Flicker evoked increase in optic nerve head blood flow in anesthetized cats

Riva, Charles E.; Harino, Seiyo; Shonat, Ross D.; Petrig, Benno L.

doi:10.1016/0304-3940(91)90282-x

Cited by 113 publications

(94 citation statements)

References 11 publications

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“…The maximum CFF value was about 95 Hz and the high-frequency slope was about 1-7 dec per dec. The high-frequency slope in the present study was identical to that reported by Riva et al (1991) although these authors used 30% change in blood flow as a criterion to determine the modulation thresholds. This result is not surprising because, as indicated in Fig.…”

Section: Blood Flow Temporal Contrast Sensitivity Functionsupporting

confidence: 82%

“…Using predominantly diffuse luminance flicker with multiple short flashes to generate functional activity, and laser Doppler flowmetry to monitor the blood flow changes, these studies have convincingly demonstrated that increases in neural activity induce large increases in blood flow in the optic nerve and retinal tissue in cats and human subjects (e.g. Riva, Harino, Shonat & Petrig, 1991;Mendel, Riva, Petrig & Cranstoun, 1994).…”

mentioning

confidence: 99%

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Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Toi

Riva

1995

The Journal of Physiology

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1. The present investigation explored, in thirty‐four anaesthetized cats, the blood flow changes at the optic nerve head elicited by sinusoidally modulated photic stimuli. 2. The stimuli were achromatic, diffuse and had 30 deg diameter field size; the stimulus frequency was varied from 0 to 100 Hz, modulation depth from 0 to 100% and mean retinal illuminance up to 50,000 trolands (td); the blood flow was measured with a near‐infrared (810 nm) laser Doppler flowmeter. 3. At various frequencies, modulation depths and mean retinal illuminance, sinusoidal flicker stimulation always caused an increase in blood flow at the optic nerve head relative to steady stimulation. 4. The frequency response and temporal contrast sensitivity function of the blood flow changes had a bandpass shape; the high‐frequency slope of the frequency response was 3 decades (dec) per decade and that of the temporal contrast sensitivity function was 1.7 dec per dec, close to the slope for cat ‘on’ ganglion cells (2.6 dec per dec). 5. In most cats, the magnitude of the increase in blood flow was a sigmoidal function of modulation depth; in the remainder, the relationship was close to linear. 6. The threshold of blood flow changes varied with respect to mean retinal illuminance similar to Ferry‐Porter's law and the photopic linear slope was 50 Hz dec‐1. 7. In comparison with reported psychophysical and electrophysiological responses elicited by similar stimulations, the results of the present study resemble more those obtained from ganglion cells than those from electroretinograms, visual‐evoked potentials and psychophysics. It is suggested that the blood flow changes at the optic nerve head are induced by the activity of ganglion cells.

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Section: Blood Flow Temporal Contrast Sensitivity Functionsupporting

confidence: 82%

mentioning

confidence: 99%

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Toi

Riva

1995

The Journal of Physiology

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“…Experimental evidence of such coupling in the retina has only been reported recently. For example, flickering light increases blood flow in optic nerve head as detected by LDF (Riva et al, 1991). Physiologic stimuli with oxygen or carbogen modulate tissue oxygenation as measured by oxygen polarographic electrodes (Yu et al, 2000).…”

Section: Imaging Vascular Reactivitymentioning

confidence: 99%

Blood-flow magnetic resonance imaging of the retina

Cheng

Duong

2008

NeuroImage

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This study describes a novel MRI application to image basal blood flow, physiologically induced blood-flow changes, and the effects of isoflurane concentration on blood flow in the retina. Continuous arterial-spin-labeling technique with a separate neck coil for spin labeling was used to image blood flow of the rat retina at 90×90×1500-μm resolution. The average blood flow of the whole retina was 6.3±1.0 ml/g/min under 1% isoflurane, consistent with the high blood flow in the retina reported using other techniques. Blood flow is relatively constant along the length of the retina, except it dipped slightly around the optic nerve head and dropped significantly at the distal edges where the retina terminates. Hyperoxia (100% O 2 ) decreased blood flow 25± 6% relative to baseline (air) due to vasoconstriction. Hypercapnia (5% CO 2 +21% O 2 ) increased blood flow 16±6% due to vasodilation. Increasing isoflurane (a potent vasodilator) concentration to 1.5% increased blood flow to 9.3±2.7 ml/g/min. Blood-flow signals were confirmed to be genuine by repeating measurements after the animals were sacrificed in the MRI scanner. This study demonstrates a proof of concept that quantitative blood flow of the retina can be measured using MRI without depth limitation. Bloodflow MRI has the potential to provide unique insights into retinal physiology, serve as an early biomarker for some retinal diseases, and could complement optically based imaging techniques.

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“…Η αύξηση των μεταβολικών αναγκών οδηγεί σε αύξηση της άρδευσης τόσο στον αμφιβληστροειδή όσο και στη ΚΟΝ [98]. Στην εγκεφαλική και οφθαλμική κυκλοφορία το ΝΟ είναι υπεύθυνο για τη πρόκληση αγγειοδιαστολής.…”

Section: αυτορρύθμισηunclassified

“…Ο αναστολέας του NOS ΝG nitro-L monomethylarginine (L-NMMA) μειώνει σημαντικά τη διάμετρο των αρτηριών (3mg/kg:-2%) και των φλεβών (3mg/kg:-5%) [100]. Πειράματα έδειξαν ότι η αναστολή απελευθέρωσης ΝΟ μετά από ενδοφλέβια χορήγηση L-NMMA επηρέασε την αιματική ροή του χοριοειδούς χιτώνα μειώνοντας την κατά 40% χωρίς να επηρεάσει όμως τη ροή του αίματος στον αμφιβληστροειδή και στη ΚΟΝ [98,101].…”

Section: αυτορρύθμισηunclassified

Μεταβολές Της Μικροκυκλοφορίας Της Κεφαλής Του Οπτικού Νεύρου Κατά Τη Διάρκεια Της Εξωσωματικής Κυκλοφορίας

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Flicker evoked increase in optic nerve head blood flow in anesthetized cats

Cited by 113 publications

References 11 publications

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Blood-flow magnetic resonance imaging of the retina

Μεταβολές Της Μικροκυκλοφορίας Της Κεφαλής Του Οπτικού Νεύρου Κατά Τη Διάρκεια Της Εξωσωματικής Κυκλοφορίας

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