in benign intracranial hypertension". Acta Neurologica Scandinavica 69, S98 (29 gennaio 2009): 389–90. http://dx.doi.org/10.1111/j.1600-0404.1984.tb02533.x.

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11

Douthwaite, W. A., e T. C. A. Jenkins. "Amplitude variability of the transient visual evoked response". Ophthalmic and Physiological Optics 8, n. 2 (aprile 1988): 221–26. http://dx.doi.org/10.1111/j.1475-1313.1988.tb01041.x.

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12

Baseler, H. A., E. E. Sutter, S. A. Klein e T. Carney. "The topography of visual evoked response properties across the visual field". Electroencephalography and Clinical Neurophysiology 90, n. 1 (gennaio 1994): 65–81. http://dx.doi.org/10.1016/0013-4694(94)90114-7.

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13

RUDVIN, INGER, ARNE VALBERG e BJØRG ELISABETH KILAVIK. "Visual evoked potentials and magnocellular and parvocellular segregation". Visual Neuroscience 17, n. 4 (luglio 2000): 579–90. http://dx.doi.org/10.1017/s0952523800174085.

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We have measured visual evoked potentials (VEPs) to luminance-modulated, square-wave alternating, 3-deg homogeneous disks for stimulus frequencies ranging from 1 Hz to 16.7 Hz. The aim of the study was to determine the range of frequencies at which we could reproduce the two-branched contrast-response (C-R) curves we had seen at 1 Hz (Valberg & Rudvin, 1997) and which we interpreted as magnocellular (MC) and parvocellular (PC) segregation. Low-contrast stimuli elicited relatively simple responses to luminance increments resulting in waveforms that may be the signatures of inputs from magnocellular channels to the visual cortex. At all frequencies, the C-R curves of the main waveforms were characterized by a steep slope at low contrasts and a leveling off at 10%–20% Michelson contrast. This was typically followed by an abrupt increase in slope at higher contrasts, giving a distinctive two-branched C-R curve. On the assumption that the low-contrast, high-gain branch reflects the responsivity of magnocellular-pathway inputs to the cortex, the high-contrast branch may be attributed to additional parvocellular activation. While a two-branched curve was maintained for frequencies up to 8 Hz, the high-contrast response was significantly compromised at 16.7 Hz, revealing a differential low-pass filtering. A model decomposing the measured VEP response into two separate C-R curves yielded a difference in sensitivity of the putative MC- and PC-mediated response that, when plotted as a function of frequency, followed a trend similar to that found for single cells. Due to temporal overlap of responses, the MC and PC contributions to the waveforms were hard to distinguish in the transient VEP. However, curves of time-to-peak (delay) as a function of contrast often went through a minimum before the high-contrast gain increase of the corresponding C-R curve, supporting the notion of a recruitment of new cell ensembles in the transition from low to high contrasts.

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14

Gareau, P. J., J. S. Gati, R. S. Menon, D. Lee, G. Rice, J. R. Mitchell, P. Mandelfino e S. J. Karlik. "Reduced visual evoked responses in multiple sclerosis patients with optic neuritis: Comparison of functional magnetic resonance imaging and visual evoked potentials". Multiple Sclerosis Journal 5, n. 3 (giugno 1999): 161–64. http://dx.doi.org/10.1177/135245859900500304.

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The limited application of functional magnetic resonance imaging (fMRI) for investigations of multiple sclerosis (MS) patients has already shown that deficits of the motor, cognitive and visual systems may be identified by differences in the patterns of activation in response to a suitable stimulus. In MS patients with unilateral optic neuritis, the area of activation in the primary visual cortex, measured by fMRI techniques, is dramatically reduced in response to stimulation of the affected eye. The latency of the major positive component of the visual evoked potential (VEP) recorded upon stimulation of the affected eye is significantly increased in these patients, as compared to the unaffected eye and normal volunteers. We have found a correlation between the neural response measured using fMRI and the latency of the VEP. fMRI signal responses have the potential to provide more detailed topographic information relating to functional deficits in MS.

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15

Kobayashi, Misa, e Makoto Ichikawa. "Emotional response evoked by viewing facial expression pictures leads to higher temporal resolution". i-Perception 14, n. 1 (gennaio 2023): 204166952311521. http://dx.doi.org/10.1177/20416695231152144.

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We examined the effects of emotional response, with different levels of valence and arousal, on the temporal resolution of visual processing by using photos of various facial expressions. As an index of the temporal resolution of visual processing, we measured the minimum lengths of the noticeable durations for desaturated photographs using the method of constant stimuli by switching colorful facial expression photographs to desaturated versions of the same photographs. Experiments 1 and 2 used facial photographs that evoke various degrees of arousal and valence. Those photographs were prepared not only in an upright orientation but also in an inverted orientation to reduce emotional response without changing the photographs’ image properties. Results showed that the minimum duration to notice monochrome photographs for anger, fear, and joy was shorter than that for a neutral face when viewing upright face photographs but not when viewing inverted face photographs. For Experiment 3, we used facial expression photographs to evoke various degrees of arousal. Results showed that the temporal resolution of visual processing increased with the degree of arousal. These results suggest that the arousal of emotional responses evoked by viewing facial expressions might increase the temporal resolution of visual processing.

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16

Alani, Shakir M. "Pattern-reversal visual evoked potentials in patients with hydrocephalus". Journal of Neurosurgery 62, n. 2 (febbraio 1985): 234–37. http://dx.doi.org/10.3171/jns.1985.62.2.0234.

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✓ Pattern-reversal visual evoked potentials (VEP's) in response to whole- and half-field stimulation were studied in 10 patients with hydrocephalus. Abnormalities consistent with optic nerve dysfunction were recorded in four patients. Two patients had response asymmetry to half-field stimulation, which suggested dysfunction of the visual pathway in the right hemisphere. The remaining four patients had normal responses. Measurement of VEP's was repeated after the surgical treatment of hydrocephalus in four patients, and showed marked improvement in two of the three patients with preoperative abnormalities. This study suggests that, in patients with hydrocephalus, VEP's are more sensitive than clinical methods in detecting visual pathway dysfunction and that they can be useful in the follow-up monitoring of surgically treated hydrocephalic patients.

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17

Shelepin, Y. E., A. K. Harauzov, N. N. Krasilnikov e S. V. Pronin. "Visual Evoked Potentials to Gratings and Noise". Perception 26, n. 1_suppl (agosto 1997): 355. http://dx.doi.org/10.1068/v970270.

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Visual evoked potentials were recorded in a study of the spatial-frequency characteristics of the human visual system. Stimuli were gratings with and without superposition of white noise. Evoked potentials were recorded in normal subjects from different areas of the occipital cortex, from the temporal and parietal lobes, according to the ‘ten-twenty’ electrode system. A set of black-and-white sine-wave gratings was used with eight different spatial frequencies in the range 0.45 to 14.4 cycles deg−1. The gratings were presented with binary quasi-white noise or with a uniform grey field with mean luminance equal to that of the noise. The amplitudes of the N1, P1, N2, and P2 response components were compared under the two stimulation conditions. Changes in the form of responses as well as changes in spatial-frequency characteristics were found when white noise was superimposed. The results obtained are discussed in terms of the presence and location of matched filtering in the visual system.

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18

MADDESS, TED, ANDREW C. JAMES, RASA RUSECKAITE e ELIZABETH A. BOWMAN. "Hierarchical decomposition of dichoptic multifocal visual evoked potentials". Visual Neuroscience 23, n. 5 (settembre 2006): 703–12. http://dx.doi.org/10.1017/s0952523806230013.

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Visual evoked responses to dichoptically presented multifocal stimuli were recorded for 92 eyes. Two stimulus variants were explored: temporally sparse and rapidly contrast reversing. We used hierarchal decomposition (HD) to represent the multifocal responses in terms of a small number of potentially unique component waveforms that are interrelated in a multivariate linear autoregressive (MLAR) relationship. The HD method exploits temporal correlations over a range of delays in the responses to estimate parallel, feedforward and feedback relationships between the HD components. Three HD components having temporal interrelationships constrained (at P < 0.05) to a moving ∼20 ms window could describe the multifocal responses well (median r2-values up to 90%). HD components were similar for both stimulus types and the component waveforms were temporally correlated, especially the first and third components. The data set was large enough to estimate separate HD components for each multifocal stimulus region. The component waveforms differed somewhat by region but the MLAR relationships were similar. At short delays parallel processing dominated. At longer delays the proportion of response drives that were attributed to feedback and feedforward relationships grew. Overall HD analysis seems to provide an informed summary of multifocal responses and insights into their sources.

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19

Hülsdünker, Thorben, Martin Ostermann e Andreas Mierau. "Motion-Onset Visual Potentials Evoked in a Sport-Specific Visuomotor Reaction Task". Journal of Sport and Exercise Psychology 42, n. 4 (1 agosto 2020): 280–91. http://dx.doi.org/10.1123/jsep.2019-0255.

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Although neural visual processes play a crucial role in sport, experiments have been restricted to laboratory conditions lacking ecological validity. Therefore, this study examined the feasibility of measuring visual evoked potentials in a sport-specific visuomotor task. A total of 18 international elite young table tennis athletes (mean age 12.5 years) performed a computer-based and a sport-specific visuomotor reaction task in response to radial motion-onset stimuli on a computer screen and table tennis balls played by a ball machine, respectively. A 64-channel electroencephalography system identified the N2 and N2-r motion-onset visual evoked potentials in the motion-sensitive midtemporal visual area. Visual evoked potential amplitudes were highly correlated between conditions (N2 r = .72, N2-r r = .74) although significantly lower in the sport-specific task than in the lab-based task (N2 p < .001, N2-r p < .001). The results suggest that sport-specific visual stimulation is feasible to evoke visual potentials. This emphasizes the investigation of visual processes under more ecologically valid conditions in sport and exercise science.

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20

Kothari, Ruchi, Ramji Singh, Smita Singh e Benhur Premendran. "Abnormal pattern visual evoked response in carotid-cavernous fistula". Journal of Neurosciences in Rural Practice 04, S 01 (dicembre 2013): S143—S145. http://dx.doi.org/10.4103/0976-3147.116474.

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21

Julsrud, O. J. "VER (VISUAL EVOKED RESPONSE) IN EXAMINATION OF MS PATIENTS". Acta Neurologica Scandinavica 69, S98 (29 gennaio 2009): 376–77. http://dx.doi.org/10.1111/j.1600-0404.1984.tb02526.x.

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22

Kogai, Takayoshi, Atsushi Aoyama, Kaoru Amano e Tsunehiro Takeda. "Visual mismatch response evoked by a perceptually indistinguishable oddball". NeuroReport 22, n. 11 (agosto 2011): 535–38. http://dx.doi.org/10.1097/wnr.0b013e328348ab76.

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23

O'Neill, D., M. Rowan, D. Abraham, J. Feely, J. B. Walsh e D. Ccakley. "The Flash Visual Evoked Response and Alzheimer-Type Dementia". Age and Ageing 19, suppl 2 (1 gennaio 1990): P3. http://dx.doi.org/10.1093/ageing/19.suppl_2.p3-b.

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24

Jones, D. C., e W. T. Blume. "CENTRAL AND PERIPHERAL VISUAL FIELD PATTERN EVOKED RESPONSE LATENCIES". Journal of Clinical Neurophysiology 13, n. 5 (settembre 1996): 449. http://dx.doi.org/10.1097/00004691-199609000-00063.

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25

Katzman, Robert. "THE VALIDITY OF THE VISUAL EVOKED RESPONSE IN MAN". Annals of the New York Academy of Sciences 112, n. 1 (16 dicembre 2006): 238–40. http://dx.doi.org/10.1111/j.1749-6632.1964.tb26753.x.

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26

FAGAN, JOHN E., e ROBERT L. YOLTON. "Theoretical Reliability of Visual Evoked Response-Based Acuity Determinations". Optometry and Vision Science 62, n. 2 (febbraio 1985): 95–99. http://dx.doi.org/10.1097/00006324-198502000-00005.

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27

DOUTHWAITE, WILLIAM ARTHUR, e HEATHER CONNOR. "Mental Concentration and the Pattern Reversal Visual Evoked Response". Optometry and Vision Science 66, n. 1 (gennaio 1989): 61–65. http://dx.doi.org/10.1097/00006324-198901000-00016.

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28

Moore, NC, CA Stewart, KM Estes, NM Khairy, PR Lindsey, RL Vogel e KL Coburn. "Flash-visual-evoked-response delay is associated with aging". European Neuropsychopharmacology 6 (giugno 1996): 250. http://dx.doi.org/10.1016/0924-977x(96)88401-x.

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29

Gupta, N., N. Verma, M. Guidice e K. Kooi. "Visual evoked response in head trauma: pattern-shift stimulus". Neurology 36, n. 4 (1 aprile 1986): 578–81. http://dx.doi.org/10.1212/wnl.36.4.578.

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30

Morrison, J. D., e J. Reilly. "THE PATTERN VISUAL EVOKED CORTICAL RESPONSE IN HUMAN AGEING". Quarterly Journal of Experimental Physiology 74, n. 3 (16 maggio 1989): 311–28. http://dx.doi.org/10.1113/expphysiol.1989.sp003274.

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31

Chen, Shu Li, Zhi Zhong Wang, Li Shi e Xiao Ke Niu. "Analysis of Visual-Evoked Potentials of Primary Visual Cortex under Flash Stimulations". Advanced Materials Research 749 (agosto 2013): 328–32. http://dx.doi.org/10.4028/www.scientific.net/amr.749.328.

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Abstract (sommario):

Visual-evoked potentials (VEPs) which is made up of electrical signals generated by the nervous system in response to a stimulus can be easily recorded from the visual cortex of the experiment animal. There are several types of VEPs, for example, flash evoked potential (FEP), pattern evoked potential [1-3]. The FEP is produced by a visual stimulation with a brief and diffuse flash light. It is frequently used to evaluate the neural activity and sensory processing in the visual system [ and to identify and characterize the changes occurring in the retina and the occipital cortex [4, 5]. VEPs can also provide a further therapeutic approach through the stimulate of monitoring neurophysiologic changes related to diseases [6, 7]. The pattern evoked potentials have been used to assess parametric characteristics of visual perception, detect neuronal irritability and diagnose neurological diseases [8-1.

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32

Herzon, Garrett D., e David L. Zealear. "Intraoperative Monitoring of the Visual Evoked Potential during Endoscopic Sinus Surgery". Otolaryngology–Head and Neck Surgery 111, n. 5 (novembre 1994): 575–79. http://dx.doi.org/10.1177/019459989411100507.

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Iatrogenic blindness resulting from conventional and endoscopic sinus surgery continues to be a major concern to the head and neck surgeon. A new electrophysiologic monitoring technique has been developed that can help avoid damage to the optic nerve and visual system. The approach involves monitoring the visual evoked potential with presentation of flash stimuli to the eyes. Thirty patients with chronic sinusitis underwent endoscopic sinus surgery with visual evoked potential monitoring. The procedures were carried out with patients under intravenous general anesthesia. Needle cortical electrodes were placed in the scalp. A modified light-emitting diode array/goggle was positioned in front of the patient's closed eyes. A triggered flash of 2 Hz was delivered through the goggle to stimulate the patient's retina. Cortical responses were amplified and averaged for 100 trials. Amplitude and peak-latency changes were monitored to alert the surgeon to any change in the visual response during the surgical dissection. Although no changes in response were noted during dissection, cold-water irrigation and reflected telescopic light could produce variations in the recorded responses, as will be discussed. Visual evoked potential monitoring may prevent a surgeon from continuing a bilateral procedure when there is indication of iatrogenic visual loss from dissection on the first side. Visual evoked potential also reassures the operator that no damage has occurred to the visual pathway at the conclusion of a case. Methods, case selection, operative technique, and documentation of monitoring will be discussed.

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33

Ariel, Michael, e Naoki Kogo. "Shunting Inhibition in Accessory Optic System Neurons". Journal of Neurophysiology 93, n. 4 (aprile 2005): 1959–69. http://dx.doi.org/10.1152/jn.00214.2004.

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The interaction of excitatory and inhibitory inputs to the accessory optic system was studied with whole cell recordings in the turtle basal optic nucleus. Previous studies have shown that visual patterns, drifting in the same preferred direction, evoke excitatory and inhibitory postsynaptic events simultaneously. Analysis of the reversal potentials for these events and their pharmacological profile suggest that they are mediated by AMPA and GABAA receptors, respectively. Here, neurons were recorded to study nonlinear interaction between excitatory and inhibitory responses evoked by electrical microstimulation of the retina and pretectum, respectively. The responses to coincident activation of excitatory and inhibitory inputs exhibited membrane shunting in that the excitatory response amplitude, adjusted for changes in driving force, was attenuated during the onset of the inhibitory response. This nonlinear interaction was seen in many but not all stimulus pairings. In some cases, attenuation was followed by an augmentation of the excitatory response. For comparison, the size of the excitatory response was evaluated during a hyperpolarizing current pulse that directly modulated voltage-sensitive channels of a slow rectifying Ih current. Injection of hyperpolarizing current did not cause the attenuation of the excitatory synaptic responses. We conclude that there is a nonlinear interaction between these excitatory and inhibitory synaptic currents that is not due to hyperpolarization itself, but probably is a result of their own synaptic conductance changes, i.e., shunting. Since these events are evoked by identical visual stimuli, this interaction may play a role in visual processing.

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34

Tejada, Pilar Herreros De, Daniel G. Green e Carmen Muñoz Tedó. "Visual thresholds in albino and pigmented rats". Visual Neuroscience 9, n. 3-4 (ottobre 1992): 409–14. http://dx.doi.org/10.1017/s0952523800010816.

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AbstractAlbino rats have recently been reported to have increment thresholds against dim backgrounds that are two log units higher than those of pigmented rats. We, on the other hand, have failed to confirm these differences using electroretinogram b waves and pupillary light reflexes. This paper reports on experiments using evoked potentials from cortex and colliculus and single-unit recordings from colliculus.We recorded visual-evoked potentials from cortex and superior colliculus in the strains of albino (CD) and pigmented (Long-Evans) rats used in the earlier studies. Thresholds were determined on eight fully dark-adapted animals by extrapolating intensity-response curves to the point at which there was zero evoked potential. The average dark-adapted threshold for the visual-evoked cortical potential was —5.26 log cd/m2in pigmented and —5.80 log cd/m2 in albino animals. The average dark-adapted threshold for the superior colliculus evoked response was —5.54 log cd/m2 in pigmented and —5.84 log cd/m2 in albinos. The differences were not statistically significant. On the same apparatus, the average absolute threshold for three human observers was —5.3 log cd/m2, a value close to the rat dark-adapted thresholds. Thus, visual-evoked cortical potentials and superior collicular evoked potentials failed to confirm the report of higher dark-adapted thresholds for albinos. In addition, we find that single units in superior colliculus in the albino rat respond to very dim flashes.

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Makeig, Scott, Marissa Westerfield, Jeanne Townsend, Tzyy-Ping Jung, Eric Courchesne e Terrence J. Sejnowski. "Functionally independent components of early event-related potentials in a visual spatial attention task". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 354, n. 1387 (29 luglio 1999): 1135–44. http://dx.doi.org/10.1098/rstb.1999.0469.

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Spatial visual attention modulates the first negative–going deflection in the human averaged event–related potential (ERP) in response to visual target and non–target stimuli (the N1 complex). Here we demonstrate a decomposition of N1 into functionally independent subcomponents with functionally distinct relations to task and stimulus conditions. ERPs were collected from 20 subjects in response to visual target and non–target stimuli presented at five attended and non–attended screen locations. Independent component analysis, a new method for blind source separation, was trained simultaneously on 500 ms grand average responses from all 25 stimulus–attention conditions and decomposed the non–target N1 complexes into five spatially fixed, temporally independent and physiologically plausible components. Activity of an early, laterally symmetrical component pair (N1a R and N1a L ) was evoked by the left and right visual field stimuli, respectively. Component N1a R peaked ca. 9 ms earlier than N1a L . Central stimuli evoked both components with the same peak latency difference, producing a bilateral scalp distribution. The amplitudes of these components were not reliably augmented by spatial attention. Stimuli in the right visual field evoked activity in a spatio–temporally overlapping bilateral component (N1b) that peaked at ca. 180 ms and was strongly enhanced by attention. Stimuli presented at unattended locations evoked a fourth component (P2a) peaking near 240 ms. A fifth component (P3f) was evoked only by targets presented in either visual field. The distinct response patterns of these components across the array of stimulus and attention conditions suggest that they reflect activity in functionally independent brain systems involved in processing attended and unattended visuospatial events.

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36

Cone-Wesson, Barbara, Richard C. Dowell, Dani Tomlin, Gary Rance e Wu Jia Ming. "The Auditory Steady-State Response: Comparisons with the Auditory Brainstem Response". Journal of the American Academy of Audiology 13, n. 04 (aprile 2002): 173–87. http://dx.doi.org/10.1055/s-0040-1715962.

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Two studies are reported in which the threshold estimates from auditory steady-state response (ASSR) tests are compared to those of click- or toneburst-evoked auditory brainstem responses (ABRs). The first, a retrospective review of 51 cases, demonstrated that both the click-evoked ABR and the ASSR threshold estimates in infants and children could be used to predict the pure-tone threshold. The second, a prospective study of normal-hearing adults, provided evidence that the toneburst-evoked ABR and the modulated tone–evoked ASSR thresholds were similar when both were detected with an automatic detection algorithm and that threshold estimates varied with frequency, stimulus rate, and detection method. The lowest thresholds were obtained with visual detection of the ABA. The studies illustrate that ASSRs can be used to estimate pure-tone threshold in infants and children at risk for hearing loss and also in normal-hearing adults.

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Miyata, Mayumi, Osamu Katsumi, Megumi Oikawa, Junko Ito, Yoshitaka Miyanaga e Jiro Inouye. "Trial of Pattern Reversal Visual Evoked Response in Patients with Visual Conversion Reaction". JAPANESE ORTHOPTIC JOURNAL 36 (2007): 103–11. http://dx.doi.org/10.4263/jorthoptic.36.103.

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38

Ohn, Young-Hoon, Osamu Katsumi, Yoshie Matsui, Hitomi Tetsuka e Tatsuo Hirose. "Snellen Visual Acuity versus Pattern Reversal Visual-Evoked Response Acuity in Clinical Applications". Ophthalmic Research 26, n. 4 (1994): 240–52. http://dx.doi.org/10.1159/000267482.

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39

KORTH, MATTHIAS, RAINER RIX e OTTO SEMBRITZKI. "The sequential processing of visual motion in the human electroretinogram and visual evoked potential". Visual Neuroscience 17, n. 4 (luglio 2000): 631–46. http://dx.doi.org/10.1017/s0952523800174127.

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Abstract (sommario):

Mechanisms of motion vision in the human have been studied extensively by psychophysical methods but less frequently by electrophysiological techniques. It is the purpose of the present investigation to study electrical potentials of the eye (electroretinogram, ERG) and of the brain (visual evoked potential, VEP) in response to moving regular square-wave stripe patterns spanning a wide range of contrasts, spatial frequencies, and speeds. The results show that ERG amplitudes increase linearly with contrast while VEPs, in agreement with the literature, show an amplitude saturation at low contrast. Furthermore, retinal responses oscillate with the fundamental temporal stimulus frequency of the moving pattern while brain responses do not. In both the retina and the brain, the response amplitudes are tuned to certain speeds which is in agreement with the nonlinear correlation-type motion detector. Along the ascending slopes (which means increasing amplitudes) of the tuning functions, the ERG curves overlap at all spatial frequencies if plotted as a function of temporal stimulation frequency. The ascending slopes of the tuning functions of the VEP overlap if plotted as a function of speed. The descending slopes (which means decreasing amplitudes) of the tuning functions show little (ERG) or no (VEP) overlap and the waveforms at high speeds approach pattern-offset-onset responses. These observations suggest that in the retina motion processing along the ascending slopes of the tuning curves takes place by coding the temporal stimulation frequency which depends on the spatial frequency of the moving pattern. In the brain, however, motion processing is by speed independent of spatial frequency. Simple calculations show that the VEP information is decoded from the ERG signal into a speed signal.

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Huang, X., R. D. Mooney e R. W. Rhoades. "Effects of serotonin on retinotectal-, corticotectal-, and glutamate-induced activity in the superior colliculus of the hamster". Journal of Neurophysiology 70, n. 2 (1 agosto 1993): 723–32. http://dx.doi.org/10.1152/jn.1993.70.2.723.

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1. Single-unit recording and iontophoretic techniques were used to test the effects of serotonin (5-HT) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). 2. Iontophoresis of 5-HT produced a visual response suppression of 40% or greater in 78.1% (n = 50) of 64 neurons tested. 5-HT did not augment the visual responses of any of the cells tested. The average response suppression was 75.3 +/- 21.2% (mean +/- S.D.). 3. Iontophoresis of 5-HT had significantly different effects on activation of SC cells by optic chiasm (OX) and visual cortical (CTX) stimulation. Application of 5-HT suppressed the OX-evoked responses of 96.9% (n = 31) of the 32 SC cells tested by at least 40%, and the average response suppression for all 32 neurons tested was 87.1 +/- 22.5%. Application of 5-HT suppressed the responses of only 35.7% (n = 10) of the 28 cells tested with CTX stimulation by at least 40%. The average response suppression for all 28 cells was 35.3 +/- 38.8%. 4. The effects of 5-HT on the glutamate-evoked responses of SC cells that were synaptically "isolated" by concurrent application of Mg2+ were also evaluated. Application of 5-HT produced a response suppression > or = 40% in 29.7% (n = 19) of the 64 neurons tested under these conditions. The average response suppression for all of the cells tested was 28.4 +/- 35.7%. This effect of 5-HT was significantly weaker than that on visually evoked responses of these neurons. 5. The present results demonstrate that 5-HT markedly depresses the visual responses of most superficial layer SC neurons. They suggest further that much of this effect is mediated by presynaptic inhibition of retinotectal transmission.

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ZHANG, YI, RICHARD D. MOONEY e ROBERT W. RHOADES. "Effects of norepinephrine on the activity of visual neurons in the superior colliculus of the hamster". Visual Neuroscience 16, n. 3 (maggio 1999): 541–55. http://dx.doi.org/10.1017/s0952523899163144.

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Abstract (sommario):

Single-unit recording and micropressure ejection techniques were used to test the effects of norepinephrine (NE) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). Application of NE suppressed visually evoked responses by ≥30% in 75% of 40 neurons tested and produced ≥30% augmentation of responses in only 5%. The decrement in response strength was mimicked by application of the α2 adrenoceptor agonist, p-aminoclonidine, the nonspecific β agonist, isoproterenol, and the β1 agonist, dobutamine. These agents had similar effects on responses evoked by electrical stimulation of the optic chiasm and visual cortex. The α1 agonist, methoxamine, augmented the light-evoked responses of 53% of 49 SC cells by ≥30%, but had little effect on responses evoked by electrical stimulation of optic chiasm or visual cortex. The effects of adrenergic agonists upon the glutamate-evoked responses of SC cells that were synaptically “isolated” by concurrent application of Mg2+ were similar to those obtained during visual stimulation. Analysis of effects of NE on visually evoked and background activity indicated that application of this amine did not significantly enhance signal-to-noise ratios for most superficial layer SC neurons, and signal-to-noise ratios were in some cases reduced. These results indicate that NE acts primarily through α2 and β1 receptors to suppress the visual responses of SC neurons. Activation of either of these receptors reduces the responses of SC neurons to either of their two major visual inputs as well as to direct stimulation by glutamate, and it would thus appear that these effects are primarily postsynaptic.

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Khlopkova, Yuliya S., e Ludmila V. Kogoleva. "The study of visual evoked potentials in children with retinopathy of prematurity". Russian Pediatric Ophthalmology 17, n. 3 (28 ottobre 2022): 45–50. http://dx.doi.org/10.17816/rpoj108204.

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Abstract (sommario):

Visual functions in children after retinopathy of prematurity depend not only on the degree of residual clinical changes in the fundus and structural features of the retina, but also on the state of the pathways and higher parts of the visual analyzer, which can be investigated by recording visual evoked potentials. This examination method involves recording the overall response of large populations of cortical neurons to the synchronous flow of impulses coming to them, arising in response to an afferent stimulus and reflecting mainly the electrical activity of the macular area. The registration of visual evoked potentials in the retinopathy of prematurity has an important diagnostic value for identifying the level and degree of damage to the pathways and higher parts of the visual analyzer. This literature review presents the data of foreign and domestic authors on the state of the pathways and higher parts of the visual analyzer in premature babies and children with retinopathy of prematurity using the registration of visual evoked potentials. It has been noted that the magnocellular system, which is activated in response to motor stimuli, is affected to a greater extent in preterm infants than the parvocellular system, which functions in response to pattern stimuli. A comprehensive ophthalmological examination with the registration of visual evoked potentials on the presentation of pattern-reversing stimuli and/or on a flash stimulus should be carried out in children with cicatricial stages of retinopathy of prematurity, in order to identify and confirm the concomitant pathology of the optic nerve. It has been established that the frequency of registration of pathologically altered visual evoked potentials as the severity of retinopathy of prematurity increases, indicating an increase in pathway dysfunction. The effect of laser coagulation of the retina and the volume of its implementation in retinopathy of prematurity on the functional state of the visual analyzer was studied.

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Smith, E. E., M. Vijayappa, F. Lima, P. Delgado, L. Wendell, J. Rosand e S. M. Greenberg. "Impaired visual evoked flow velocity response in cerebral amyloid angiopathy". Neurology 71, n. 18 (27 ottobre 2008): 1424–30. http://dx.doi.org/10.1212/01.wnl.0000327887.64299.a4.

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44

Sittiprapa, Wichian. "Sub-cortical Visual Evoked Response: Problems Solutions and Clinical Applications". Asian Journal of Biological Sciences 5, n. 8 (1 novembre 2012): 449–54. http://dx.doi.org/10.3923/ajbs.2012.449.454.

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FAGAN, JOHN E., FREDERICK G. DOWNARD e ROBERT L. YOLTON. "Steady-State Visual Evoked Response Amplitudes and Concurrent Electroencephalographic Activity". Optometry and Vision Science 62, n. 6 (giugno 1985): 418–22. http://dx.doi.org/10.1097/00006324-198506000-00011.

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Kawashima, Takashi, Satoru Watanabe e Takashi Yamazaki. "Non linearity of the visual evoked response of the cats". Neuroscience Research Supplements 1 (gennaio 1985): S163. http://dx.doi.org/10.1016/s0921-8696(85)80306-6.

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MADDESS, TED, ANDREW CHARLES JAMES e ELIZABETH ANNE BOWMAN. "Contrast response of temporally sparse dichoptic multifocal visual evoked potentials". Visual Neuroscience 22, n. 2 (marzo 2005): 153–62. http://dx.doi.org/10.1017/s0952523805222046.

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Abstract (sommario):

Temporally sparse stimuli have been found to produce larger multifocal visual evoked potentials than rapid contrast-reversal stimuli. We compared the contrast-response functions of conventional contrast-reversing (CR) stimuli and three grades of temporally sparse stimuli, examining both the changes in response amplitude and signal-to-noise ratio (SNR). All stimuli were presented dichoptically to normal adult human subjects. One stimulus variant, the slowest pattern pulse, had interleaved monocular and binocular stimuli. Response amplitudes and SNRs were similar for all stimuli at contrast 0.4 but grew faster with increasing contrast for the sparser stimuli. The best sparse stimulus provided an SNR improvement that corresponded to a recording time improvement of 2.6 times relative to that required for contrast reversing stimuli. Multiple regression of log-transformed response metrics characterized the contrast-response functions by fitting power-law relationships. The exponents for the two sparsest stimuli were significantly larger (P < 0.001) than for the CR stimuli, as were the mean response amplitudes and signal-to-noise ratios for these stimuli. The contrast-dependent response enhancement is discussed with respect to the possible influences of rapid retinal contrast gain control, or intracortical and cortico-geniculate feedback.

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Jones, Keith S., Matthew Middendorf, Grant R. McMillan, Gloria Calhoun e Joel Warm. "Comparing mouse and steady-state visual evoked response-based control". Interacting with Computers 15, n. 4 (agosto 2003): 603–21. http://dx.doi.org/10.1016/s0953-5438(03)00052-3.

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49

Kawashima, Takashi, Satoru Watanabe e Takashi Yamazaki. "Non linearity of the visual evoked response of the cats". Neuroscience Research 3 (gennaio 1985): S163. http://dx.doi.org/10.1016/0168-0102(85)90359-1.

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Collins, Alan D., e Bharat B. Sawhney. "Pseudorandom binary sequence stimulation applied to the visual evoked response". Documenta Ophthalmologica 83, n. 2 (giugno 1993): 163–73. http://dx.doi.org/10.1007/bf01206214.

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