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Hare, William A.; Ton, Hau

doi:10.1023/a:1020553020264

Cited by 94 publications

(26 citation statements)

References 50 publications

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“…18 These concentrations are within the range of significant suppression of the ganglion cells and the ON and OFF pathways. 11 …”

Section: Methodsmentioning

confidence: 99%

“…In the first experiment, we made intravitreal injections of tetrodotoxin (TTX) to suppress the spiking activity of the innermost retinal layers consisting of ganglion cells, their axons, and spiking amacrine cells. 11 The action of TTX targets voltage-gated sodium channels and thus suppresses the spiking potential of the inner retina while leaving middle and outer retinal cell function intact. 11–13 …”

mentioning

confidence: 99%

“…11 The action of TTX targets voltage-gated sodium channels and thus suppresses the spiking potential of the inner retina while leaving middle and outer retinal cell function intact. 11–13 …”

mentioning

confidence: 99%

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Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins

Schallek

Kardon

Kwon

et al. 2009

Invest. Ophthalmol. Vis. Sci.

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Purpose To elucidate the anatomic origins of stimulus-evoked intrinsic optical signals in the mammalian retina by using selective pharmacologic blockade of specific retinal layers. Methods Four adult cats were used to investigate the stimulus-evoked intrinsic signals. The retinas were visually stimulated with a liquid crystal display (LCD) integrated into a modified fundus camera. The evoked signals in the near infrared (NIR) were recorded with a digital camera to image the changes in the optical reflectance of the retinas. Variants of the electroretinogram (pattern ERG and long-pulse ERG) were also recorded as additional measures of retinal function. Specific retinal layers were inactivated via intravitreal injections of the voltage-gated sodium channel blocker, tetrodotoxin (TTX), the metabotropic glutamate receptor (mGluR6) agonist, 2-amino-4-phosphonobutyric acid (APB), and/or the ionotropic glutamate receptor antagonist cis-2,3 piperidinedicarboxylic acid (PDA). The stimulus-evoked intrinsic signals were imaged before and after drug injection. Results ERG recordings and tests of the consensual pupillary response confirmed the effectiveness of each drug. Yet despite the pharmacologic blockade of the inner retina (TTX) and postreceptoral retinal circuitry (APB and PDA), the stimulus-evoked intrinsic signals remained essentially unaltered from preinjection conditions. Similarly, the time course of the signal did not appreciably shift in time or shape. Conclusions The findings demonstrate that stimulus-evoked intrinsic signals persist after injection of APB, PDA, and TTX, drugs that work to suppress inner and postreceptoral retinal circuitry. The persistence of the intrinsic signals after administration of these drugs indicates that the dominant intrinsic signals are likely to arise from the outer retina.

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“…18 These concentrations are within the range of significant suppression of the ganglion cells and the ON and OFF pathways. 11 …”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins

Schallek

Kardon

Kwon

et al. 2009

Invest. Ophthalmol. Vis. Sci.

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show abstract

“…Final estimated concentrations of 4.8–8.4 µM tetrodotoxin (TTX), 0.83–3.8 mM 2-amino-4-phosphonobutyric acid (APB), and 3.3–3.8 mM cis-2,3-piperidinedicarboxylic acid (PDA) were calculated based on a vitreal volume estimate of 2.1 ml. 11,12 These concentrations are within the range of significant suppression of the ganglion cells and ON and OFF pathways. 12 …”

Section: Methodsmentioning

confidence: 81%

“…11,12 These concentrations are within the range of significant suppression of the ganglion cells and ON and OFF pathways. 12 …”

Section: Methodsmentioning

confidence: 81%

Noninvasive functional imaging of the retina reveals outer retinal and hemodynamic intrinsic optical signal origins

et al. 2009

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We have adapted intrinsic signal optical imaging of neural activity to the noninvasive functional imaging of the retina. Results to date demonstrate the feasibility and potential of this new method of functional assessment of the retina. In response to visual stimuli, we have imaged reflectance changes in the retina that are robust and spatially colocalized to the sites of stimulation. However, the technique is in its infancy and many questions as to the underlying mechanisms remain. In particular, the source and nature of the activity-dependent intrinsic optical signals in the retina need to be characterized and their anatomic origins determined. The studies described here begin to address these issues. The evidence indicates that the imaged signals are driven by the outer retinal layers and have a dominant hemodynamic component.

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Multifocal Electroretinogram and Short-Wavelength Automated PerimetryMeasures in Diabetic Eyes With Little or No Retinopathy

Han¹

2004

Arch Ophthalmol

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To compare severity and locations of abnormalities detected by the multifocal electroretinogram (mfERG) and short-wavelength automated perimetry (SWAP) in diabetic eyes with early or no retinopathy.Methods: One eye from each of 22 patients with diabetes mellitus who had early retinopathy and 18 patients with diabetes mellitus who had no retinopathy were tested on mfERG and SWAP. The mfERG implicit times were interpolated based on SWAP stimulus locations and compared with normative values obtained from 30 age-similar control subjects. The SWAP total threshold deviations were analyzed using an age-based control data set from 255 healthy subjects. The z scores of both measures were derived to allow measurement comparisons.Results: Most responses for the 2 measurements were subnormal in both groups with diabetes mellitus. The 2 measurements showed a similar number of significant abnormalities (z score Ն2), about 40% and 20% of responses for diabetic patients with retinopathy and diabetic patients with no retinopathy, respectively. Local mfERG and SWAP results showed some spatial agreement for subjects with retinopathy (r=-0.38, PϽ.001) but not for those with no retinopathy.Conclusions: Both mfERG and SWAP are sensitive measurements of diabetic dysfunction, even prior to retinopathy. The lack of spatial correspondence between mfERG and SWAP abnormalities in diabetic patients with no retinopathy reflects overlapping, but different, retinal anomalies in early diabetic eye disease.

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Untitled

Cited by 94 publications

References 50 publications

Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins

Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins

Noninvasive functional imaging of the retina reveals outer retinal and hemodynamic intrinsic optical signal origins

Multifocal Electroretinogram and Short-Wavelength Automated PerimetryMeasures in Diabetic Eyes With Little or No Retinopathy

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