Download Shared and distinct retinal input to the mouse superior colliculus and

J Neurophysiol 116: 602– 610, 2016.
First published May 11, 2016; doi:10.1152/jn.00227.2016.
Rapid Report
Shared and distinct retinal input to the mouse superior colliculus and dorsal
lateral geniculate nucleus
Erika M. Ellis,1 Gregory Gauvain,1 Benjamin Sivyer,1,2 and Gabe J. Murphy1
1
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia; and 2Queensland Brain Institute, The
University of Queensland, St Lucia, Queensland, Australia
Submitted 16 March 2016; accepted in final form 10 May 2016
retina; retinorecipient; superior colliculus; thalamus
NEW & NOTEWORTHY
Our results suggest that the mouse superior colliculus (SC)
has access to input from most of the retinal ganglion cells
(RGCs) that innervate the dorsal lateral geniculate nucleus
(dLGN). By comparison, a number of RGC types appear to
innervate the SC but not the dLGN; these RGCs generally
exhibit more transient responses and respond best to small
stimuli.
represent information about
overlapping but distinguishable features of visual stimuli. Neurons in the dorsal stream of the primate visual system, for
example, frequently encode information about object motion,
whereas neurons in the ventral stream often encode information about chromatic and/or spatial characteristics (Livingstone
and Hubel 1988; Maunsell and Newsome 1987; see, however,
Merigan and Maunsell 1993). Neurons in distinct areas of the
DIFFERENT REGIONS OF THE BRAIN
Address for reprint requests and other correspondence: G. J. Murphy, Allen
Institute for Brain Science, 615 Westlake Ave. N., Seattle, WA 98109 (e-mail:
[email protected]).
602
rodent visual system exhibit similar functional differences
(Andermann et al. 2011; Garrett et al. 2014; Marshel et al.
2011).
Parallel processing is not restricted to visual cortical areas.
Indeed, although some neurons in the mouse dorsal lateral
geniculate nucleus (dLGN) and superior colliculus (SC) encode information about the same features of visual stimuli, e.g.,
orientation or motion direction (Ahmadlou and Heimel 2015;
Feinberg and Meister 2015; Marshel et al. 2012; Zhao et al.
2013), most dLGN and SC neurons respond best to distinct
characteristics of visual stimuli. The overwhelming majority of
dLGN neurons in rodents, as in primates, exhibit circularly
symmetric receptive fields, a strong preference for either increases or decreases in light intensity, and linear spatial summation (Denman and Contreras 2015; Grubb and Thompson
2003, 2005; Piscopo et al. 2013). Neurons in the superficial
(retinorecipient) layers of the rodent SC, on the other hand,
frequently exhibit irregularly shaped receptive fields, sensitivity to both increases and decreases in light intensity, and/or
responses to spatiotemporal patterns of light stimuli that are not
predictable from the linear summation of responses to small,
stationary stimuli (Drager and Hubel 1975; Gale and Murphy
2014; Humphrey 1968; Mooney et al. 1988).
To what extent, if at all, might differences in the output of
dLGN and SC neurons reflect differences in the retinal input
they receive? One hypothesis is that dLGN and SC neurons
exhibit distinct outputs despite receiving input from similar
sets of retinal ganglion cells (RGCs); indeed, distinct local
processing of shared retinal input might be necessary because
most (of the small number of) reconstructed rodent and cat
RGC axonal arbors innervate both the dLGN and SC (Bowling
and Michael 1980; Dhande et al. 2011). An alternative hypothesis, however, is that differences in the output of dLGN and SC
neurons reflect differences in the retinal input the neurons
receive (de Monasterio 1978; Rodieck and Watanabe 1993;
Schiller and Malpelli 1977). This is plausible because substantially more RGCs innervate one retinorecipient target than the
other (Dreher et al. 1985; Linden and Perry 1983; Martin 1986;
Perry et al. 1984).
Identifying the shared and distinct information that two brain
regions receive is important; it pinpoints where neural circuits
extract information about specific features of sensory stimuli.
Identifying shared and distinct sources of input is also difficult;
in the early visual system it requires 1) robust and specific
labeling and 2) functional characterization of populations of
SC-, dLGN-, and SC ⫹ dLGN-projecting RGCs. We satisfied
these requirements by determining the fraction of mouse RGCs
labeled via injection of rabies virus and/or retrogradely trans-
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Ellis EM, Gauvain G, Sivyer B, Murphy GJ. Shared and distinct
retinal input to the mouse superior colliculus and dorsal lateral
geniculate nucleus. J Neurophysiol 116: 602– 610, 2016. First published May 11, 2016; doi:10.1152/jn.00227.2016.—The mammalian
retina conveys the vast majority of information about visual stimuli to
two brain regions: the dorsal lateral geniculate nucleus (dLGN) and
the superior colliculus (SC). The degree to which retinal ganglion
cells (RGCs) send similar or distinct information to the two areas
remains unclear despite the important constraints that different patterns of RGC input place on downstream visual processing. To resolve
this ambiguity, we injected a glycoprotein-deficient rabies virus coding for the expression of a fluorescent protein into the dLGN or SC;
rabies virus labeled a smaller fraction of RGCs than lipophilic dyes
such as DiI but, crucially, did not label RGC axons of passage.
Approximately 80% of the RGCs infected by rabies virus injected into
the dLGN were colabeled with DiI injected into the SC, suggesting
that many dLGN-projecting RGCs also project to the SC. However,
functional characterization of RGCs revealed that the SC receives
input from several classes of RGCs that largely avoid the dLGN, in
particular RGCs in which 1) sustained changes in light intensity elicit
transient changes in firing rate and/or 2) a small range of stimulus
sizes or temporal fluctuations in light intensity elicit robust activity.
Taken together, our results illustrate several unexpected asymmetries
in the information that the mouse retina conveys to two major
downstream targets and suggest that differences in the output of
dLGN and SC neurons reflect, at least in part, differences in the
functional properties of RGCs that innervate the SC but not the dLGN.
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DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
ported fluorescent compounds into the SC and/or dLGN; subsequent electrophysiological recordings enabled quantitative
characterization and comparison of the light response properties of labeled RGCs. This approach revealed that many mouse
RGCs innervating the dLGN also innervate the SC; the same
approach also revealed, however, that the functional characteristics of RGC input to the SC and dLGN differ in several
important ways.
MATERIALS AND METHODS
excitation fluorescence laser scanning microscopy (Ultima; Prairie
Technologies). The Ti:sapphire laser (Ultra II; Coherent) was tuned to
⬃900 ⫾ 20 nm. The laser intensity was modulated by a Pockel’s cell
(Conoptics); laser intensity at the preparation was ⬍10 mW. The laser
was used only to identify fluorescent cells from which to record
electrophysiological signatures; the laser was shuttered while we
recorded responses of RGCs to visual stimuli.
Images of fixed tissue were acquired using a confocal microscope
(LSM-700; Carl Zeiss, Oberkochen, Germany) outfitted with a ⫻20,
⫻40, or ⫻63 objective; most images were composed of 1,024 ⫻ 1024
pixels. Images were stitched together, when necessary and appropriate, via Zen software (Carl Zeiss) or custom routines written in
MATLAB (The MathWorks). Labeled cells were counted manually
using the FIJI cell counter plugin (NIH; http://fiji.sc/Fiji).
Light stimuli and collection and analysis of electrophysiological
data. Stimuli were specified via custom software (written in openGL
by Anthony Leonardo and Calin Culineau) and generated via a
customized DMD projector (DepthQ; InFocus) with a refresh rate of
120 Hz. The output of the DMD 1,280 ⫻ 780 array was delivered to
the recording chamber via a dichroic mirror placed beneath the
condenser lens of an upright microscope (Zeiss); each pixel was ⬃1
␮m2. The light source, a broad-spectrum white LED (SugarCUBE;
Nathaniel Group, Vermont), was attenuated by a series of neutral
density filters. The maximum intensity of the light stimulus at the
preparation was ⬃3 ⫻ 106 photons·␮m⫺2·s⫺1. The background light
level delivered during most experiments was 1–10% of the maximum
intensity; i.e., well into the “photopic” range.
Cell-attached (or “loose seal”) patch-clamp recordings were performed with pipettes fabricated from thin-wall borosilicate glass
(Sutter). We filled the pipettes (4 – 8 M⍀) with Ames solution.
Electrophysiological signals were amplified and then low-pass filtered
at 3–5 kHz (Multiclamp 700B; Molecular Devices); data were digitized at 10 kHz (ITC-18; HEKA) and saved to disk via custom,
open-source software (Symphony; https://github.com/SymphonyDAS/symphony/). GFP- or mCherry-labeled cells exhibited a range of
soma sizes; we did not find it especially difficult to record from
smaller cells (in part because cell-attached recordings are less demanding than whole cell recordings). Moreover, we did not observe
any obvious differences in the response properties of nearby rabiesinfected and rabies-free 1) “alpha-like” or 2) On-Off direction-selective RGCs.
Electrophysiology data reported in this article were obtained from
a total of 28 mice; 6 –7 cells were characterized, on average, from
each mouse (range 1–28 cells). Analyses of light-evoked responses
were performed via procedures written in MATLAB. Light-evoked
responses were aligned to stimulus onset via measurement (with a
photodiode) of a signal that changed with each frame; spike times,
once aligned to the time of stimulus onset, were used to generate a
spike density function (SDF; Szucs 1998).
We began each experiment by determining how the cell’s response
varied as a function of stimulus contrast and duration; we then assayed
the response of the cell to five stimulus sizes (50 – 800 ␮m) using the
stimulus contrast that elicited slightly submaximal responses. Thereafter, using the stimulus size that produced the maximal response, we
assayed the response of a cell to stimuli moving in each of 8 directions
at a given speed of 800 ␮m/s. Finally, we moved the same-size
stimulus in a cell’s preferred direction at seven to eight different
speeds (that ranged from 50 to 3,200 ␮m/s).
Direction selectivity was computed as the vector sum of responses
(to stimuli moving in 8 different directions) normalized by the scalar
sum of responses; the amplitude of the normalized vector sum length
(NVSL) varies between 0 and 1, and the angle of the NVSL defined
the preferred direction of each cell. All dLGN-projecting On-Off
direction-selective RGCs and 19/20 SC-projecting On-Off directionselective RGCs had a NVSL value ⬎0.2. We did not always determine the orientation of the eye or the piece of retina cut from it; it was
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Mice, reagents, and surgical procedures. Experiments were performed on 5- to 12-wk-old c57bl6J mice of either sex. All procedures
were approved by the Institutional Animal Care and Use Committee
at the Janelia Research Campus. A subset of experiments used
transgenic mice: vGlut2-Cre (Vong et al. 2011), Ai14 (Madisen et al.
2010), and Hb9::eGFP (Arber et al. 1999; Trenholm et al. 2011).
We used stereotaxic injection of glycoprotein (G)-deleted rabies
virus and/or DiO/DiI/DiD (Life Technologies, Grand Island, NY) to
retrogradely label RGCs from the SC and/or dLGN. Rabies virus was
generated by the molecular biology facility at the Janelia Research
Campus; the virus drove expression of green fluorescent protein
(GFP) or mCherry. Exactly the same rabies virus was used to infect
the axon terminals of RGCs in the dLGN and SC, ruling out the
possibility that observed differences in the functional characteristics
of SC- and dLGN-projecting RGCs were a consequence of viral
tropism.
Stereotaxic coordinates for SC injections were 0 – 0.5 mm rostral
from lambda, 0.3–1.0 mm lateral from the midline, and 0.9 –1.2 mm
deep from the pial surface. Coordinates targeting the dLGN were
1.2–1.6 mm rostral to lambda, 2.2–2.3 mm lateral to the midline, and
2.5–2.7 mm below the pial surface. In nearly all cases we injected
50 –100 nl of virus or DiO/DiI/DiD along each injection tract. We
regularly ejected reagents at three different depths along a tract (each
injection site was separated by at least 50 ␮m) to label RGC axons
distributed throughout the dorsal ventral axis of a given retinorecipient area. We did this for two reasons. First, from a practical point of
view, there is little consequence of injecting too deep. Second, and
perhaps more importantly, we thought it important to distribute
reagents throughout the “shell” and the “core” of the dLGN and
through the entire depth of the retinorecipient layers of the SC. We
injected a small volume (⬍10 nl) of a given reagent at only one depth
in a small subset of experiments (shown in Fig. 1B).
Experiments were performed ⬎6 days after injection of DiO/DiI/
DiR and 4 – 6 days after injection of rabies virus. In cases in which
both reagents were injected into the same animal, DiO/DiI/DiR was
injected into the SC first (because transport of DiO/DiI/DiR from the
SC takes longer than virus-mediated expression of fluorescent proteins). Three to 5 days later, rabies virus was injected into the dLGN;
retinal tissue was extracted 4 – 6 days after rabies had been injected
into the dLGN.
After dark-adapting overnight, animals were killed via cervical
dislocation; this and all subsequent procedures were performed under
infrared (⬎900 nm) illumination. The eyes were dissected and stored
in a light-tight container in bicarbonate-buffered Ames solution (Sigma-Aldrich, St. Louis, MO) equilibrated with carbogen (95% O2-5%
CO2). The cornea, lens, and vitreous were removed mechanically
from each eye. Subsequently, a section of the eye cup was cut with a
scalpel blade and the retina isolated from the pigment epithelium. The
retina was placed ganglion cell side up on a piece of filter paper
(Anodisc13; Whatman); the filter paper was then secured to a glassbottom recording chamber via grease. The retina was held to the filter
paper via nylon wires stretched across a platinum scaffold. Warm
(30 –34°) equilibrated Ames solution perfused the recording chamber
at a rate of ⬃6 ml/min.
Multiphoton excitation and confocal scanning microscopy. Retrogradely labeled RGCs in living tissue were identified via multiphoton
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DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
therefore impossible to determine the eye- or head-centric coordinates
to which direction- or orientation-selective RGCs responded best.
Response duration is the integral of the SDF over a 500-ms window
starting at the response latency (⬎0.1 ⫻ peak response for at least 50
ms) divided by the peak response and window duration. A cell’s “best
size” reflects the stimulus size that resulted in the largest peak
response; best size fit is the same for a gamma function fit (Nover et
al. 2005) of the size tuning curve. Size tuning width and speed tuning
width are the normalized area (integral/peak) of the size tuning and
speed tuning curve, respectively. Size tuning and speed tuning fit are
the same for a gamma function fit of the appropriate relationship.
RESULTS
Eighty-five to ninety percent of mouse RGCs project to the
SC. To estimate the fraction of RGCs that project to a given
retinorecipient area requires one to first identify RGCs. This is
nontrivial because the ganglion cell layer of the mammalian
retina contains both RGCs and a substantial number of amacrine cells, i.e., GABA, and/or glycinergic interneurons that do
not project to the brain.
Many RGCs, and few if any amacrine cells, express vesicular glutamate transporter 2 (vGlut2; Johnson et al. 2003; Land
B
A
C
DAPI TdTomato DiO
D
mCherry
DiI
GFP
GFP
DiD
DiD
S
D
M
L
1.0
250 m
120
180
Angle (°)
240
0.5
0.0
n= 3217 / 5828
0.0
0.5
TdT cells / DAPI cells
250 m
1000
0
1000
Distance to Optic
Nerve Head ( m)
50 m
DiD cells / GFP cells
DiO cells / TdT cells
50 m
n= 2844 / 3217
1.0
n= 220 / 273
0.5
0.0
0
50
GFP cells
Fig. 1. The vast majority of RGCs, and the vast majority of dLGN-projecting RGCs, innervate the SC. A: 88% of mouse RGCs are retrogradely labeled from
the SC. Top, confocal image of the ganglion cell layer of vGlut-Cre ⫻ Ai14 mouse retina ⬃7 days after ⬃100 nl of DiO were injected into the SC. DAPI (blue)
labeled all cells, TdTomato (purple) is expressed in RGCs, and DiO (green) labels RGCs retrogradely labeled from the SC. Bottom, each circle represents, for
a given retina, the fraction of RGCs labeled with DiO (y-axis) vs. the fraction of ganglion cell layer cells expressing TdTomato (x-axis). B, top: fluorescence
image of an SC in which an unusually small (⬍10 ␮l) volume of DiI was injected medially (M) and a small volume of DiD was injected laterally (L). S and
D denote the superficial and deep SC, respectively. Bottom, fluorescence image of the retina contralateral to the SC shown above. C, top: fluorescence image
of a retina from an animal in which ⌬G-Rabies_mCherry and ⌬G-Rabies_GFP were injected into the rostral and caudal SC, respectively. Gray circle denotes
the location of the optic nerve head; purple and green circles denote 2D Gaussian fits to the channels capturing mCherry and GFP fluorescence emission,
respectively. The angle separating the center of the 2D Gaussian fits to the mCherry and GFP fluorescence emission in each of 6 eyes is shown at bottom. Bottom,
the absolute distance from the optic nerve head to the center of the two 2D Gaussian fits in each of the 6 eyes; error bars indicate 2 times the standard deviation
of the fits. D: many dLGN-projecting RGCs also innervate the SC. Top, confocal image of an area of retina from an animal in which ⌬G_Rabies-GFP was injected
into the dLGN (green) and DiD (⬃100 nl) was injected into the SC (purple). Bottom, each circle represents, for a given retina, the fraction of dLGN-projecting
RGCs that were also DiD positive (y-axis); lines link data obtained from the 2 eyes of a given mouse. The red square and error bars represent the mean ⫾ SE
across 7 retinas. Note that there were many GFP-positive cells in areas of the retina that exhibited sparse/weak DiD labeling; these RGCs/areas were excluded
from analysis.
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et al. 2004; Sherry et al. 2003). Therefore, to label RGCs
selectively, we crossed transgenic mouse lines in which Cre
recombinase is expressed in vGlut2-expressing cells (Vong et
al. 2011), and the red fluorescent protein TdTomato is expressed in cells that express Cre recombinase (Ai14; Madisen
et al. 2010). SC-projecting RGCs were identified by injecting
retrogradely transported lipophilic fluorescent compounds such
as DiO into the SC; as in our previous work (Gauvain and
Murphy 2015), DiO was targeted to the caudal half of the SC
to avoid labeling retinorecipient nuclei just rostral to the SC.
Retinal tissue collected 7⫹ days after DiO was injected into
the SC of vGlut2-Cre ⫻ Ai14 animals supports several conclusions. First, because DiO only labeled TdTomato-positive
cells, many, if not all, RGCs express TdTomato in vGlut2-Cre
⫻ Ai14 animals; we would expect to see DiO in cells lacking
TdTomato otherwise. Second, because DiO never labeled a cell
lacking TdTomato, the absence of TdTomato almost certainly
indicates that a cell is an amacrine cell. Third, RGCs represent
a slight majority of cells in the mouse ganglion cell layer; an
average of 55% of all ganglion cell layer cells expressed
TdTomato (Fig. 1A, bottom, x-axis; range 53.8 –56.6% across 3
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DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
of GFP-expressing cells that also exhibited DiI/DiD; focusing
on the areas most densely labeled with DiI or DiD increased
the confidence with which we could interpret the absence of
retrograde label in an RGC as evidence that the RGC did not
project to the SC (see Fig. 1A). We found that DiI/DiD labeled,
on average, ⬎80% of GFP-expressing RGCs (range: 52–96%
across 7 retinas from 4 animals; Fig. 1D). Thus most, but not
all, of the information that the retina conveys to the dLGN is
also sent to the SC.
Functional characterization and comparison of On-Off direction-selective RGCs retrogradely labeled from the dLGN
and SC. The data presented in Fig. 1 do not, on their own,
resolve the degree to which the retina sends similar or distinct
information to the dLGN and SC. The ⬃20% of dLGNprojecting RGCs that do not extend an axon collateral to the SC
might, for example, be functionally distinct from the ⬃80%
that do. Moreover, anatomical information indicates that some
mouse RGCs synapse within the SC but not the dLGN (Dhande
et al. 2011); the number and functional properties of such “SC
only” RGCs are unknown.
We reasoned that the response properties of RGCs labeled
from the dLGN and SC should be similar if most RGCs
innervate both the dLGN and SC; by the same logic, the
response properties of RGCs labeled from the dLGN and SC
should be different if 1) a significant fraction of RGCs innervate one area but not the other and 2) RGCs targeting only one
area respond to distinct/specific subsets of stimulus characteristics. To test these hypotheses, we identified RGCs infected
from the SC or dLGN via multiphoton fluorescence microscopy and recorded the responses of these cells to a number of
visual stimuli. In each of 192 labeled RGCs, we assayed how
action potential generation varied as a function of stimulus
contrast, size, duration, direction and speed of motion, and
temporal modulation of luminance; this information enabled us
to distinguish several functional classes of mammalian RGC
(reviewed in Sanes and Masland 2015).
Figure 2A shows the response of a SC-projecting RGC to 1)
a bright circle (of three different diameters) on a dark background and 2) different directions of movement of the stimulus
size that produced a maximal response. The cell responds to
the onset and offset of the stationary light stimulus (Fig. 2A1)
and strongly prefers stimuli moving in a subset of directions
(Fig. 2A2).
This cell exhibits most, if not all, of the characteristics of one
of the most readily identified/studied classes of mammalian
RGC; i.e., On-Off direction-selective (DS) RGCs (reviewed in
Vaney et al. 2012). As predicted from previous results (Huberman et al. 2009; Kay et al. 2011; Kim et al. 2010), we found
that On-Off DS RGCs were retrogradely labeled from the
dLGN and SC. However, On-Off DS RGCs comprised a
substantially larger fraction of the RGCs retrogradely labeled
from the SC (20/103; Fig. 2B1, right) than from the dLGN
(10/89; Fig. 2B1, left). We found limited evidence for projection-specific differences in the functional properties of On-Off
DS RGCs (Kay et al., 2011; Rivlon-Etzion et al. 2011); dLGNand SC-projecting On-Off DS RGCs exhibited similar degrees
of direction selectivity (P ⬎ 0.3 via Wilcoxon-Mann-Whitney
rank test; Fig. 2B1) and responded best to overlapping sizes and
velocities of stimuli (P ⬎ 0.4 in both cases; Fig. 2B2). However, we noticed in this dataset and a previous one from our
group (Gauvain and Murphy 2015) that a small but noticeable
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retinas from 3 mice). Fourth, the vast majority of mouse RGCs
innervate the SC; in areas of the retina densely labeled from the
SC, ⬃88% of TdTomato-positive cells were also DiO positive
(in each of the same 3 retinas: Fig. 1A, bottom, y-axis; range
86.7– 88.9%).
Approximately 80% of dLGN-projecting RGCs also innervate the SC. The axons of SC-projecting RGCs pass through
the dLGN (see, for example, Morin and Studholme 2014). To
identify RGCs that innervate the dLGN but not the SC, as well
as the fraction of dLGN-projecting RGCs that send an axon
collateral to the SC, requires one to use reagents that label cells
that synapse in the dLGN without labeling cells that simply
send an axon through/near the same area; commonly used
reagents such as DiO/DiI, horseradish peroxidase, or fluorophore-conjugated latex microspheres or cholera toxin are not
sufficient/suitable.
Several reports suggest that rabies virus is taken up preferentially if not exclusively at presynaptic terminals (reviewed in
Callaway and Luo 2015; Ugolini 2010). To test this hypothesis,
we injected a G-deleted rabies virus (Wickersham et al. 2007)
coding for the expression of mCherry into the rostral SC and
the same virus coding for expression of GFP into the caudal
SC. If the virus does not infect axons of passage, then 1) GFPand mCherry-expressing RGCs should occupy separate areas
of the retina, because RGCs innervating the rostral and caudal
SC are located in the temporal and nasal retina, respectively
(Siminoff et al. 1966; Simon and O’Leary 1992); and 2) RGCs
innervating the caudal SC should never express mCherry
despite sending an axon through the rostral SC.
We found that GFP- and mCherry-expressing RGCs nearly
always occupied opposite sides of the retina (Fig. 1C, top).
Indeed, ⬃164° separated the vectors linking the optic nerve
head to the center of two-dimensional (2D) Gaussian fits to
GFP- and mCherry-expressing RGC populations (n ⫽ 6 eyes
from 3 animals; Fig. 1C). The absolute distance between the
centers of the two populations of RGCs (1,757 ⫾ 101 ␮m) was
an order of magnitude larger than the standard deviation of the
2D Gaussian fit to either population (Fig. 1C, bottom), and no
GFP-expressing cells were within two standard deviations of
the center of the area occupied by mCherry-expressing cells.
Moreover, mCherry-expressing RGCs were always tightly
clustered together on the temporal side of the optic nerve head;
i.e., they did not occupy (nasal) areas of the retina densely
labeled from the caudal SC. Together, these results indicate
that G-deleted rabies virus is unlikely to infect RGC axons of
passage.
The results of experiments shown in Fig. 1C indicate that
rabies virus can be used to infect RGCs that synapse in the
dLGN without labeling axons that simply pass through the
region on their way to the SC. Therefore, to estimate
the fraction of dLGN-projecting RGCs that innervate the SC,
we first injected DiI or DiD bilaterally into the caudal SC of a
given animal. Three to 5 days later we injected rabies virus
coding for the expression of GFP bilaterally into the dLGN of
the same animal; reagents were injected in both regions via
multiple tracts and at multiple depths to 1) label RGCs axons
at different planes along the dorsal-ventral axis, 2) maximize
the number of labeled RGCs, and 3) maximize the retinal area
in which RGCs exhibited GFP and DiI/DiD labeling.
After waiting 4 – 6 days for GFP expression, we quantified
(in areas of the retina densely labeled from the SC) the fraction
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A1
A2
B1
B2
200 m
50
0
400 m
250 ms
0 120 240
Movement Direction (°)
Best Size ( m)
100 m
100
0.5
NVSL
Peak APs / s
300
0.0
n=10
n=20
dLGN SC
200
100
0
dLGN
SC
0
1
2
Best Speed (mm/s)
subset of SC-projecting On-Off DS RGCs respond best to
unusually high stimulus speeds. Together, our results are most
consistent with the idea that many individual On-Off DS RGCs
innervate both the dLGN and SC, whereas some innervate only
the SC.
Differences in retinal input to the dLGN and SC from Off
and On RGCs. On-Off DS RGCs represent only a subset of the
total retinal input to the brain. We therefore performed a
similar analysis for cells that responded to the offset of a light
stimulus; i.e., Off RGCs. To distinguish different types of Off
RGCs and compare the characteristics and relative abundance
of these subtypes, we quantified the dynamics of action potential generation 1) following a 500-, 1,000-, or 2,000-ms step
increase in light intensity and 2) in response to sinusoidal
modulation of light intensity over time. This approach has
helped distinguish functionally distinct groups of RGCs in a
number of species, including mice (Baden et al. 2016; Farrow
and Masland 2011; Margolis and Detwiler 2007; Murphy and
Rieke 2006; Pang et al. 2003).
Off RGCs comprised a similar fraction of dLGN (19/89)and SC (27/103)-projecting RGCs (P ⬎ 0.3 via ␹2 test) and
exhibited a broad diversity of response properties. One characteristic that varied between neurons was the degree to which
neurons’ responses were sustained or transient following an
abrupt (“step”) decrease in light intensity (Fig. 3A). We found
that Off RGCs exhibiting sustained changes in firing rate were
encountered more frequently in the dLGN-projecting population of RGCs (11/19 vs. 8/27; P ⬍ 0.04 ␹2 test). Like On-Off
DS RGCs (Fig. 2), sustained Off RGCs exhibited similar
functional characteristics whether they were labeled from the
dLGN or SC; i.e., the spontaneous rate, response duration, and
size tuning width were not significantly different between
sustained Off RGCs labeled from the dLGN and SC (P ⬎ 0.25
in each case; Fig. 3B, left).
Off RGCs exhibiting sustained responses maintain elevated
rates of action potential generation well after an abrupt decrease in light intensity (Fig. 3A, left) and during the phases of
a sinusoidally modulated stimulus in which light intensity is
low (Fig. 3C, left). Action potential generation returns to zero
or near-zero values much more rapidly, by comparison, in Off
RGCs exhibiting transient responses to the same stimuli (Fig.
3, A and C, middle and right columns). The fraction of Off
RGCs exhibiting transient responses to light stimuli was similar in the SC (15/27)- and dLGN (8/19)-projecting populations
of RGCs (P ⬎ 0.3, ␹2 test). However, the ratio of transient to
sustained Off RGCs was twice as large in the SC-projecting
population of RGCs. To our surprise, dLGN- and SC-projecting Off transient RGCs exhibited significant functional differences. In particular, Off transient RGCs in the population
retrogradely labeled from the dLGN generated more action
potentials in darkness (Fig. 3B, right; 10.7 ⫾ 6.3 vs. 1.8 ⫾ 2.9;
means ⫾ SD; P ⬍ 0.001) and responded robustly to a larger
range of stimulus sizes (P ⬍ 0.011). Indeed, 4/5 of the Off
RGCs with size tuning widths ⬍500 ␮m were retrogradely
labeled from the SC (Fig. 3D); the stimulus size to which these
cells responded best was generally, although not always, ⱕ200
␮m. Moreover, the frequency at which responses to sinusoidal
modulation of light intensity became half maximal, the corner
“cutoff” frequency, was substantially lower in SC- than dLGNprojecting transient Off RGCs (Fig. 3, C and D). Together,
these data suggest that the SC receives input from at least one
class of transient Off RGC that does not innervate the dLGN;
i.e., one that responds best to smaller stimuli and a smaller
range of temporal fluctuations in light intensity. The same
results suggests that Off Transient RGCs with moderate activity in darkness and broad size tuning are substantially more
common in the dLGN- vs. SC-projecting pool of RGCs.
Several results indicate that On RGCs exhibit similar asymmetries. First, On RGCs comprised a substantially higher
fraction of the RGCs labeled from the dLGN than SC (45/89
vs. 36/103; P ⬍ 0.03 via ␹2 test). Second, as with Off RGCs,
On RGCs exhibiting sustained responses were more common
in the pool of dLGN-projecting RGCs, whereas those exhibiting transient responses were more common in the SC-projecting RGC population (P ⬍ 0.01; Fig. 4, A and B). Third, the
population of RGCs labeled from the SC exhibited significantly narrower size tuning (P ⬍ 0.001). Indeed, 8 of the 9
cells that responded (transiently) only to small stimuli were in
the SC-projecting population of RGCs (Fig. 4A3; quadrant 3 of
Fig. 4B). Collectively, our results suggest that the SC receives
input from many of the types of RGC that innervate the dLGN
in addition to several types that largely avoid the dLGN, e.g.,
Off and On RGCs that exhibit transient responses and/or
respond to a limited range of (generally small) stimulus sizes.
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Fig. 2. Functional characteristics of On-Off direction-selective (DS) RGCs retrogradely labeled from the dLGN or SC. A1: average response of a representative
On-Off DS RGC to the presentation of a bright spot with a diameter of 100, 200, or 400 ␮m. Vertical scale bar at bottom right represents 100 action potentials
(APs)/s. A2: average rate of AP generation of the same cell to movement of a 200-␮m spot (through the center of the cell’s receptive field) in 8 different directions
at 800 ␮m/s, i.e., ⬃30°/s. B1: the degree of direction selectivity (quantified via the normalized vector sum length, NVSL) in each cell. B2: the interpolated best
stimulus size (y-axis) and interpolated best stimulus velocity (x-axis) for each of the On-Off DS RGCs labeled from the dLGN (filled circles) and SC (open
squares). Histograms formed by separately collapsing values along the x- and y-axes and then binning are shown at right and top, respectively; open bars
summarize the SC data whereas lines connecting filled circles summarize the LGN data.
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DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
607
B
A
1
Response Duration
0
Size Tuning
Width ( m)
100 m
Response
Duration:
200 m
400 m
800 m
500
dLGN
SC
300
0
Transient
dLGN
Transient
SC
Peak APs / s
D
1 Hz
2 Hz
4 Hz
0
10
20
20
40
Spontaneous Firing Rate (APs / s)
Sustained
Transient
100
dLGN
SC
Offset SC
10
1
500 ms
10
1
Frequency (Hz)
10
Fig. 3. Functional characteristics of Off RGCs retrogradely labeled from the dLGN or SC. A: similarities and differences in the response properties of Off RGCs
labeled from the dLGN and SC. The histogram at top shows the number of RGCs as a function of the RGCs’ response duration; the y-axis is the cell count and
the x-axis represents response duration values (binned in increments of 0.05). Responses of 3 representative RGCs to the presentation of a 100-, 200-, 400-, and
800-␮m bright spot on a dark background are shown at bottom. Vertical scale bar in this and all subsequent panels represents 200 APs/s. B: the size tuning width
vs. spontaneous firing rate for each Off RGC. Cells that exhibited sustained and transient changes in firing rate following a decrease in light intensity are shown
at left and right, respectively. Data from RGCs labeled from the dLGN and SC are represented by filled circles and open squares, respectively. C: response of
the same representative Off RGCs to 1-, 2-, and 4-Hz modulation of a large, spatially uniform spot of light. D: peak firing rate (⫾SD) as a function of stimulus
frequency for sustained Off RGCs (left) and transient Off RGCs (right) labeled from the dLGN (solid line, filled circles) or SC (solid line, open squares). The
dashed gray trace at right was formed by vertically shifting the SC data by 35 APs/s.
DISCUSSION
To what extent might differences in retinal input underlie
differences in the output of dLGN and SC neurons? We find
that SC neurons have access to much of the information the
retina sends to the dLGN but not necessarily the converse; the
same results suggest that RGCs that innervate the SC but avoid
the dLGN frequently exhibit transient responses and/or sensitivity to small stimuli.
Structure/anatomy. A slight majority of cells in the ganglion
cell layer of vGlut2-Cre ⫻ Ai14 mice expressed TdTomato.
DiO injected into the SC of these animals never labeled a
ganglion cell layer cell that lacked TdTomato; this 1) argues
against the possibility that a substantial fraction of RGCs in the
retina of vGlut2-Cre ⫻ Ai14 animals lack TdTomato and 2)
indicates that many, if not all, amacrine cells lack TdTomato.
On the other hand, the density of TdTomato labeling prevented
us from determining whether each putative RGC had an axon;
we cannot, therefore, rule out the possibility that TdTomato
might be expressed spuriously in a small number of amacrine
cells. Indeed, our estimate of the fraction of RGCs in the mouse
ganglion cell layer, which is based on the fraction of cells that
express TdTomato, is slightly higher than previous estimates
from Jeon et al. (1998; 41%) and Schlamp et al. (2013; 51%).
Our results, like those of previous studies (Chalupa and
Thompson 1980; Vaney et al. 1981), suggest that the vast
majority of mouse RGCs project to the SC. The observation
that ⬃88% of RGCs are retrogradely labeled from the mouse
SC could underestimate the true fraction of SC-projecting
RGCs, however, if DiO did not robustly label axons innervating the area in which it was injected. We think this is unlikely
for at least two reasons. First, ⬎97% of the On-Off DS RGCs
tuned to anterior motion, i.e., 83/85 of the GFP-expressing
RGCs examined in four retinae from two Hb9::eGFP transgenic mice (Arber et al. 1999; Trenholm et al. 2011), were
retrogradely labeled following injection of DiI into the SC
(data not shown). Second, existing evidence supports the idea
that several types of RGC avoid the SC altogether (Buhl and
Peichl 1986; Gauvain and Murphy 2015; Schmidt et al. 2011;
Yonehara et al. 2008).
Conversely, 88% could represent an overestimate if DiI or
DiO labels cells that do not innervate the SC. We think this is
unlikely for several reasons. First, as in our previous work
(Gauvain and Murphy 2015), DiO was targeted to the caudal
half of the SC to avoid labeling retinorecipient nuclei just
rostral to the SC. Second, several results indicate that DiI/DiO
taken up by SC-projecting RGCs did not spread readily to
nearby cells that do not innervate the SC: 1) neither DiI nor
DiO was ever observed in amacrine cells, e.g., cells in the
retina of vGlut2-Cre ⫻ Ai14 mice that lacked TdTomato (Fig.
1A) or cells in the retina of Chat-Cre ⫻ Ai32 mice that
expressed eYFP (starburst amacrine cells; data not shown); 2)
DiO labeled ⬍90% of vGlut2-positive/TdTomato-positive
cells in the most densely labeled area of each piece of retina
examined; and 3) injecting small volumes of DiI and DiD into
the medial and lateral aspects of the same SC, respectively,
labeled RGCs in separate areas of the retina (Fig. 1B); i.e., DiI
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C
<0.5
700
250 ms
Sustained
dLGN / SC
>0.5
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608
DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
A1
Sustained
dLGN
A2
A3
Transient
SC
Transient
SC
100 m
200 m
400 m
800 m
250 ms
Size Tuning Width ( m)
B
1
2
dLGN
SC
3
500
0
1.0
did not spread from RGCs innervating one part of the SC to
RGCs innervating another part of the SC. These results indicate that the family of lipophilic dyes that includes DiO, DiI,
and DiD does not spread to amacrine cells and spreads weakly,
if at all, between RGCs.
Previous studies suggest that 25–50% of rodent/rabbit RGCs
innervate the dLGN (Dreher et al. 1985; Linden and Perry
1983; Martin 1986; see, however, Coleman et al. 2009). More
precise estimates require one to 1) label all the dLGN-projecting RGCs 2) without labeling any of the RGC axons that pass
near (but do not synapse within) the dLGN. Our control
experiments (Fig. 1C) indicate that G-deleted rabies virus
satisfies only the second of these criteria; other data indicates
that lipophilic dyes satisfy the first criterion but not the second.
The same technical constraints complicate efforts to determine the fraction of SC-projecting RGCs that also innervate
the dLGN. It was possible, however, to determine the fraction
of dLGN-projecting RGCs innervating the SC. The high percentage of dLGN-projecting RGCs retrogradely labeled from
the SC (Fig. 1D) suggests that SC neurons have access to the
vast majority of retinal input sent to the dLGN. Functional
evidence (see below) suggests that the converse is unlikely.
Function/electrophysiology. Retrograde transport or transgenic expression of fluorophores facilitates identification of the
RGCs projecting to retinorecipient brain regions. However, in
0.5
Response Duration
0.0
the absence of a transgenic line labeling each class of mouse
RGC completely and uniquely, the only way to assay the
relative abundance of different classes of RGCs innervating
one or more regions is to first retrogradely label (or antidromically activate) RGCs and then characterize their responses to
visual stimuli.
Many of the retrogradely labeled RGCs we characterized
could be distinguished from one another on the basis of their
responses to a small, relatively simple set of visual stimuli.
Indeed, ⬎80% of dLGN- and SC-projecting RGCs fell into one
of the six groups we used, i.e., On-Off DS, sustained and
transient Off, sustained On, transient On, and a group of On
RGCs that exhibit transient responses to small-diameter stimuli. The latter group of RGCs likely includes the “W3” RGCs
characterized previously (Kim et al. 2010; Zhang et al. 2012);
such RGCs share some similarities to local edge detector
(LED) RGCs in the rabbit retina (Levick 1967; van Wyk et al.
2006).
Categorizing cells into these groups and comparing the
relative abundance of RGCs in the distinct groups revealed
qualitative differences in retinal input to the dLGN and SC. In
particular, On-Off DS, transient Off, transient On, and On
RGCs exhibiting transient responses and small spatial receptive fields were substantially more common in the SC-projecting than dLGN-projecting population of RGCs; correspond-
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Fig. 4. Functional characteristics of On RGCs retrogradely labeled from the dLGN or SC. A1: average
response of a representative sustained On RGC to the
presentation of a bright spot of increasing size; this
cell, and many others like it, was retrogradely labeled
from the dLGN. Vertical scale bar in this and all
subsequent panels represents 100 APs/s. A2 and A3:
same as in A1 for transient On RGCs (A2) and the
group of RGCs that exhibits transient responses and
selectivity for small stimuli retrogradely labeled
from the SC (A3). B: scatter plot showing the response duration (x-axis) and size tuning width (yaxis) for each On RGC labeled from the dLGN (filled
circles) and SC (open squares). Histograms formed
by separately collapsing values along the x-and yaxes and then binning are shown at right and top,
respectively; open bars summarize the SC data
whereas lines connecting filled circles summarize the
LGN data.
Rapid Report
DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
ACKNOWLEDGMENTS
We are indebted to Sarah Lindo for stereotaxic surgery support, Kim Ritola
and the Janelia Viral Services Resource for generating viral reagents, and
Kevin Briggman, Adam Bleckert, and Sam Gale for multiple helpful suggestions throughout the course of the study. Georg Keller, Sonja Hofer, Tony
Azevedo, and Corbett Bennett provided valuable comments on an early version
of the manuscript.
GRANTS
Financial support for this work was provided by the Howard Hughes
Medical Institute (HHMI). E. M. Ellis was part of the HHMI Medical Fellows
program and was funded by the Foundation Fighting Blindness. B. Sivyer
received support from an Australian government National Health and Medical
Research Council C. J. Martin Biomedical Fellowship.
DISCLOSURES
No conflicts of interest, financial or otherwise, are declared by the authors.
AUTHOR CONTRIBUTIONS
E.M.E., G.G., and B.S. performed experiments; E.M.E., G.G., B.S., and
G.J.M. analyzed data; E.M.E., G.G., B.S., and G.J.M. interpreted results of
experiments; E.M.E., G.G., B.S., and G.J.M. edited and revised manuscript;
E.M.E., G.G., B.S., and G.J.M. approved final version of manuscript; E.M.E.,
G.G., B.S., and G.J.M. conception and design of research; G.J.M. prepared
figures; G.J.M. drafted manuscript.
REFERENCES
Ahmadlou M, Heimel JA. Preference for concentric orientations in the mouse
superior colliculus. Nat Commun 6: 6773, 2015.
Andermann ML, Kerlin AM, Roumis DK, Glickfeld LL, Reid RC. Functional specialization of mouse higher visual cortical areas. Neuron 72:
1025–1039, 2011.
Arber S, Han B, Mendelsohn M, Smith M, Jessell TM, Sockanathan S.
Requirement for the homeobox gene Hb9 in the consolidation of motor
neuron identity. Neuron 23: 659 – 674, 1999.
Baden T, Berens P, Franke K, Roman Roson M, Bethge M, Euler T. The
functional diversity of retinal ganglion cells in the mouse. Nature 529:
345–350, 2016.
Bowling DB, Michael CR. Projection patterns of single physiologically
characterized optic tract fibres in cat. Nature 286: 899 –902, 1980.
Buhl EH, Peichl L. Morphology of rabbit retinal ganglion cells projecting to
the medial terminal nucleus of the accessory optic system. J Comp Neurol
253: 163–174, 1986.
Callaway EM, Luo L. Monosynaptic circuit tracing with glycoprotein-deleted
rabies viruses. J Neurosci 35: 8979 – 8985, 2015.
Chalupa LM, Thompson I. Retinal ganglion cell projections to the superior
colliculus of the hamster demonstrated by the horseradish peroxidase technique. Neurosci Lett 19: 13–19, 1980.
Coleman JE, Law K, Bear MF. Anatomical origins of ocular dominance in
mouse primary visual cortex. Neuroscience 161: 561–571, 2009.
De Monasterio FM. Properties of ganglion cells with atypical receptive-field
organization in retina of macaques. J Neurophysiol 41: 1435–1449, 1978.
Denman DJ, Contreras D. Complex effects on in vivo visual responses by
specific projections from mouse cortical layer 6 to dorsal lateral geniculate
nucleus. J Neurosci 35: 9265–9280, 2015.
Dhande OS, Hua EW, Guh E, Yeh J, Bhatt S, Zhang Y, Ruthazer ES,
Feller MB, Crair MC. Development of single retinofugal axon arbors in
normal and beta2 knock-out mice. J Neurosci 31: 3384 –3399, 2011.
Drager UC, Hubel DH. Responses to visual stimulation and relationship
between visual, auditory, and somatosensory inputs in mouse superior
colliculus. J Neurophysiol 38: 690 –713, 1975.
Dreher B, Sefton AJ, Ni SY, Nisbett G. The morphology, number, distribution and central projections of class I retinal ganglion cells in albino and
hooded rats. Brain Behav Evol 26: 10 – 48, 1985.
Farrow K, Masland RH. Physiological clustering of visual channels in the
mouse retina. J Neurophysiol 105: 1516 –1530, 2011.
Feinberg EH, Meister M. Orientation columns in the mouse superior colliculus. Nature 519: 229 –232, 2015.
Field GD, Chichilnisky EJ. Information processing in the primate retina.
Annu Rev Neurosci 30: 1–30, 2007.
Gale SD, Murphy GJ. Distinct representation and distribution of visual
information by specific cell types in mouse superficial superior colliculus. J
Neurosci 34: 13458 –13471, 2014.
Garrett ME, Nauhaus I, Marshel JH, Callaway EM. Topography and areal
organization of mouse visual cortex. J Neurosci 34: 12587–12600, 2014.
Gauvain G, Murphy GJ. Projection-specific characteristics of retinal input to
the brain. J Neurosci 35: 6575– 6583, 2015.
J Neurophysiol • doi:10.1152/jn.00227.2016 • www.jn.org
Downloaded from http://jn.physiology.org/ by 10.220.33.1 on June 17, 2017
ingly, sustained Off and On RGCs comprised a higher fraction
of the dLGN-projecting population of RGCs. Retinal input to
the dLGN and to the SC shared at least one characteristics: On
RGCs were substantially more common than Off or On-Off
RGCs in both the dLGN- and SC-projecting populations.
However, we know of no evidence to strongly support or
dispute the idea that rabies labels different types of RGCs
equally well. Likewise, we know of no study that identifies an
RGC type in the mouse that preferentially synapses within the
SC. Our results strongly suggest that the axons of many
“W3-like” RGCs pass through the dLGN but form synapses
predominantly/exclusively in the SC; we hope/expect that
follow-up studies will test this hypothesis directly.
The retina contains more than the six functional classes of
RGCs we described/distinguished in this study. Previous work
clustered mouse RGCs into 12 distinct groups on the basis of
electrophysiological responses to a panel of visual stimuli
(Farrow and Masland 2011). A more recent study clustered
mouse RGCs into ⬎30 classes on the basis of responses
assayed via changes in the emission of Ca2⫹-sensitive fluorophores (Baden et al. 2016); complementing physiological characterization of individual cells with analysis of the cells’
somatodendritic morphology substantially increased the discriminability of different types of RGCs in that study and
others like it. In our case, the density of cells labeled via GFP
or mCherry was frequently too high to permit reconstruction of
individual functionally characterized cells’ dendritic arbors.
We could have focused on areas with sparser labeling but
chose, instead, to sample RGCs in densely labeled areas; this
enabled a more representative sample of the classes of RGCs
that “tile” (or form a mosaic in) a given area of the retina.
The class of RGC that tiles the primate retina most densely,
midget RGCs, subserves high-resolution vision and projects
largely, if not exclusively, to the dLGN (reviewed in Field and
Chichilnisky 2007). Although the mechanisms that govern size
selectivity in mouse RGCs remain unclear, our results indicate
the mouse RGCs that respond best to a limited range of
(generally small) stimulus sizes innervate the SC but largely
avoid the dLGN. Our results further indicate that abrupt
changes in light intensity produce substantially more transient
changes in action potential firing in the SC-projecting pool of
mouse RGCs. The first observation might explain why neurons
in the primate SC and mouse dLGN generally respond best to
larger stimuli. The second observation suggests that differences in the dynamics of dLGN and SC neuronal responses
might be a consequence of differences in the dynamics of
retinal input that neurons in the two areas receive; differences
in local circuitry and/or intrinsic biophysical characteristics
could, of course, also contribute to differences in the output of
dLGN and SC neurons. Direct tests of these hypotheses are
challenging but important; they promise to reveal how different
combinations of network, synaptic, and/or cellular characteristics transform sensory signals in different neural pathways.
609
Rapid Report
610
DIVERGENCE OF RETINAL INFORMATION TO THE BRAIN
Perry VH, Oehler R, Cowey A. Retinal ganglion cells that project to the
dorsal lateral geniculate nucleus in the macaque monkey. Neuroscience 12:
1101–1123, 1984.
Piscopo DM, El-Danaf RN, Huberman AD, Niell CM. Diverse visual
features encoded in mouse lateral geniculate nucleus. J Neurosci 33:
4642– 4656, 2013.
Rivlin-Etzion M, Zhou K, Wei W, Elstrott J, Nguyen PL, Barres BA,
Huberman AD, Feller MB. Transgenic mice reveal unexpected diversity of
on-off direction-selective retinal ganglion cell subtypes and brain structures
involved in motion processing. J Neurosci 31: 8760 – 8769, 2011.
Rodieck RW, Watanabe M. Survey of the morphology of macaque retinal
ganglion cells that project to the pretectum, superior colliculus, and parvicellular laminae of the lateral geniculate nucleus. J Comp Neurol 338:
289 –303, 1993.
Sanes JR, Masland RH. The types of retinal ganglion cells: current status and
implications for neuronal classification. Annu Rev Neurosci 38: 221–246,
2015.
Schiller PH, Malpelli JG. Properties and tectal projections of monkey retinal
ganglion cells. J Neurophysiol 40: 428 – 445, 1977.
Schlamp CL, Montgomery AD, Mac Nair CE, Schuart C, Willmer DJ,
Nickells RW. Evaluation of the percentage of ganglion cells in the ganglion
cell layer of the rodent retina. Mol Vis 19: 1387–1396, 2013.
Schmidt TM, Chen SK, Hattar S. Intrinsically photosensitive retinal ganglion cells: many subtypes, diverse functions. Trends Neurosci 34: 572–580,
2011.
Sherry DM, Wang MM, Bates J, Frishman LJ. Expression of vesicular
glutamate transporter 1 in the mouse retina reveals temporal ordering in
development of rod vs. cone and ON vs. OFF circuits. J Comp Neurol 465:
480 – 498, 2003.
Siminoff R, Schwassmann HO, Kruger L. An electrophysiological study of
the visual projection to the superior colliculus of the rat. J Comp Neurol 127:
435– 444, 1966.
Simon DK, O’Leary DD. Development of topographic order in the mammalian retinocollicular projection. J Neurosci 12: 1212–1232, 1992.
Szucs A. Applications of the spike density function in analysis of neuronal
firing patterns. J Neurosci Methods 81: 159 –167, 1998.
Trenholm S, Johnson K, Li X, Smith RG, Awatramani GB. Parallel
mechanisms encode direction in the retina. Neuron 71: 683– 694, 2011.
Ugolini G. Advances in viral transneuronal tracing. J Neurosci Methods 194:
2–20, 2010.
Vaney DI, Peichl L, Wassle H, Illing RB. Almost all ganglion cells in the
rabbit retina project to the superior colliculus. Brain Res 212: 447– 453,
1981.
Vaney DI, Sivyer B, Taylor WR. Direction selectivity in the retina: symmetry
and asymmetry in structure and function. Nat Rev Neurosci 13: 194 –208,
2012.
van Wyk M, Taylor WR, Vaney DI. Local edge detectors: a substrate for fine
spatial vision at low temporal frequencies in rabbit retina. J Neurosci 26:
13250 –13263, 2006.
Vong L, Ye C, Yang Z, Choi B, Chua SJ, Lowell BB. Leptin action on
GABAergic neurons prevents obesity and reduces inhibitory tone to POMC
neurons. Neuron 71: 142–154, 2011.
Wickersham IR, Finke S, Conzelmann KK, Callaway EM. Retrograde
neuronal tracing with a deletion-mutant rabies virus. Nat Methods 4: 47– 49,
2007.
Yonehara K, Shintani T, Suzuki R, Sakuta H, Takeuchi Y, NakamuraYonehara K, Noda M. Expression of SPIG1 reveals development of a
retinal ganglion cell subtype projecting to the medial terminal nucleus in the
mouse. PLoS One 3: e1533, 2008.
Zhang Y, Kim IJ, Sanes JR, Meister M. The most numerous ganglion cell
type of the mouse retina is a selective feature detector. Proc Natl Acad Sci
USA 109: E2391–E2398, 2012.
Zhao X, Chen H, Liu X, Cang J. Orientation-selective responses in the
mouse lateral geniculate nucleus. J Neurosci 33: 12751–12763, 2013.
J Neurophysiol • doi:10.1152/jn.00227.2016 • www.jn.org
Downloaded from http://jn.physiology.org/ by 10.220.33.1 on June 17, 2017
Grubb MS, Thompson ID. Quantitative characterization of visual response
properties in the mouse dorsal lateral geniculate nucleus. J Neurophysiol 90:
3594 –3607, 2003.
Grubb MS, Thompson ID. Visual response properties of burst and tonic
firing in the mouse dorsal lateral geniculate nucleus. J Neurophysiol 93:
3224 –3247, 2005.
Huberman AD, Wei W, Elstrott J, Stafford BK, Feller MB, Barres BA.
Genetic identification of an on-off direction-selective retinal ganglion cell
subtype reveals a layer-specific subcortical map of posterior motion. Neuron
62: 327–334, 2009.
Humphrey NK. Responses to visual stimuli of units in the superior colliculus
of rats and monkeys. Exp Neurol 20: 312–340, 1968.
Jeon CJ, Strettoi E, Masland RH. The major cell populations of the mouse
retina. J Neurosci 18: 8936 – 8946, 1998.
Johnson J, Tian N, Caywood MS, Reimer RJ, Edwards RH, Copenhagen
DR. Vesicular neurotransmitter transporter expression in developing postnatal rodent retina: GABA and glycine precede glutamate. J Neurosci 23:
518 –529, 2003.
Kay JN, De la Huerta I, Kim IJ, Zhang Y, Yamagata M, Chu MW,
Meister M, Sanes JR. Retinal ganglion cells with distinct directional
preferences differ in molecular identity, structure, and central projections. J
Neurosci 31: 7753–7762, 2011.
Kim IJ, Zhang Y, Meister M, Sanes JR. Laminar restriction of retinal
ganglion cell dendrites and axons: subtype-specific developmental patterns
revealed with transgenic markers. J Neurosci 30: 1452–1462, 2010.
Land PW, Kyonka E, Shamalla-Hannah L. Vesicular glutamate transporters
in the lateral geniculate nucleus: expression of VGLUT2 by retinal terminals. Brain Res 996: 251–254, 2004.
Levick WR. Receptive fields and trigger features of ganglion cells in the visual
streak of the rabbits retina. J Physiol 188: 285–307, 1967.
Linden R, Perry VH. Massive retinotectal projection in rats. Brain Res 272:
145–149, 1983.
Livingstone M, Hubel D. Segregation of form, color, movement, and depth:
anatomy, physiology, and perception. Science 240: 740 –749, 1988.
Madisen L, Zwingman TA, Sunkin SM, Oh SW, Zariwala HA, Gu H, Ng
LL, Palmiter RD, Hawrylycz MJ, Jones AR, Lein ES, Zeng H. A robust
and high-throughput Cre reporting and characterization system for the whole
mouse brain. Nat Neurosci 13: 133–140, 2010.
Margolis DJ, Detwiler PB. Different mechanisms generate maintained activity in ON and OFF retinal ganglion cells. J Neurosci 27: 5994 – 6005, 2007.
Marshel JH, Garrett ME, Nauhaus I, Callaway EM. Functional specialization of seven mouse visual cortical areas. Neuron 72: 1040 –1054, 2011.
Marshel JH, Kaye AP, Nauhaus I, Callaway EM. Anterior-posterior direction opponency in the superficial mouse lateral geniculate nucleus. Neuron
76: 713–720, 2012.
Martin PR. The projection of different retinal ganglion cell classes to the
dorsal lateral geniculate nucleus in the hooded rat. Exp Brain Res 62: 77– 88,
1986.
Maunsell JH, Newsome WT. Visual processing in monkey extrastriate cortex.
Annu Rev Neurosci 10: 363– 401, 1987.
Merigan WH, Maunsell JH. How parallel are the primate visual pathways?
Annu Rev Neurosci 16: 369 – 402, 1993.
Mooney RD, Nikoletseas MM, Hess PR, Allen Z, Lewin AC, Rhoades RW.
The projection from the superficial to the deep layers of the superior
colliculus: an intracellular horseradish peroxidase injection study in the
hamster. J Neurosci 8: 1384 –1399, 1988.
Morin LP, Studholme KM. Retinofugal projections in the mouse. J Comp
Neurol 522: 3733–3753, 2014.
Murphy GJ, Rieke F. Network variability limits stimulus-evoked spike
timing precision in retinal ganglion cells. Neuron 52: 511–524, 2006.
Nover H, Anderson CH, DeAngelis GC. A logarithmic, scale-invariant
representation of speed in macaque middle temporal area accounts for speed
discrimination performance. J Neurosci 26: 10049 –10060, 2005.
Pang JJ, Gao F, Wu SM. Light-evoked excitatory and inhibitory synaptic
inputs to ON and OFF alpha ganglion cells in the mouse retina. J Neurosci
23: 6063– 6073, 2003.