Rod bipolar cells relay visual signals evoked by dim illumination from the outer to inner retina. GABAergic and glycinergic amacrine contact rod cell terminals, where they modulate transmitter release contribute receptive field properties of third order neurones. However, it is not known how these distinct inhibitory inputs affect output subsequent retinal processing. To determine whether GABA(A), GABA(C) glycine receptors made different contributions light-evoked inhibition, we recorded...

Diverse retinal outputs are mediated by ganglion cells that receive excitatory input from distinct classes of bipolar (BCs). These BCs separate visual signals into rod, ON and OFF cone pathways. Although BC signalling is a major determinant the cell-mediated output, it not fully understood how light-evoked, presynaptic inhibition amacrine cell inputs shapes outputs. To determine whether differences in uniquely modulate synaptic output to specific cells, we assessed inhibitory contributions...

While connections between inhibitory interneurons are common circuit elements, it has been difficult to define their signal processing roles because of the inability activate these circuits using natural stimuli. We overcame this limitation by studying amacrine cells in retina. These form spatially extensive networks that shape signaling bipolar cell relay neurons ganglion output neurons. investigated how modulate retinal signals selectively activating with defined light The were assessed...

Synaptic inhibition is determined by the properties of postsynaptic receptors, neurotransmitter release, and clearance, but little known about how these factors shape sensation-evoked inhibition. The retina an ideal system to investigate because it can be activated physiologically with light, separate inhibitory pathways assayed recording from rod bipolar cells that possess distinct glycine, GABA A , C receptors (R). We show receptor differentially spontaneous IPSCs, whereas both transmitter...

Abstract Diabetic retinopathy is now well understood as a neurovascular disease. Significant deficits early in diabetes are found the inner retina that consists of bipolar cells receive inputs from rod and cone photoreceptors, ganglion cells, amacrine modulate these connections. These functional can be measured vivo diabetic humans animal models using electroretinogram (ERG) behavioral visual testing. Early effects on both human model ERGs changes to oscillatory potentials suggest...

Ethanol potentiates glycinergic synaptic transmission to hypoglossal motoneurons (HMs). This effect on changes with postnatal development in that juvenile HMs (P9-13) are more sensitive ethanol than neonate (P1-3). We have now extended our previous study investigate modulation of GABA(A) receptors (GABA(A)Rs), because both GABA and glycine mediate inhibitory brain stem motoneurons. tested the effects GABAergic miniature postsynaptic currents (mIPSCs) recorded from rat an vitro slice...

Emotionally arousing pictures induce increased activation of visual pathways relative to emotionally neutral images. A predominant model for the preferential processing and attention emotional stimuli posits that amygdala modulates sensory through its projections cortices. However, recent behavioral studies have found intact perceptual facilitation in individuals with damage. To determine importance modulations processing, we used functional magnetic resonance imaging examine cortical blood...

Purpose: Recent studies suggest that the neural retinal response to light is compromised in diabetes. Electroretinogram dim rod pathway especially susceptible diabetic damage. The purpose of this study was determine whether diabetes alters signaling. Methods: Diabetes induced C57BL/6J mice by three intraperitoneal injections streptozotocin (STZ; 75 mg/kg), and confirmed blood glucose levels > 200 mg/dL. Six weeks after first injection, whole-cell voltage clamp recordings spontaneous...

Synaptic integration is modulated by inhibition onto the dendrites of postsynaptic cells. However, presynaptic at axonal terminals also plays a critical role in regulation neurotransmission. In contrast to development inhibitory synapses dendrites, GABAergic/glycinergic synaptogenesis axon has not been widely studied. Because retinal bipolar cells receive subclass-specific patterns GABAergic and glycinergic inhibition, they are good model for studying terminals. Here, using whole cell...

During postnatal motoneuron development, the glycine receptor (GlyR) α subunit changes from α2 (fetal) to α1 (adult). To study effect this change has on ethanol potentiation of GlyR currents in hypoglossal motoneurons (HMs), we placed neurons into two groups: neonate [ day 1 3( P1–3)], primarily expressing α2, and juvenile ( P9–13), α1. We found that glycinergic spontaneous miniature inhibitory postsynaptic (mIPSCs) HMs are less sensitive than juveniles. Thirty millimolar increased amplitude...

Previously, we showed that ethanol increases synaptic glycine currents, an effect depends on concentration and developmental age of the preparation. Glycine receptor (GlyR) subunits undergo a shift from alpha2/beta to alpha1/beta neonate juvenile ages, with currents hypoglossal motoneurons (HMs) being less sensitive than those HMs. Here investigate whether these dose effects are also present in excised membrane patches containing GlyRs if changes response kinetics. We outside-out rat HM...

The visual system is highly sensitive to dynamic features in the scene. However, it not known how or where this enhanced sensitivity first occurs. We investigated phenomenon by studying interactions between excitatory and inhibitory synapses second synaptic layer of mouse retina. found that these showed activity-dependent changes signaling stimuli. Excitatory from cone bipolar cells ganglion exhibited strong depression, attributable reduced glutamate release cells. This depression was...

The retina responds to a wide range of light stimuli by adaptation retinal signaling background intensity and the use two different photoreceptors: rods that sense dim cones bright light. Rods signal rod bipolar cells receive significant inhibition from amacrine in dark, especially cell-activated GABAergic cell. This modulates output onto downstream neurons. However, it was not clear how changes when is limited an adapting cone becomes dominant. We found both light-evoked spontaneous cell...

Dopamine modulation of retinal signaling has been shown to be an important part adaptation increased background light levels, but the role dopamine inhibition is not clear. We previously showed that causes a large reduction in rod bipolar cells, potentially match decrease excitation after saturation. In this study, we determined how D1 receptors inner retina contribute modulation. found receptor activation significantly decreased magnitude inhibitory responses from whereas blockade during...

Sensory systems must avoid saturation to encode a wide range of stimulus intensities. One way the retina accomplishes this is by using both dim-light-sensing rod and bright-light-sensing cone photoreceptor circuits. OFF bipolar cells are key point in process, as they receive excitatory input from cones inhibitory AII amacrine via pathway. However, addition cell input, other inputs pathways also modulate light signals. It unknown how these change when switching between or whether all pathway...

During adaptation from dim to bright environments, changes in retinal signaling are mediated, part, by dopamine. Dopamine is released with light and can modulate receptive fields, neuronal coupling, inhibitory receptors, rod pathway inhibition. However, it unclear how dopamine affects inner inhibition cone bipolar cells, which relay visual information photoreceptors ganglion cells important signal processing sites. We tested the hypothesis that (D)1 receptor activation sufficient elicit...

Purpose: The balance of neuronal excitation and inhibition is important for proper retinal signaling. A previous report showed that diabetes selectively reduces light-evoked to the dim light rod pathway, changing this balance. Here, changes in mechanisms inhibitory synaptic transmission after 6 weeks are investigated. Methods: Diabetes was induced C57BL/6J mice by three intraperitoneal injections streptozotocin (STZ, 75 mg/kg), confirmed blood glucose levels more than 200 mg/dL. After weeks,...

The retina adjusts its signaling gain over a wide range of light levels. A functional result this is increased visual acuity at brighter luminance levels (light adaptation) due to shifts in the excitatory center-inhibitory surround receptive field parameters ganglion cells that increases their sensitivity smaller stimuli. Recent work supports idea changes cell spatial with background are part inner retinal mechanisms, possibly including modulation inhibition onto bipolar cells. To determine...

During adaptation to an increase in environmental luminance, retinal signaling adjustments are mediated by the neuromodulator dopamine. Retinal dopamine is released with light and can affect center-surround receptive fields, coupling state between neurons, inhibitory pathways through receptors neurotransmitter release. While field surround of bipolar cells becomes narrower weaker during adaptation, it unknown how affects cell surrounds. If have similar effects, would suggest that could be a...

Neurotransmitter release varies between neurons due to differences in presynaptic mechanisms such as Ca 2+ sensitivity and timing. Retinal rod bipolar cells respond brief dim illumination with prolonged glutamate that is tuned by the differential of GABA glycine from amacrine inner retina. To test if among types are inherent cell properties, we directly activated neurotransmitter electrical stimulation. We found timing electrically evoked inhibitory currents was inherently slow timecourse...