scholarly journals The functional organization of excitation and inhibition in the dendrites of mouse direction-selective ganglion cells

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Varsha Jain ◽  
Benjamin L Murphy-Baum ◽  
Geoff deRosenroll ◽  
Santhosh Sethuramanujam ◽  
Mike Delsey ◽  
...  
Keyword(s):  
Functional Organization ◽  
Ganglion Cells ◽  
Direction Selectivity ◽  
Neuronal Function ◽  
Dendritic Trees ◽  
Fine Grained ◽  
Two Photon ◽  
Cell Ablation ◽  
Cell Circuit ◽  
Subcellular Level

Recent studies indicate that the precise timing and location of excitation and inhibition (E/I) within active dendritic trees can significantly impact neuronal function. How synaptic inputs are functionally organized at the subcellular level in intact circuits remains unclear. To address this issue, we took advantage of the retinal direction-selective ganglion cell circuit, where directionally tuned inhibition is known to shape non-directional excitatory signals. We combined two-photon calcium imaging with genetic, pharmacological, and single-cell ablation methods to examine the extent to which inhibition ‘vetoes’ excitation at the level of individual dendrites of direction-selective ganglion cells. We demonstrate that inhibition shapes direction selectivity independently within small dendritic segments (<10µm) with remarkable accuracy. The data suggest that the parallel processing schemes proposed for direction encoding could be more fine-grained than previously envisioned.

scholarly journals The functional organization of excitation and inhibition in the dendritic arbors of retinal direction-selective ganglion cells

2019 ◽  
Author(s):  
Varsha Jain ◽  
Benjamin L. Murphy-Baum ◽  
Geoff deRosenroll ◽  
Santhosh Sethuramanujam ◽  
Mike Delsey ◽  
...  
Keyword(s):  
Functional Organization ◽  
Ganglion Cells ◽  
Dendritic Tree ◽  
Amacrine Cells ◽  
Direction Selectivity ◽  
Inhibitory Input ◽  
Processing Scheme ◽  
Fine Grained ◽  
Cell Ablation ◽  
Starburst Amacrine Cells

SUMMARYRecent studies indicate that the precise timing and location of excitation and inhibition (E/I) within active dendritic trees can significantly impact neuronal function. How excitatory and inhibitory inputs are functionally organized at the subcellular level in intact circuits remains unclear. To address this issue, we took advantage of the retinal direction-selective ganglion cell circuit, in which directionally tuned inhibitory GABAergic input arising from starburst amacrine cells shape direction-selective dendritic responses. We combined two-photon Ca2+ imaging with genetic, pharmacological, and single-cell ablation methods to examine local E/I. We demonstrate that when active dendritic conductances are blocked, direction selectivity emerges semi-independently within unusually small dendritic segments (<10 µm). Impressively, the direction encoded by each segment is relatively homogenous throughout the ganglion cell’s dendritic tree. Together the results demonstrate a precise subcellular functional organization of excitatory and inhibitory input, which suggests that the parallel processing scheme proposed for direction encoding could be more fine-grained than previously envisioned.

scholarly journals Retinal waves but not visual experience are required for development of retinal direction selectivity maps

2021 ◽  
Author(s):  
Alexandre Tiriac ◽  
Karina Bistrong ◽  
Marla Feller
Keyword(s):  
Calcium Imaging ◽  
Visual Experience ◽  
Ganglion Cells ◽  
Vertical Component ◽  
Direction Selectivity ◽  
The Body ◽  
Retinal Ganglion ◽  
Retinal Waves ◽  
Two Photon ◽  
Eye Opening

Retinal waves and visual experience have been implicated in the formation of retinotopic and eye-specific maps throughout the visual system, but whether either play a role in the development of the maps within the retina itself is unknown. We explore this question using direction-selective retinal ganglion cells, which are organized into a map that aligns to the body and gravitational axes of optic flow. Using two-photon population calcium imaging, we find that the direction selectivity map is present at eye opening and is unaltered by dark-rearing. Remarkably, the horizontal component of the direction selectivity map is absent in mice lacking normal retinal waves, whereas the vertical component remains normal. These results indicate that intrinsic patterns of activity, rather than extrinsic motion signals are critical for the establishment of direction selectivity maps in the retina.

scholarly journals All-optical interrogation of a direction selective retinal circuit by holographic wave front shaping

2019 ◽  
Author(s):  
G.L.B Spampinato ◽  
E. Ronzitti ◽  
V. Zampini ◽  
U. Ferrari ◽  
F. Trapani ◽  
...  
Keyword(s):  
Bipolar Cell ◽  
Ganglion Cell Layer ◽  
Ganglion Cells ◽  
Single Cells ◽  
Direction Selectivity ◽  
Retinal Neurons ◽  
Two Photon ◽  
Light Levels ◽  
All Optical ◽  
Dim Light

AbstractDirection selective (DS) ganglion cells (GC) in the retina maintain their tuning across a broad range of light levels. Yet very different circuits can shape their responses from bright to dim light, and their respective contributions are difficult to tease apart. In particular, the contribution of the rod bipolar cell (RBC) primary pathway, a key player in dim light, is unclear. To understand its contribution to DSGC response, we designed an all-optical approach allowing precise manipulation of single retinal neurons. Our system activates single cells in the bipolar cell (BC) layer by two-photon (2P) temporally focused holographic illumination, while recording the activity in the ganglion cell layer by 2P Ca2 imaging. By doing so, we demonstrate that RBCs provide an asymmetric input to DSGCs, suggesting they contribute to their direction selectivity. Our results suggest that every circuit providing an input to direction selective cells can generate direction selectivity by itself. This hints at a general principle to achieve robust selectivity in sensory areas.

scholarly journals Synapse-specific direction selectivity in retinal bipolar cell axon terminals

2020 ◽  
Author(s):  
Akihiro Matsumoto ◽  
Weaam Agbariah ◽  
Stella Solveig Nolte ◽  
Rawan Andrawos ◽  
Hadara Levi ◽  
...  
Keyword(s):  
Bipolar Cell ◽  
Ganglion Cells ◽  
Visual Pathway ◽  
Direction Selectivity ◽  
Image Motion ◽  
Gabaergic Inhibition ◽  
Axon Terminals ◽  
Two Photon ◽  
Synaptic Release ◽  
Specific Direction

AbstractThe ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs), due to directionally-tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected, at bipolar cell outputs. Thus, DSGCs receive directionally-aligned glutamatergic inputs from bipolar cell boutons. We further show that this bouton-specific tuning relies on cholinergic excitation and GABAergic inhibition from starburst cells. In this way, starburst cells are able to refine directional tuning in the excitatory visual pathway by modulating the activity of DSGC dendrites and their axonal inputs using two different neurotransmitters.

scholarly journals Brainwide functional networks associated with anatomically- and functionally-defined hippocampal subfields using ultrahigh-resolution fMRI

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei-Tang Chang ◽  
Stephanie K. Langella ◽  
Yichuan Tang ◽  
Sahar Ahmad ◽  
Han Zhang ◽  
...  
Keyword(s):  
Resting State ◽  
Functional Organization ◽  
A Priori ◽  
Longitudinal Axis ◽  
Functional Networks ◽  
Resting State Functional Connectivity ◽  
Underlying Assumption ◽  
Isotropic Resolution ◽  
Hippocampal Subfields ◽  
Fine Grained

AbstractThe hippocampus is critical for learning and memory and may be separated into anatomically-defined hippocampal subfields (aHPSFs). Hippocampal functional networks, particularly during resting state, are generally analyzed using aHPSFs as seed regions, with the underlying assumption that the function within a subfield is homogeneous, yet heterogeneous between subfields. However, several prior studies have observed similar resting-state functional connectivity (FC) profiles between aHPSFs. Alternatively, data-driven approaches investigate hippocampal functional organization without a priori assumptions. However, insufficient spatial resolution may result in a number of caveats concerning the reliability of the results. Hence, we developed a functional Magnetic Resonance Imaging (fMRI) sequence on a 7 T MR scanner achieving 0.94 mm isotropic resolution with a TR of 2 s and brain-wide coverage to (1) investigate the functional organization within hippocampus at rest, and (2) compare the brain-wide FC associated with fine-grained aHPSFs and functionally-defined hippocampal subfields (fHPSFs). This study showed that fHPSFs were arranged along the longitudinal axis that were not comparable to the lamellar structures of aHPSFs. For brain-wide FC, the fHPSFs rather than aHPSFs revealed that a number of fHPSFs connected specifically with some of the functional networks. Different functional networks also showed preferential connections with different portions of hippocampal subfields.

Image Sharpness and Contrast Tuning in the Early Visual Pathway

2017 ◽  
Vol 27 (08) ◽  
pp. 1750045 ◽  
Author(s):  
Eduardo Sánchez ◽  
Rubén Ferreiroa ◽  
Adrián Arias ◽  
Luis M. Martínez
Keyword(s):  
Functional Organization ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Local Contrast ◽  
Retinal Ganglion ◽  
Image Sharpness ◽  
Image Processing Techniques ◽  
Thalamic Relay ◽  
Processing Techniques

The center–surround organization of the receptive fields (RFs) of retinal ganglion cells highlights the presence of local contrast in visual stimuli. As RF of thalamic relay cells follow the same basic functional organization, it is often assumed that they contribute very little to alter the retinal output. However, in many species, thalamic relay cells largely outnumber their retinal inputs, which diverge to contact simultaneously several units at thalamic level. This gain in cell population as well as retinothalamic convergence opens the door to question how information about contrast is transformed at the thalamic stage. Here, we address this question using a realistic dynamic model of the retinothalamic circuit. Our results show that different components of the thalamic RF might implement filters that are analogous to two types of well-known image processing techniques to preserve the quality of a higher resolution version of the image on its way to the primary visual cortex.

scholarly journals GABA release selectively regulates synapse development at distinct inputs on direction-selective retinal ganglion cells

2018 ◽  
Vol 115 (51) ◽  
pp. E12083-E12090 ◽  
Author(s):  
Adam Bleckert ◽  
Chi Zhang ◽  
Maxwell H. Turner ◽  
David Koren ◽  
David M. Berson ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Selective Reduction ◽  
Amacrine Cells ◽  
Gaba Release ◽  
Direction Selectivity ◽  
Inhibitory Synapses ◽  
Retinal Ganglion ◽  
Gabaergic Transmission ◽  
Starburst Amacrine Cells ◽  
Receptor Clusters

Synaptic inhibition controls a neuron’s output via functionally distinct inputs at two subcellular compartments, the cell body and the dendrites. It is unclear whether the assembly of these distinct inhibitory inputs can be regulated independently by neurotransmission. In the mammalian retina, γ-aminobutyric acid (GABA) release from starburst amacrine cells (SACs) onto the dendrites of on–off direction-selective ganglion cells (ooDSGCs) is essential for directionally selective responses. We found that ooDSGCs also receive GABAergic input on their somata from other amacrine cells (ACs), including ACs containing the vasoactive intestinal peptide (VIP). When net GABAergic transmission is reduced, somatic, but not dendritic, GABAA receptor clusters on the ooDSGC increased in number and size. Correlative fluorescence imaging and serial electron microscopy revealed that these enlarged somatic receptor clusters are localized to synapses. By contrast, selectively blocking vesicular GABA release from either SACs or VIP ACs did not alter dendritic or somatic receptor distributions on the ooDSGCs, showing that neither SAC nor VIP AC GABA release alone is required for the development of inhibitory synapses in ooDSGCs. Furthermore, a reduction in net GABAergic transmission, but not a selective reduction from SACs, increased excitatory drive onto ooDSGCs. This increased excitation may drive a homeostatic increase in ooDSGC somatic GABAA receptors. Differential regulation of GABAA receptors on the ooDSGC’s soma and dendrites could facilitate homeostatic control of the ooDSGC’s output while enabling the assembly of the GABAergic connectivity underlying direction selectivity to be indifferent to altered transmission.

Dendritic integration in ganglion cells of the mudpuppy retina

1995 ◽  
Vol 12 (1) ◽  
pp. 165-175 ◽  
Author(s):  
T.J. Velte ◽  
R.F. Miller
Keyword(s):  
Functional Organization ◽  
Simulation Analysis ◽  
Ganglion Cells ◽  
Impedance Matching ◽  
Dendritic Tree ◽  
Membrane Resistance ◽  
Transient Responses ◽  
Dendritic Integration ◽  
Necturus Maculosus ◽  
Integration Efficiency

AbstractComputer simulations were carried out to evaluate the influence of varying the membrane resistance (Rm) on the dendritic integration capacity of three classes of ganglion cells in the mudpuppy (Necturus maculosus) retina. Three broadly different morphological classes of ganglion cells were selected for this study and represent the range of dendritic tree sizes found in the ganglion cell population of this species. Simulations were conducted on anatomical data obtained from cells stained with horseradish peroxidase; each cell was traced, using a computer as an entry device and later converted to a compartmental (electrical) representation of the cell. Computer-simulation analysis used a time-variant conductance change which was similar in waveform to light-activated bipolar cell input. The simulated membrane resistance for each cell varied between 5000 and 100,000 Ω cm2, and conductance changes were introduced into different regions of the soma-dendritic tree to evaluate dendritic integration efficiency. When higher values of Rm are used, even the largest cells become electrotonically compact and attenuation of voltage responses is minimized from distal to soma regions. Responses were less attenuated from proximal to distal regions of the cell because of the favorable impedance matching, and because less current is required to polarize small “sealed” dendritic terminations. Steady-state responses integrate more effectively than transient responses, particularly when Rm is high, since transient responses were more attenuated by the membrane capacitance. The possibility that Rm is a dynamic property of retinal ganglion cells is discussed in view of the functional organization of dendritic integration efficiency as Rm fluctuates from low to high values.

scholarly journals Tonotopic and non-auditory organization of the mouse dorsal inferior colliculus revealed by two-photon imaging

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Aaron Benson Wong ◽  
J Gerard G Borst
Keyword(s):  
Inferior Colliculus ◽  
Spatial Organization ◽  
Functional Organization ◽  
Frequency Tuning ◽  
Gabaergic Neurons ◽  
Two Photon ◽  
Spontaneous Movements ◽  
Multimodal Information ◽  
Auditory Organization

The dorsal (DCIC) and lateral cortices (LCIC) of the inferior colliculus are major targets of the auditory and non-auditory cortical areas, suggesting a role in complex multimodal information processing. However, relatively little is known about their functional organization. We utilized in vivo two-photon Ca2+ imaging in awake mice expressing GCaMP6s in GABAergic or non-GABAergic neurons in the IC to investigate their spatial organization. We found different classes of temporal responses, which we confirmed with simultaneous juxtacellular electrophysiology. Both GABAergic and non-GABAergic neurons showed spatial microheterogeneity in their temporal responses. In contrast, a robust, double rostromedial-caudolateral gradient of frequency tuning was conserved between the two groups, and even among the subclasses. This, together with the existence of a subset of neurons sensitive to spontaneous movements, provides functional evidence for redefining the border between DCIC and LCIC.

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