scholarly journals Changes in input strength and number are driven by distinct mechanisms at the retinogeniculate synapse

2014 ◽  
Vol 112 (4) ◽  
pp. 942-950 ◽  
Author(s):  
David J. Lin ◽  
Erin Kang ◽  
Chinfei Chen
Keyword(s):  
Critical Period ◽  
Visual Experience ◽  
Ganglion Cells ◽  
Visual Deprivation ◽  
Homeostatic Plasticity ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Relay Neuron ◽  
Retinogeniculate Synapse ◽  
Dorsal Lateral Geniculate ◽  
Relay Neurons

Recent studies have demonstrated that vision influences the functional remodeling of the mouse retinogeniculate synapse, the connection between retinal ganglion cells and thalamic relay neurons in the dorsal lateral geniculate nucleus (LGN). Initially, each relay neuron receives a large number of weak retinal inputs. Over a 2- to 3-wk developmental window, the majority of these inputs are eliminated, and the remaining inputs are strengthened. This period of refinement is followed by a critical period when visual experience changes the strength and connectivity of the retinogeniculate synapse. Visual deprivation of mice by dark rearing from postnatal day (P)20 results in a dramatic weakening of synaptic strength and recruitment of additional inputs. In the present study we asked whether experience-dependent plasticity at the retinogeniculate synapse represents a homeostatic response to changing visual environment. We found that visual experience starting at P20 following visual deprivation from birth results in weakening of existing retinal inputs onto relay neurons without significant changes in input number, consistent with homeostatic synaptic scaling of retinal inputs. On the other hand, the recruitment of new inputs to the retinogeniculate synapse requires previous visual experience prior to the critical period. Taken together, these findings suggest that diverse forms of homeostatic plasticity drive experience-dependent remodeling at the retinogeniculate synapse.

scholarly journals Prolonged synaptic currents increase relay neuron firing at the developing retinogeniculate synapse

2014 ◽  
Vol 112 (7) ◽  
pp. 1714-1728 ◽  
Author(s):  
Jessica L. Hauser ◽  
Xiaojin Liu ◽  
Elizabeth Y. Litvina ◽  
Chinfei Chen
Keyword(s):  
Time Course ◽  
Ganglion Cells ◽  
Synapse Elimination ◽  
Neuron Firing ◽  
Fluorescence Measurements ◽  
Relay Neuron ◽  
Presynaptic Calcium ◽  
Asynchronous Release ◽  
Retinogeniculate Synapse ◽  
Relay Neurons

The retinogeniculate synapse, the connection between retinal ganglion cells (RGC) and thalamic relay neurons, undergoes robust changes in connectivity over development. This process of synapse elimination and strengthening of remaining inputs is thought to require synapse specificity. Here we show that glutamate spillover and asynchronous release are prominent features of retinogeniculate synaptic transmission during this period. The immature excitatory postsynaptic currents exhibit a slow decay time course that is sensitive to low-affinity glutamate receptor antagonists and extracellular calcium concentrations, consistent with glutamate spillover. Furthermore, we uncover and characterize a novel, purely spillover-mediated AMPA receptor current from immature relay neurons. The isolation of this current strongly supports the presence of spillover between boutons of different RGCs. In addition, fluorescence measurements of presynaptic calcium transients suggest that prolonged residual calcium contributes to both glutamate spillover and asynchronous release. These data indicate that, during development, far more RGCs contribute to relay neuron firing than would be expected based on predictions from anatomy alone.

scholarly journals Neuronal and synaptic plasticity in the visual thalamus in mouse models of glaucoma

2020 ◽  
Author(s):  
Matthew J. Van Hook ◽  
Corrine Monaco ◽  
Jennie C. Smith
Keyword(s):  
Mouse Models ◽  
Ganglion Cells ◽  
Brain Regions ◽  
Synaptic Function ◽  
Homeostatic Plasticity ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Intrinsic Excitability ◽  
Dependent Manner ◽  
Functional Changes ◽  
Genetic Mouse Model

AbstractHomeostatic plasticity plays important roles in regulating synaptic and intrinsic neuronal function to stabilize output following perturbations to circuit activity. In glaucoma, a neurodegenerative disease of the visual system commonly associated with elevated intraocular pressure (IOP), early disease is associated with altered synaptic inputs to retinal ganglion cells (RGCs), changes in RGC intrinsic excitability, and deficits in optic nerve transport and energy metabolism. These early functional changes can precede RGC degeneration and are likely to alter RGC outputs to their target structures in the brain and thereby trigger homeostatic changes in synaptic and neuronal properties in those brain regions. In this study, we sought to determine whether and how neuronal and synaptic function is altered in the dorsal lateral geniculate nucleus (dLGN), an important RGC projection target in the thalamus, and how functional changes relate to IOP. We accomplished this using patch-clamp recordings from thalamocortical (TC) relay neurons in the dLGN in two established mouse models of glaucoma – the DBA/2J (D2) genetic mouse model and an inducible glaucoma model with intracameral microbead injections to elevate IOP. We found that the intrinsic excitability of TC neurons was enhanced in D2 mice and these functional changes were mirrored in recordings of TC neurons from microbead-injected mice. Notably, many neuronal properties were correlated with IOP in older D2 mice, but not younger D2 mice or microbead-injected mice. The frequency of miniature excitatory synaptic currents (mEPSCs) was reduced in both ages of D2 mice, and vGlut2 staining of RGC synaptic terminals was reduced in an IOP-dependent manner in older D2 mice. Among D2 mice, functional changes observed in younger mice without elevated IOP were distinct from those observed in older mice with elevated IOP and RGC degeneration, suggesting that glaucoma-associated changes to neurons in the dLGN might represent a combination of stabilizing/homeostatic plasticity at earlier stages and pathological dysfunction at later stages.

scholarly journals CaV3.2 KO mice have altered retinal waves but normal direction selectivity

2015 ◽  
Vol 32 ◽  
Author(s):  
AARON M. HAMBY ◽  
JULIANA M. ROSA ◽  
CHING-HSIU HSU ◽  
MARLA B. FELLER
Keyword(s):  
Action Potentials ◽  
Ganglion Cells ◽  
Direction Selectivity ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Retinal Waves ◽  
Retinal Projections ◽  
Temporal Properties ◽  
Time Period ◽  
Eye Opening ◽  
Dorsal Lateral Geniculate

AbstractEarly in development, before the onset of vision, the retina establishes direction-selective responses. During this time period, the retina spontaneously generates bursts of action potentials that propagate across its extent. The precise spatial and temporal properties of these “retinal waves” have been implicated in the formation of retinal projections to the brain. However, their role in the development of direction selective circuits within the retina has not yet been determined. We addressed this issue by combining multielectrode array and cell-attached recordings to examine mice that lack the CaV3.2 subunit of T-type Ca2+ channels (CaV3.2 KO) because these mice exhibit disrupted waves during the period that direction selective circuits are established. We found that the spontaneous activity of these mice displays wave-associated bursts of action potentials that are altered from that of control mice: the frequency of these bursts is significantly decreased and the firing rate within each burst is reduced. Moreover, the projection patterns of the retina demonstrate decreased eye-specific segregation in the dorsal lateral geniculate nucleus (dLGN). However, after eye-opening, the direction selective responses of CaV3.2 KO direction selective ganglion cells (DSGCs) are indistinguishable from those of wild-type DSGCs. Our data indicate that although the temporal properties of the action potential bursts associated with retinal waves are important for activity-dependent refining of retinal projections to central targets, they are not critical for establishing direction selectivity in the retina.

Effects of eliminating retinal Y cell input on center-surround interactions in the dorsal lateral geniculate nucleus of the cat

1996 ◽  
Vol 13 (6) ◽  
pp. 1089-1097 ◽  
Author(s):  
Chun Wang ◽  
B. Dreher ◽  
W. Burke
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Ganglion Cells ◽  
Spot Size ◽  
Excitatory Input ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Optimal Size ◽  
Lateral Geniculate ◽  
Optic Fibers ◽  
Dorsal Lateral Geniculate ◽  
Suppression Index

AbstractThe aim of this project was to investigate the interaction between Y retinal ganglion cells and the cells of the dorsal lateral geniculate nucleus (LGNd) of the cat, with particular reference to center-surround antagonism and intrageniculate inhibition. Responses of cells in the LGNd were studied by stimulating the retina with spots of light of constant contrast but varying size. The peak discharges of nonlagged X (XN) cells were strongly suppressed with increase in spot size but the responses of lagged X (XL) cells and nonlagged Y (YN) cells were inhibited much less strongly. The effect of the Y system on these responses was examined by producing a selective block of conduction in Y fibers in one optic nerve by means of a pressure cuff (Y-blocking). These effects were assessed by measuring the peak discharge rates and by calculation of a “peak suppression index.” Y-blocking had no significant effect on the peak suppression index of XL, cells in either lamina or on YN cells in the normal (not Y-blocked) lamina but had significant effects on the responses of XN cells, causing a decrease in peak suppression index, both for cells in laminae receiving their principal excitatory input from the Y-blocked eye (both lamina A and lamina A1 ) as well as those in lamina A (but not lamina A1 ) receiving their excitatory input from the normal eye. These effects were obtained with relatively large spots of light. Thus Y optic fibers have both intralaminar (monocular) and interlaminar (binocular) inhibitory effects on XN cells. In addition to these suppressive effects, the experiments also show that ipsilaterally projecting Y fibers have facilitatory effects on XN cells in lamina A when small spots of light, about optimal size for the XN cell, are used. These results suggest that the Y system plays a powerful role in shaping the responses of XN cells, possibly enhancing visual acuity.

NADPH-diaphorase reactivity in the ventral and dorsal lateral geniculate nuclei of rats

1992 ◽  
Vol 9 (2) ◽  
pp. 211-216 ◽  
Author(s):  
John Mitrofanis
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Total Population ◽  
Ganglion Cells ◽  
Nadph Diaphorase ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Small Cells ◽  
Double Labeling ◽  
Lateral Geniculate ◽  
Cell Class ◽  
Dorsal Lateral Geniculate

AbstractThe present study describes the patterns of NADPH-diaphorase reactivity in the ventral and dorsal lateral geniculate nuclei of rats. In the ventral lateral geniculate nucleus, two distinct populations of NADPH-diaphorase reactive cells are apparent. One population is deeply stained, generally larger in somal size and located in the more superficial or dorsolateral regions of the nucleus. The second population of reactive cells in the nucleus is lightly labeled, small in somal size, and found in deeper or more ventromedial regions of the nucleus. Double labeling with an antibody to GAB A revealed that neither cell class is GABAergic.In the dorsal lateral geniculate nucleus, reactivity is apparent in lightly labeled small cells only, most of which are GABA immunoreactive also. The NADPH-diaphorase reactive cells, however, form only a small proportion of the total population of GABAergic cells in the nucleus. The striking feature of the NADPH-diaphorase reactive cells in the dorsal lateral geniculate nucleus is their spatial distribution. Most cells are located in the more superficial or dorsolateral areas: very few are apparent in deeper or more ventromedial areas of the nucleus. This distribution closely parallels the location of the outer “shell” region of the nucleus (see Reese, 1988), which receives most of its afferents from the smaller class II and III ganglion cells of the retina and from the superior colliculus.

Visual Experience Is Necessary for Maintenance But Not Development of Receptive Fields in Superior Colliculus

2005 ◽  
Vol 94 (3) ◽  
pp. 1962-1970 ◽  
Author(s):  
M. M. Carrasco ◽  
K. A. Razak ◽  
S. L. Pallas
Keyword(s):  
Superior Colliculus ◽  
Critical Period ◽  
Visual Experience ◽  
Sensory Deprivation ◽  
Receptive Fields ◽  
Visual Deprivation ◽  
Visual Development ◽  
Retinotopic Maps ◽  
Nmda Receptor Blockade ◽  
Dark Rearing

Sensory deprivation is thought to have an adverse effect on visual development and to prolong the critical period for plasticity. Once the animal reaches adulthood, however, synaptic connectivity is understood to be largely stable. We reported previously that N-methyl-d-aspartate (NMDA) receptor blockade in the superior colliculus of the Syrian hamster prevents refinement of receptive fields (RFs) in normal or compressed retinotopic projections, resulting in target neurons with enlarged RFs but normal stimulus tuning. Here we asked whether visually driven activity is necessary for refinement or maintenance of retinotopic maps or if spontaneous activity is sufficient. Animals were deprived of light either in adulthood only or from birth until the time of recording. We found that dark rearing from birth to 2 mo of age had no effect on the timing and extent of RF refinement as assessed with single unit extracellular recordings. Visual deprivation in adulthood also had no effect. Continuous dark rearing from birth into adulthood, however, resulted in a progressive loss of refinement, resulting in enlarged, asymmetric receptive fields and altered surround suppression in adulthood. Thus unlike in visual cortex, early visually driven activity is not necessary for refinement of receptive fields during development, but is required to maintain refined visual projections in adulthood. Because the map can refine normally in the dark, these results argue against a deprivation-induced delay in critical period closure, and suggest instead that early visual deprivation leaves target neurons more vulnerable to deprivation that continues after refinement.

Quantitative age-related changes in dorsal lateral geniculate nucleus relay neurons of the rat

2004 ◽  
Vol 48 (4) ◽  
pp. 387-396 ◽  
Author(s):  
Lourdes Vidal ◽  
Concepción Ruı́z ◽  
Alicia Villena ◽  
Florentina Dı́az ◽  
Ignacio Pérez de Vargas
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Lateral Geniculate ◽  
Age Related ◽  
Dorsal Lateral Geniculate ◽  
Age Related Changes ◽  
Relay Neurons
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