scholarly journals Two-stage adaptation of inhibition mediates predictive sensitization in the retina

2017 ◽  
Author(s):  
David B. Kastner ◽  
Yusuf Ozuysal ◽  
Georgia Panagiotakos ◽  
Stephen A. Baccus
Keyword(s):  
Ganglion Cells ◽  
Amacrine Cells ◽  
General Mechanism ◽  
Short Term ◽  
Critical Function ◽  
Short Term Plasticity ◽  
Multiple Species ◽  
The Right ◽  
Multielectrode Recording ◽  
Local Stimulation

AbstractA critical function of the nervous system is the prediction of future sensory input. One such predictive computation is retinal sensitization, a form of short-term plasticity seen in multiple species that elevates local sensitivity following strong local stimulation. Here we perform a causal circuit analysis of retinal sensitization using simultaneous intracellular and multielectrode recording in the salamander. We show, using direct current injection into inhibitory sustained amacrine cells that a decrease in amacrine transmission is necessary, sufficient and occurs at the right time and manner to cause sensitization in ganglion cells. Because of neural dynamics and nonlinear pathways, a computational model is essential to explain how a change in steady inhibitory transmission causes sensitization. Whereas adaptation of excitation removes an expected result in order to transmit novelty, adaptation of inhibition provides a general mechanism to enhance the sensitivity to the sensory feature conveyed by an inhibitory pathway, creating a prediction of future input.

scholarly journals Optical Coherence Tomography Findings in Unilateral Peripheral Cone Dysfunction Syndrome: A Case Report

2019 ◽  
Author(s):  
Tetsuya Hasegawa ◽  
Soichi Tetsuka ◽  
Aya Yamaguchi ◽  
Chieko Kobashi ◽  
Tomomi Sato ◽  
...  
Keyword(s):  
Visual Field ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Photoreceptor Cells ◽  
Field Testing ◽  
Horizontal Cells ◽  
Cone Photoreceptor ◽  
Visual Field Testing ◽  
Cone Dysfunction ◽  
The Right

Abstract Introduction: To report a case of unilateral peripheral cone dysfunction syndrome and evaluate the associated clinicopathological changes using swept-source optical coherence tomography (SS-OCT). Case Presentation: A 39-year-old Japanese woman reported a visual field defect of 2-years duration in the right eye. The patient underwent visual field testing, full-field electroretinography (ff-ERG), SS-OCT, and a routine ophthalmologic examination. The best-corrected visual acuity was 20/20 bilaterally. The funduscopy examination was normal bilaterally. Visual field testing showed a relative paracentral scotoma in the right eye. SS-OCT scans showed an unclear interdigitation zone (IZ) throughout the posterior pole except for the foveal zone in the right eye. SS-OCT macular analysis showed thinning of the ganglion cell layer (GCL) and inner plexiform layer (IPL) corresponding to the region of the IZ defect. ff-ERG showed almost normal flash ERGs and normal rod responses bilaterally. The cone response and flicker ERG response were decreased markedly only in the right eye. Conclusion: To the best of our knowledge, this is the first case report of unilateral peripheral cone dysfunction syndrome in which SS-OCT showed pathological changes in the GCL and IPL. The OCT findings corresponded well to the ERG changes and visual field abnormality. Because foveolar cone photoreceptor cells are connected in a one-to-one correspondence to retinal ganglion cells without connection to the horizontal cells or amacrine cells, the GCL and IPL were not present in the fovea. Based on this analysis, we speculated that the primary lesion of peripheral cone dysfunction syndrome is not in the cone photoreceptor cells but in the horizontal cells and/or amacrine cells. The clinicopathological changes in the ganglion cells and cone photoreceptor cells might be the subsequent pathologies in the horizontal cells in peripheral cone dysfunction syndrome.

Retinal ganglion cell death induced by unilateral tectal ablation in Xenopus

1989 ◽  
Vol 2 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Charles Straznicky ◽  
Roger McCart ◽  
Pál Tóth
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Surgical Removal ◽  
Retinal Ganglion ◽  
Retrograde Degeneration ◽  
Optic Axons ◽  
Optic Fibers ◽  
The Right

AbstractThe survival of retinal ganglion cells (GCs) in the left eye was studied on retinal wholemounts from 2–33 weeks after the surgical removal of the right tectum in juvenile Xenopus. Two to five weeks after tectal removal, about 76% of neurons of the retinal ganglion cell (GC) layer showed signs of retrograde degeneration: swelling of their somata and chromatolysis. Neurons that were not affected by the operation were taken to be either displaced amacrine cells (DAs) or GCs not projecting to the tectum. A portion of GCs showing retrograde degeneration became pyknotic and died within the period of 2–16 weeks after operation. Counts of surviving GCs 20–33 weeks after tectal removal amounted to about 55% of the corresponding neuron number in the right intact retina of the same animal. No discernible GC loss was observed in animals where only the optic fibers were cut at their entry point to the tectum indicating that axotomy alone, followed by rapid regrowth to the target, does not adversely influence the survival of GCs. In long-surviving animals, the left optic nerve was exposed to cobaltic-lysine complex and the position of filled optic axons within the brain determined. Optic axons whose tectal target had been removed were seen to cross over to the left intact tectum via the posterior and pretectal commissures. Aberrant projections were detected to the ipsilateral tectum and the diencephalic periventricular grey in addition to an increased projection to the accessory optic nucleus. It is concluded that the removal of the tectum, the main target of optic fiber projection, induces a very substantial GC death. Since only a portion of optic fibers were able to grow to alternative targets, the surviving GCs may have also included those with main projection areas to the diencephalic visual centers.

scholarly journals Retinohypothalamic Tract Synapses in the Rat Suprachiasmatic Nucleus Demonstrate Short-Term Synaptic Plasticity

2010 ◽  
Vol 103 (5) ◽  
pp. 2390-2399 ◽  
Author(s):  
Mykhaylo G. Moldavan ◽  
Charles N. Allen
Keyword(s):  
Synaptic Transmission ◽  
Suprachiasmatic Nucleus ◽  
Ganglion Cells ◽  
Brain Slices ◽  
Release Mechanism ◽  
Dependent Manner ◽  
Short Term ◽  
Frequency Dependent ◽  
Short Term Plasticity ◽  
Retinohypothalamic Tract

The master circadian pacemaker located in the suprachiasmatic nucleus (SCN) is entrained by light intensity–dependent signals transmitted via the retinohypothalamic tract (RHT). Short-term plasticity at glutamatergic RHT–SCN synapses was studied using stimulus frequencies that simulated the firing of light sensitive retinal ganglion cells. The evoked excitatory postsynaptic current (eEPSC) was recorded from SCN neurons located in hypothalamic brain slices. The eEPSC amplitude was stable during 0.08 Hz stimulation and exhibited frequency-dependent short-term synaptic depression (SD) during 0.5 to 100 Hz stimulus trains in 95 of 99 (96%) recorded neurons. During SD the steady-state eEPSC amplitude decreased, whereas the cumulative charge transfer increased in a frequency-dependent manner and saturated at 20 Hz. SD was similar during subjective day and night and decreased with increasing temperature. Paired-pulse stimulation (PPS) and voltage-dependent Ca2+ channel (VDCC) blockers were used to characterize a presynaptic release mechanism. Facilitation was present in 30% and depression in 70% of studied neurons during PPS. Synaptic transmission was reduced by blocking both N- and P/Q-type presynaptic VDCCs, but only the N-type channel blocker significantly relieved SD. Aniracetam inhibited AMPA receptor desensitization but did not alter SD. Thus we concluded that SD is the principal form of short-term plasticity at RHT synapses, which presynaptically and frequency-dependently attenuates light-induced glutamatergic RHT synaptic transmission protecting SCN neurons against excessive excitation.

scholarly journals Optical Coherence Tomography Findings in Unilateral Peripheral Cone Dysfunction Syndrome: A Case Report

2019 ◽  
Author(s):  
Tetsuya Hasegawa ◽  
Soichi Tetsuka ◽  
Aya Yamaguchi ◽  
Chieko Kobashi ◽  
Tomomi Sato ◽  
...  
Keyword(s):  
Visual Field ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Photoreceptor Cells ◽  
Field Testing ◽  
Horizontal Cells ◽  
Cone Photoreceptor ◽  
Visual Field Testing ◽  
Cone Dysfunction ◽  
The Right

Abstract Introduction: To report a case of unilateral peripheral cone dysfunction syndrome and evaluate the associated clinicopathological changes using swept-source optical coherence tomography (SS-OCT). Case Presentation: A 39-year-old Japanese woman reported a visual field defect of 2-years duration in the right eye. The patient underwent visual field testing, full-field electroretinography (ff-ERG), SS-OCT, and a routine ophthalmologic examination. The best-corrected visual acuity was 20/20 bilaterally. The funduscopy examination was normal bilaterally. Visual field testing showed a relative paracentral scotoma in the right eye. SS-OCT scans showed an unclear interdigitation zone (IZ) throughout the posterior pole except for the foveal zone in the right eye. SS-OCT macular analysis showed thinning of the ganglion cell layer (GCL) and inner plexiform layer (IPL) corresponding to the region of the IZ defect. ff-ERG showed almost normal flash ERGs and normal rod responses bilaterally. The cone response and flicker ERG response were decreased markedly only in the right eye. Conclusion: To the best of our knowledge, this is the first case report of unilateral peripheral cone dysfunction syndrome in which SS-OCT showed pathological changes in the GCL and IPL. The OCT findings corresponded well to the ERG changes and visual field abnormality. Because foveolar cone photoreceptor cells are connected in a one-to-one correspondence to retinal ganglion cells without connection to the horizontal cells or amacrine cells, the GCL and IPL were not present in the fovea. Based on this analysis, we speculated that the primary lesion of peripheral cone dysfunction syndrome is not in the cone photoreceptor cells but in the horizontal cells and/or amacrine cells. The clinicopathological changes in the ganglion cells and cone photoreceptor cells might be the subsequent pathologies in the horizontal cells in peripheral cone dysfunction syndrome.

scholarly journals Preserving inhibition with a disinhibitory microcircuit in the retina

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Qiang Chen ◽  
Robert G Smith ◽  
Xiaolin Huang ◽  
Wei Wei
Keyword(s):  
Synaptic Plasticity ◽  
Mutual Influence ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Direction Selectivity ◽  
Short Term ◽  
Brain Circuits ◽  
Mammalian Retina ◽  
Starburst Amacrine Cells ◽  
Noise Resilience

Previously, we found that in the mammalian retina, inhibitory inputs onto starburst amacrine cells (SACs) are required for robust direction selectivity of On-Off direction-selective ganglion cells (On-Off DSGCs) against noisy backgrounds (Chen et al., 2016). However, the source of the inhibitory inputs to SACs and how this inhibition confers noise resilience of DSGCs are unknown. Here, we show that when visual noise is present in the background, the motion-evoked inhibition to an On-Off DSGC is preserved by a disinhibitory motif consisting of a serially connected network of neighboring SACs presynaptic to the DSGC. This preservation of inhibition by a disinhibitory motif arises from the interaction between visually evoked network dynamics and short-term synaptic plasticity at the SAC-DSGC synapse. Although the disinhibitory microcircuit is well studied for its disinhibitory function in brain circuits, our results highlight the algorithmic flexibility of this motif beyond disinhibition due to the mutual influence between network and synaptic plasticity mechanisms.

Objective Measurement of Sustained Pupillary Constriction: A Pilot Study Using an App-Based Pupilometer

2020 ◽  
pp. 57-63
Keyword(s):  
Ganglion Cells ◽  
Modern Technology ◽  
Objective Measurement ◽  
Retinal Ganglion ◽  
Case Examples ◽  
Pupillary Reaction ◽  
Sympathetic Nervous Systems ◽  
Pupillary Constriction ◽  
The Individual ◽  
The Right

Background: The pupillary reaction is controlled by the two main branches of the autonomic nervous system, namely the parasympathetic and sympathetic nervous systems. New discoveries in pupil research has identified that intrinsically photosensitive retinal ganglion cells have an impact on pupillary constriction, particularly sustained pupillary constriction. In the current paper, an objective measurement of sustained pupillary constriction versus the inability to maintain sustained pupillary constriction are observed. The variability in the sustained pupillary constriction, i.e. Alpha Omega pupil, can be objectively identified with the use of modern technology. Case Examples: Two female subjects were adapted to dim illumination, and then two objective pupil measurements of the right eye using Reflex – PLR Analyzer by BrightLamp© (Indianapolis, IN, USA) with sustained illumination were obtained. Subject 1, a 25 year-old-female, demonstrated normal ability of the pupil to constrict and sustain constriction for 10 seconds. She was used as a control for subject 2. Subject 2, a 27 year-old-female, demonstrated the inability to sustain pupillary constriction. She reported being under great psychological stress. Her pupil began to re-dilate between 2 and 3 seconds after the initial constriction. Conclusion: Objective pupillometry can be used to assist in many diagnoses and provides the clinician invaluable information on the state of the individual, and qualifications of sustained pupillary constriction can now be assessed in an objective manner.

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