Temporal dynamics and magnitude of the blood flow response at the optic disk in normal subjects during functional retinal flicker-stimulation

Schlieren laser Doppler flowmeter for the human optical nerve head with the flicker stimuli

“…The Vel and BF time course increase rapidly to a plateau during flicker illumination and then decrease gradually. This pattern is consistent with the flow measurement of the ONH using other LDF techniques described by Riva et al 18,21 To explain the increase of Vol 18 induced by neurovascular coupling during flicker stimulation, the hypothesis of capillary vasodilatation was the most probable underlying mechanism, especially since some studies suggest that nitric oxide is implicated in the activity-induced BF response. 21 Nevertheless, the intrinsic optical properties of ONH influence the light intensity reflected from the active tissue.…”

“…It is based on a Schlieren optical arrangement which collects only photons that encounter multiple scattering and is collected outside the illumination point. Linearity and sensitivity of the instrument were evaluated using a Doppler simulator and an experiment already published 18 was repeated. With the Doppler simulator, Vel is linearly correlated with the speed of the wheel.…”

Origins of retinal intrinsic signals: A series of experiments on retinas of macaque monkeys

“…68 The blood fl ow increase at the optic nerve head following diffuse luminance fl icker had similar physiological properties to those of magnocellular retinal ganglion cell neural activities. 69,70 On the basis of these data, Riva et al 71 measured the blood fl ow increases following a 15-Hz fl icker stimulus in patients with ocular hypertension and early glaucoma, and found that the fl icker-evoked blood fl ow changes were abnormally reduced. Psychophysical studies using fl ickering stimuli, 72 electrical phosphenes, 73 visually evoked potentials, 74 and electrically evoked pupillary refl exes, 75 which show maximal sensitivities, or responses, at a frequency of 15-20 Hz, have also been reported.…”

“…Riva et al 70,81 showed that the blood fl ow on the optic nerve head in both cats and humans increased following diffuse fl icker stimulation when measured by laser Doppler fl owmetry. Because the stimulus duration used in their studies was as long as 60 s, the precise time course of the signals immediately after the stimulus onset could not be determined.…”

Co-administration effects of α-lipoic acid and nucleo CMP on arousal and sensory cortical activity

“…This effect may be due to dual action of antioxidant and neurotransmission effects that revealed by lipoic acid and nucleo CMP, but nonsignificant effect on CFFF by either nucleo CMP ,lipoic acid or both may be due to small sample size , duration of therapy or drug dosage might be small also, it is nice to mention that few literature reviews mainly about nucleo CMP made us unable to do comparative results, therefore this article may be a base for future central effects of nucleo CMP. Moreover, CFFF results are affected by different factors that surely dissimilar in various experimental studies like frequency and duration of stimulating flicker ,that correlated positively with CFFF so, low frequency around 10 Hz reduce CFFF while higher frequency around 100Hz augment CFFF 27 and most of the previous studies were done on the devices which measure chromatic CFFF ,but in the present study luminated CFFF was measured , since ;chromatic CFFF is lower than luminance CFFF in both patient and normal individual due to differences in temporal informative processing capacity also; luminance CFFF mainly affected by neurodegenerative diseases but, demyelinating disease little affect chromatic CFFF but highly deteriorate with luminance CFFF 28,29,30 this is the most important factor for selection of luminance CFFF in our study. All these factors may explain the variability with other studies.…”