Visual dysfunction in retinal and optic nerve disease

Murtha, Timothy; Stasheff, Steven F.

doi:10.1016/s0733-8619(02)00108-1

Cited by 19 publications

(14 citation statements)

References 82 publications

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“…Thus it is likely that the increased level of spontaneous activity that has been described in animals models of RP is also be present in patients with degenerative retinal disease and may participate in the generation of the phantom visual images that are reported by some RP patients [39–41]. These sensations are not continuous, as one might expect they would be if produced by sustained rhythmic spike activity.…”

Section: Discussionmentioning

confidence: 99%

Cellular Origin of Spontaneous Ganglion Cell Spike Activity in Animal Models of Retinitis Pigmentosa

Margolis

Detwiler

2011

Journal of Ophthalmology

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Here we review evidence that loss of photoreceptors due to degenerative retinal disease causes an increase in the rate of spontaneous ganglion spike discharge. Information about persistent spike activity is important since it is expected to add noise to the communication between the eye and the brain and thus impact the design and effective use of retinal prosthetics for restoring visual function in patients blinded by disease. Patch-clamp recordings from identified types of ON and OFF retinal ganglion cells in the adult (36–210 d old) rd1 mouse show that the ongoing oscillatory spike activity in both cell types is driven by strong rhythmic synaptic input from presynaptic neurons that is blocked by CNQX. The recurrent synaptic activity may arise in a negative feedback loop between a bipolar cell and an amacrine cell that exhibits resonant behavior and oscillations in membrane potential when the normal balance between excitation and inhibition is disrupted by the absence of photoreceptor input.

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Section: Discussionmentioning

confidence: 99%

Cellular Origin of Spontaneous Ganglion Cell Spike Activity in Animal Models of Retinitis Pigmentosa

Margolis

Detwiler

2011

Journal of Ophthalmology

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“…Thus, it is possible that the persistent retinal activity we have observed in the blind retina is the source of photopsia in patients with retinitis pigmentosa who describe the sensation of seeing random flashes or shimmering lights in the absence of visual stimulation (Lepore, 1990;Amos, 1999;Murtha and Stasheff, 2003).…”

mentioning

confidence: 99%

Functional Stability of Retinal Ganglion Cells after Degeneration-Induced Changes in Synaptic Input

Margolis¹,

Newkirk²,

Euler³

et al. 2008

Journal of Neuroscience

197

262

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Glutamate released from photoreceptors controls the activity and output of parallel pathways in the retina. When photoreceptors die because of degenerative diseases, surviving retinal networks are left without their major source of input, but little is known about how photoreceptor loss affects ongoing synaptic activity and retinal output. Here, we use patch-clamp recording and two-photon microscopy to investigate morphological and physiological properties of identified types of ON and OFF retinal ganglion cells (RGCs) in the adult (36 -210 d old) retinal degeneration rd-1/rd-1 mouse. We find that strong rhythmic synaptic input drives ongoing oscillatory spike activity in both ON and OFF RGCs at a fundamental "beating" frequency of ϳ10 Hz. Despite this aberrant activity, ON and OFF cells maintain their characteristic dendritic stratification, intrinsic firing properties, including rebound firing in OFF cells, balance of synaptic excitation and inhibition, and dendritic calcium signaling. Thus, RGCs are inherently stable during degeneration-induced retinal activity.

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“…28 Unfortunately, pupil and contrast sensitivity data could not be used due to inconsistent testing conditions. Were this not the case, physiologic assessment would have been enhanced.…”

Section: Discussionmentioning

confidence: 99%