Visual Evoked Potentials in the Clinically Normal Dog

Strain, George M.; Jackson, Rose M.; Tedford, Bruce L.

doi:10.1111/j.1939-1676.1990.tb00901.x

Cited by 20 publications

(24 citation statements)

References 18 publications

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“…On the other hand, the flash VEP recorded between the forehead and the inion consisted of 3 positive and 2 negative components like as those reported previously [10].…”

Section: Discussionmentioning

confidence: 68%

“…The flash VEP: The flash VEP was recorded using needle electrodes inserted in the midline of the scalp according to the method reported by Strain et al [10]. The electrodes of recording, reference, and ground were placed over the midline of the nuchal crest (Oz), forehead (Fpz) and vertex, respectively ( Fig.…”

Section: Animalsmentioning

confidence: 99%

“…The flash VEP stimulated by the flashlight has also been recorded in dogs [1,5,6,[9][10][11], however the generators of potentials in amplitude and/or latency of the waves, are not well known. Recently, topographic analysis of evoked potentials have been applied in human using multiple electrodes on the scalp for elucidating generators of the waves in the flash VEP [3,7,8,12].…”

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confidence: 99%

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Topographic Analysis of Flash Visual Evoked Potentials in Dogs

Kimotsuki

Yasuda

Tamahara

et al. 2005

The Journal of Veterinary Medical Science

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ABSTRACT. Visual evoked potentials by flash stimulation (flash VEP) were analyzed in dogs using a topographic method. The flash VEP consisted of 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) components by 150 msec after the flash stimuli. On the topographic mappings, a negative response area was observed in the frontal region of the scalp in the stimulated site followed by the shifting of the area to the contralateral frontal region and occipital region, during the first 100 msec. The negative response area in the frontal region in the stimulated site, contralateral frontal and temporal region, and occipital region were corresponded to N1, P2, and N2 on the flash VEP, respectively, according to their latencies. In the dogs with experimentally impaired the right lateral geniculate body, the latency of P2 was prolonged, and N2 and P3 were disappeared after the left eye stimulation. On the topographic mapping, only the early negative response area was detected on the stimulated site of the frontal region of the brain. Therefore, it is concluded that P1 and N1, P2, and N2 are referred to the retinal potentials, the potentials from the retina to the brainstem included the lateral geniculate body, and those from the brainstem to the visual cortex, respectively. KEY WORDS: canine, flash stimulus, lateral geniculate body, topographic mapping, visual evoked potential.

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“…On the other hand, the flash VEP recorded between the forehead and the inion consisted of 3 positive and 2 negative components like as those reported previously [10].…”

Section: Discussionmentioning

confidence: 68%

Section: Animalsmentioning

confidence: 99%

mentioning

confidence: 99%

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Topographic Analysis of Flash Visual Evoked Potentials in Dogs

Kimotsuki

Yasuda

Tamahara

et al. 2005

The Journal of Veterinary Medical Science

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“…In this study, the latency of P2 and the later peaks were significantly delayed, and the amplitudes of N2-P2 and P2-N3 were decreased with age advanced. The flash VEP was demonstrated to be a specific indicator of dementia in human, particularly on the latency of P2 [4,18,22], since no P2 latency delayed was detected in the patient with depres- …”

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confidence: 99%

“…Sci. 68(1): 79-82, 2006 Visual evoked potentials (VEPs) indicated electrophysiological responses from retina to visual cortex is reported to be an useful technique for evaluating optic pathway [8] and also to be a sensitive indicator for dementia in human [4,18,22]. Visser et al [21] demonstrated that the latency of the flash VEP components was delayed in the patients with dementia, especially Alzheimer's disease.…”

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confidence: 99%

Age-Associated Changes of Flash Visual Evoked Potentials in Dogs

Kimotsuki¹,

Yasuda

Tamahara

et al. 2006

The Journal of Veterinary Medical Science

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ABSTRACT. Age-associated changes of visual evoked potentials by flash stimulation (flash VEP) were evaluated in 53 beagle dogs aged from 1-to 15-year-old. Among the components of flash VEP consisted of 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) peaks by 150 msec, the latency of P2 and the later peaks (N2 and P3) were significantly delayed with aging. Both amplitudes of the P2-N2 and N2-P3 also showed a significant correlation with aging. The flash VEP is considered to be an available and useful technique to evaluate not only for visual pathway, but also some disturbance of neurological functions, like as those reported in demented human. KEY WORDS: age-associated change, canine, flash VEP.J. Vet. Med. Sci. 68(1): 79-82, 2006 Visual evoked potentials (VEPs) indicated electrophysiological responses from retina to visual cortex is reported to be an useful technique for evaluating optic pathway [8] and also to be a sensitive indicator for dementia in human [4,18,22]. Visser et al. [21] demonstrated that the latency of the flash VEP components was delayed in the patients with dementia, especially Alzheimer's disease. The latency of the positive peak 2 (P2 :mean latency was 100 msec) and the later components were significantly delayed, although the similar results were sometimes detected in aged human. The flash VEP recorded in dogs showed 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) components by 150 msec after the flash stimuli, like as those reported in human [11,17,19]. In addition, various age-associated pathological and/or physiological changes were commonly observed in aged dogs as well as aged human [5,10]. Since there are few diagnostic techniques for dementia in dogs, age-associated changes of the flash VEP were evaluated using various aged beagle dogs.Total 53 beagle dogs (25 male and 28 female) aged from 1-to 15-year-old kept in Medical Safety Research Laboratories, Sankyo Co., Ltd., were used.The flash VEP was recorded using needle electrodes inserted in the midline of the scalp according to the method reported by Strain et al. [18]. Briefly, electrodes of recording, reference, and ground were placed over the midline of the nuchal crest, forehead, and vertex, respectively. Prior to recording, the dogs were instilled the mydriatic drug, including tropicamide and phenylephrine hydrochloride, and subcutaneously given atropine sulfate (0.05 mg/kg) and intramuscularly given xylazine (2-3 mg/kg) for the sedation. Then the dogs were dark-adapted at least 1 hr and the flash VEP were recorded in the dark shielded room. The white flash stimulus was given 1/sec with the intensity of 0.6 joule using a photostimulator (SLS-3100 Photostimulator, Nihon Kohden Co., Tokyo, Japan). The xenon lamp was located about 15 cm in front of the examined eye and another eye was covered with the black cloth. The responses were recorded with signal averager (Neuropack Four Mini, Nihon Kohden Co, Tokyo, Japan). The bandpass filter was set at 1 Hz low and 1,000 Hz high. In this study, consecutive 30 responses wer...

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