DOI: 10.5061/dryad.47d7wm3tz
title: Cone bipolar cell synapses generate transient versus sustained signals in parallel ON pathways of the mouse retina

description: Parallel processing is a fundamental organizing principle in the nervous
 system and understanding how parallel neural circuits generate distinct
 outputs from common inputs is a key goal of neuroscience. In the mammalian
 retina, divergence of cone signals into multiple feedforward bipolar cell
 pathways forms the initial basis for parallel retinal circuits dedicated
 to specific visual functions. Here, we used patch-clamp electrophysiology,
 electron microscopy and two photon imaging of a fluorescent glutamate
 sensor to examine how kinetically-distinct responses arise in transient
 versus sustained ON alpha RGCs (ON-T and ON-S RGCs) of the mouse retina.
 We directly compared the visual response properties of these RGCs with
 their presynaptic bipolar cell partners, which we identified using 3D
 electron microscopy reconstruction. Different ON bipolar cell subtypes
 (type 5i, type 6 and type 7) had indistinguishable light-driven responses
 whereas extracellular glutamate signals around RGC dendrites and
 postsynaptic excitatory currents measured in ON-T and ON-S RGCs in
 response to the identical stimuli used to probe bipolar cells were
 kinetically distinct. Anatomical examination of the bipolar cell axon
 terminals presynaptic to ON-T and ON-S RGCs suggests that bipolar
 subtype-specific differences in the size of synaptic ribbon-associated
 vesicle pools may contribute to transient versus sustained kinetics. Our
 findings indicate that feedforward bipolar cell synapses are a primary
 point of divergence in kinetically distinct visual pathways.
description: # Cone bipolar cell synapses generate transient versus sustained signals
 in parallel ON pathways of the mouse retina Dataset DOI:
 [10.5061/dryad.47d7wm3tz](https://doi.org/10.5061/dryad.47d7wm3tz) ##
 Description of the data and file structure These files contain source data
 as described in the associated preprint. Details of data collection and
 analysis can be found in the paper. ### Files and variables #### File:
 Figure1_data.mat **Description:** Matlab file containing a single Matlab
 structure with source data for Figures 1D and E. ##### Variables: * Matlab
 structure containing spike triggered averages for On sustained and On
 transient cells (Figure 1D) and collected data on the zero crossing times
 and biphasic indices for the spike triggered averages as plotted in Figure
 1E.  These are indicated by appropriate fields in the Matlab structure.
  For example, ONtransientSTA_Y contains the STA for the On transient
 cells, and STA_timeAx the corresponding time axis. #### File:
 Figure2_data.mat **Description:** Matlab file containing a single Matlab
 structure with source data for Figures 2B-E. ##### Variables * Matlab
 structure containing spike triggered averages (Figure 2B), step responses
 (Figure 2D) and parameters extracted from these and plotted in Figures 2C
 and E.  These are indicated by appropriate fields in the Matlab structure.
 #### **File: Figure3_5_9_EM_data.xlsx** **Description:** Excel spreadsheet
 containing source data for the EM analysis in Figures 3, 5, and 9.  #####
 Variables * Tab 1 (Fig. 3E): Each row shows a count of the number of
 synaptic contacts onto the RGC identified on the first column.  The other
 columns specify the bipolar cell making the contact - with bipolar types
 indicated in the top row. This is the data plotted in Figure 3E. * Tab 2
 (Fig. 5B): Proportion of ribbon inputs to each RGC specified in the first
 two columns that show feedback inhibition.  This is the data plotted in
 Figure 5B.  * Tab 3 (Fig 9B): Ribbon volume (column 2, nm^3) for each of
 the bipolar cells specified in column 1.  This is the data plotted in
 Figure 9B. * Tab 4 (Fig. 9D): Ribbon volume (column 2, nm^3) for each
 synapse made onto the RGCs specified in column 1.  The bipolar type making
 the synapse is identified in column 3.  This is the data plotted in Figure
 9D. * Tab 5 (Fig. 9F): Ribbon volume (column 2, nm^3) and count of nearby
 vesicles for synapses made by the bipolar cell types specified in column
 1.  This is the data plotted in Figure 9F.  #### File: Figure4_data.mat
 **Description:** Matlab file containing a single Matlab structure with
 source data for Figures 4C-F. ##### Variables * Matlab structure
 containing linear filters (Figure 4C), step responses (Figure 4E) and
 parameters extracted from these and plotted in Figures 4D and F.  These
 are indicated by appropriate fields in the Matlab structure. #### File:
 Figure5_data.mat **Description:** Matlab file containing a single Matlab
 structure with source data for Figures 5C-F. ##### Variables * Matlab
 structure containing step responses (Figure 5C and E), and parameters
 extracted from these and plotted in Figures 5D and F.  These are indicated
 by appropriate fields in the Matlab structure. #### File: Figure8_data.mat
 **Description:** Matlab file containing a single Matlab structure with
 source data for Figures 8. ##### Variables * Matlab structure containing
 original traces in Figure 8A and extracted parameters plotted in Figure
 8B. These are indicated by appropriate fields in the Matlab structure.