Low-voltage activated calcium currents in ganglion cells of the tiger salamander retina: Experiment and simulation

2007 ◽  
Vol 24 (1) ◽  
pp. 37-51 ◽  
Author(s):  
DORI HENDERSON ◽  
ROBERT F. MILLER
Keyword(s):  
Ganglion Cell ◽  
Cell Function ◽  
Low Voltage ◽  
Ganglion Cells ◽  
Calcium Currents ◽  
Ambystoma Tigrinum ◽  
Tiger Salamander ◽  
Bathing Medium ◽  
Pipette Solution ◽  
Whole Cell Recordings

We examined the functional properties of a low-voltage-activated (LVA) calcium current in ganglion cells of the neotenous tiger salamander (Ambystoma tigrinum) retina. Our analysis was based on whole-cell recordings from acutely dissociated ganglion cell bodies identified by retrograde dye injections. Using a continuously perfused cell preparation, the LVA current was isolated with the use of potassium channel blocking agents added to the bathing medium and the pipette solution, while tetrodotoxin was added to the bathing medium to block Na+channels. Approximately 70% of ganglion cells had an easily identified LVA current. The LVA current activated at membrane potentials more positive than −90 mV, and inactivated rapidly. It was relatively insensitive to nickel (IC50 > 500 μM) and amiloride (IC50 > 750 μM). Voltage- and current-clamp studies allowed us to generate a model of this current using the NEURON simulation program. Studies were also carried out to measure the LVA Ca2+current in ganglion cells with dendrites to confirm that it had a significant dendritic representation. Physiological mechanisms that may depend on LVA Ca2+currents are discussed with an emphasis on the role that dendrites play in ganglion cell function.

Amacrine and ganglion cell contributions to the electroretinogram in amphibian retina

2001 ◽  
Vol 18 (1) ◽  
pp. 147-156 ◽  
Author(s):  
GAUTAM AWATRAMANI ◽  
JUE WANG ◽  
MALCOLM M. SLAUGHTER
Keyword(s):  
Contrast Agents ◽  
Ganglion Cell ◽  
Neuronal Activity ◽  
Opposite Effect ◽  
Cell Function ◽  
Ganglion Cells ◽  
Field Potential ◽  
Tiger Salamander ◽  
Third Order ◽  
Light Responses

The neuronal generators of the b- and d-waves of the electroretinogram (ERG) were investigated in the tiger salamander retina to determine if amacrine and ganglion cells contribute to this field potential. Several agents were used that affect third-order neurons, such as tetrodotoxin, baclofen, and NMDA agonists and antagonists. Baclofen, an agent that enhances light responses in third-order neurons, increased the d-wave and reduced the b-wave. In contrast, agents that decrease light responses in third-order neurons had the opposite effect of enhancing the b-wave and depressing the d-wave. The effect on the d-wave was particularly pronounced. The results indicate that third-order neuronal activity influences b- and d-waves of the ERG. The opposing actions suggest that the b-wave to d-wave ratio might serve as an measure of ganglion cell function.

Evidence for low-voltage-activated (LVA) calcium currents in the dendrites of tiger salamander retinal ganglion cells

2003 ◽  
Vol 20 (2) ◽  
pp. 141-152 ◽  
Author(s):  
DORI HENDERSON ◽  
ROBERT F. MILLER
Keyword(s):  
Current Density ◽  
Low Voltage ◽  
Ganglion Cells ◽  
Calcium Currents ◽  
Tiger Salamander ◽  
Retinal Ganglion ◽  
Cellular Functions ◽  
Impulse Generation ◽  
Dissociated Cells ◽  
Current Densities

We have evaluated the spatial distribution of low-voltage-activated calcium currents in ganglion cells of the tiger salamander retina. Whole-cell recordings were obtained from ganglion cells in a retinal slice preparation and from acutely dissociated ganglion cells that were identified through retrograde dye injection. In single dissociated cells, we estimated the magnitude (pA) and current density (pA/pF) of LVA currents in ganglion cells, both with and without dendritic processes. Ganglion cells that retained a portion of their dendritic arbor had larger LVA calcium currents and higher LVA current densities than those which lacked processes. When cell capacitance measurements were used to derive the surface area of the soma and dendritic processes, we concluded that a higher LVA current density was present in the dendrites; we estimate that, on average, the current density in the dendrites is approximately five times that of the soma. The presence of a significant density of LVA calcium channels in the dendrites of ganglion cells suggests that they could be involved in a number of cellular functions, including dendritic integration of synaptic currents, impulse generation, and homeostatic functions related to changes in the intradendritic calcium concentration.

Estimating the contributions of NMDA and non-NMDA currents to EPSPs in retinal ganglion cells

1997 ◽  
Vol 14 (6) ◽  
pp. 999-1014 ◽  
Author(s):  
T. J. Velte ◽  
W. Yu ◽  
R. F. Miller
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Ambystoma Tigrinum ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
Whole Cell ◽  
Nmda Current ◽  
Control Response ◽  
Whole Cell Recordings

AbstractWhole-cell recordings were obtained from retinal ganglion cells of the tiger salamander (Ambystoma tigrinum) in a superfused slice preparation to evaluate contributions of NMDA (N-methyl-D-aspartate) and KA/AMPA (kainate/α-amino-3-hydroxy-5-methyl-4-isoxalone propionic acid) receptors to excitatory postsynaptic potentials (EPSPs) of retinal ganglion cells. Synaptic activation of retinal ganglion cells was achieved through the use of a brief pressure pulse of hyperosmotic Ringer (Ringer + sucrose) delivered through a microelectrode visually placed in the inner plexiform layer while whole-cell recordings were obtained from adjacent cells in the ganglion cell layer. Separation of NMDA and KA/AMPA excitatory postsynaptic currents (EPSCs) was achieved through the application of the antagonists NBQX and D-AP7, while inhibitory currents were blocked by strychnine and picrotoxin. Simple addition of the two independent EPSCs showed, most often, that the sum of the KA/AMPA and NMDA currents was less than the control response, but in some cases the sum of the two currents exceeded the magnitude of the control response. Neither result was consistent with expectations based on voltage-clamp principles and the assumption that the two currents were independent; for this reason, we considered the possibility of nonlinear interactions between KA/AMPA and NMDA receptors. Computer simulations were carried out to evaluate the summation experiments. We used both an equivalent cylinder model and a more realistic, compartmental model of a ganglion cell constrained by a passive leakage conductance, a linear KA/AMPA synaptic current, and a nonlinear NMDA current based on the well-known, voltage-sensitive Mg2+ block. Computer simulation studies suggest that the hypo- and hyper-summation of NMDA and KA/AMPA currents, observed physiologically, can be accounted for by a failure to adequately space clamp the neuron. Clamp failure leads to enhanced NMDA currents as the ion channels are relieved of the Mg2+ block; their contribution is thus exaggerated depending on the magnitude of the conductance change and the spatial location of the synaptic input.

scholarly journals Synaptic inputs to the ganglion cells in the tiger salamander retina.

1979 ◽  
Vol 73 (3) ◽  
pp. 265-286 ◽  
Author(s):  
D F Wunk ◽  
F S Werblin
Keyword(s):  
Cell Membrane ◽  
Receptive Field ◽  
Ganglion Cell ◽  
Time Course ◽  
Ganglion Cells ◽  
Hybrid Cell ◽  
Amacrine Cells ◽  
Inhibitory Input ◽  
Tiger Salamander ◽  
Synaptic Inputs

The postsynaptic potentials (PSPs) that form the ganglion cell light response were isolated by polarizing the cell membrane with extrinsic currents while stimulating at either the center or surround of the cell's receptive field. The time-course and receptive field properties of the PSPs were correlated with those of the bipolar and amacrine cells. The tiger salamander retina contains four main types of ganglion cell: "on" center, "off" center, "on-off", and a "hybrid" cell that responds transiently to center, but sustainedly, to surround illumination. The results lead to these inferences. The on-ganglion cell receives excitatory synpatic input from the on bipolars and that synapse is "silent" in the dark. The off-ganglion cell receives excitatory synaptic input from the off bipolars with this synapse tonically active in the dark. The on-off and hybrid ganglion cells receive a transient excitatory input with narrow receptive field, not simply correlated with the activity of any presynaptic cell. All cell types receive a broad field transient inhibitory input, which apparently originates in the transient amacrine cells. Thus, most, but not all, ganglion cell responses can be explained in terms of synaptic inputs from bipolar and amacrine cells, integrated at the ganglion cell membrane.

Localization of substance P and GABA in retinotectal ganglion cells of the larval tiger salamander

1994 ◽  
Vol 11 (2) ◽  
pp. 355-362 ◽  
Author(s):  
Carl B. Watt ◽  
Patricia A. Glazebrook ◽  
Valarie J. Florack
Keyword(s):  
Substance P ◽  
Ganglion Cell ◽  
Total Population ◽  
Ganglion Cell Layer ◽  
Ganglion Cells ◽  
Cell Layer ◽  
Tiger Salamander ◽  
Neuronal Populations ◽  
Double Label ◽  
P Cells

AbstractThe present study was performed as part of a systematic examination of the transmitter specificity of neuronal populations in the larval tiger salamander retina. Backfill-labeling of ganglion cells from the optic tectum was combined with double-label immunofluorescence histochemistry to determine if substance P and GABA are localized to ganglion cell populations in the tiger salamander retina. The triple-label analysis revealed the presence of substance P- and GABA-ganglion cells in both central and peripheral regions of the retina. Substance P-immunoreactive ganglion cells comprised 2% of the total population of backfill-labeled ganglion cells, while less than 1% of backfill-labeled ganglion cells expressed GABA immunoreactivity. Ganglion cells were not found to co-label for both substance P and GABA. Backfill-labeled displaced ganglion cells, which comprised 1.4% of the ganglion cell population, were not observed to be immunoreactive for either substance P or GABA. Forty-six point nine percent of substance P-cells in the ganglion cell layer were backfill-labeled and were identified as ganglion cells. GABA ganglion cells comprised less than 1% of GABA-immunoreactive cells in the ganglion cell layer.

scholarly journals Divisive suppression explains high-precision firing and contrast adaptation in retinal ganglion cells

2016 ◽  
Author(s):  
Yuwei Cui ◽  
Yanbin V. Wang ◽  
Silvia J. H. Park ◽  
Jonathan B. Demb ◽  
Daniel A. Butts
Keyword(s):  
Ganglion Cell ◽  
Visual Processing ◽  
Cell Function ◽  
Temporal Dynamics ◽  
Ganglion Cells ◽  
Mouse Retina ◽  
Retinal Ganglion ◽  
Nonlinear Processing ◽  
Generation Mechanisms

Visual processing depends on specific computations implemented by complex neural circuits. Here, we present a circuit-inspired model of retinal ganglion cell computation, targeted to explain their temporal dynamics and adaptation to contrast. To localize the sources of such processing, we used recordings at the levels of synaptic input and spiking output in the in vitro mouse retina. We found that an ON-Alpha ganglion cell's excitatory synaptic inputs were described by a divisive interaction between excitation and delayed suppression, which explained nonlinear processing already present in ganglion cell inputs. Ganglion cell output was further shaped by spike generation mechanisms. The full model accurately predicted spike responses with unprecedented millisecond precision, and accurately described contrast adaption of the spike train. These results demonstrate how circuit and cell-intrinsic mechanisms interact for ganglion cell function and, more generally, illustrate the power of circuit-inspired modeling of sensory processing.

scholarly journals Divisive suppression explains high-precision firing and contrast adaptation in retinal ganglion cells

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Yuwei Cui ◽  
Yanbin V Wang ◽  
Silvia J H Park ◽  
Jonathan B Demb ◽  
Daniel A Butts
Keyword(s):  
Ganglion Cell ◽  
Visual Processing ◽  
Cell Function ◽  
Temporal Dynamics ◽  
Ganglion Cells ◽  
Mouse Retina ◽  
Retinal Ganglion ◽  
Contrast Adaptation ◽  
Generation Mechanisms

Visual processing depends on specific computations implemented by complex neural circuits. Here, we present a circuit-inspired model of retinal ganglion cell computation, targeted to explain their temporal dynamics and adaptation to contrast. To localize the sources of such processing, we used recordings at the levels of synaptic input and spiking output in the in vitro mouse retina. We found that an ON-Alpha ganglion cell's excitatory synaptic inputs were described by a divisive interaction between excitation and delayed suppression, which explained nonlinear processing that was already present in ganglion cell inputs. Ganglion cell output was further shaped by spike generation mechanisms. The full model accurately predicted spike responses with unprecedented millisecond precision, and accurately described contrast adaptation of the spike train. These results demonstrate how circuit and cell-intrinsic mechanisms interact for ganglion cell function and, more generally, illustrate the power of circuit-inspired modeling of sensory processing.

Retinal ganglion cell coding in simulated active vision

2005 ◽  
Vol 22 (6) ◽  
pp. 789-806 ◽  
Author(s):  
FRANKLIN R. AMTHOR ◽  
JOHN S. TOOTLE ◽  
TIMOTHY J. GAWNE
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Retinal Image ◽  
Cell Function ◽  
Ganglion Cells ◽  
Active Vision ◽  
Global Changes ◽  
Retinal Ganglion ◽  
Luminance Change ◽  
Mean Luminance

The image on the retina is almost never static. Eye, head, and body movements, and externally generated motion create rapid and continual changes in the retinal image (“active vision”). Virtually all vision in animals such as primates, which make saccades as often as 3–4 times/s, is based on information that must be derived from the first few hundred milliseconds after sudden, global changes in the retinal image. These changes may be accompanied by large changes in area mean luminance, as well as higher order image contrast statistics. This study investigated how retinal ganglion cell responses, whose response properties have been typically studied and defined in a stable stimulus regime, are affected by sudden changes in mean luminance that are characteristic of active vision. Specifically, the steady-state responses of retinal ganglion cells to static or moving square-wave grating stimuli were recorded in an isolated, superfused rabbit eyecup preparation and compared to responses after saccade-like changes in luminance. The manner of coding after luminance changes was different for different ganglion cell classes; both suppression and enhancement of responses to patterns following luminance changes were found. Brisk-transient Off cells unambiguously signaled the darkening of the overall image, but were also modulated by the subsequently appearing grating stimulus. Several types of On-center cell behavior were observed, ranging from strong suppression of the subsequent response by luminance changes, to strong enhancement. Overall, most ganglion cells distinguished static patterns after a luminance change via differences in their spike discharges nearly as well as before, although there were clear asymmetries between the On and Off pathways. Changes in mean luminance in some ganglion cells, such as On–Off directionally selective ganglion cells, could create large phase shifts in the response to patterned, moving stimuli, although these stimuli were still detected immediately after luminance changes. The results of this study show that the image dynamics of active vision may be a fundamental challenge for the visual system because of strong effects on retinal ganglion cell function. However, rapid extraction of unambiguous information after luminance changes appears to be encoded in differences in the spike discharges in different retinal ganglion cell classes. Asymmetries among ganglion cell classes in sensitivity to luminance changes may provide a basis by which some provide the “context” for interpreting the firing of others.

scholarly journals Clinical electrophysiology of the optic nerve and retinal ganglion cells

Eye ◽  
2021 ◽  
Author(s):  
Oliver R. Marmoy ◽  
Suresh Viswanathan
Keyword(s):  
Optic Nerve ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Retinal Ganglion Cell ◽  
Cell Function ◽  
Ganglion Cells ◽  
Pattern Electroretinogram ◽  
Photopic Negative Response ◽  
Clinical Electrophysiology ◽  
Retinal Ganglion

AbstractClinical electrophysiological assessment of optic nerve and retinal ganglion cell function can be performed using the Pattern Electroretinogram (PERG), Visual Evoked Potential (VEP) and the Photopic Negative Response (PhNR) amongst other more specialised techniques. In this review, we describe these electrophysiological techniques and their application in diseases affecting the optic nerve and retinal ganglion cells with the exception of glaucoma. The disease groups discussed include hereditary, compressive, toxic/nutritional, traumatic, vascular, inflammatory and intracranial causes for optic nerve or retinal ganglion cell dysfunction. The benefits of objective, electrophysiological measurement of the retinal ganglion cells and optic nerve are discussed, as are their applications in clinical diagnosis of disease, determining prognosis, monitoring progression and response to novel therapies.

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