Abstract
Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3336-3349 |
| Number of pages | 14 |
| Journal | Journal of Neuroscience |
| Volume | 36 |
| Issue number | 11 |
| DOIs | |
| State | Published - Mar 16 2016 |
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Keywords
- Electrophysiology
- Neural circuit
- NMDA receptors
- Receptive field
- Retinal ganglion cell
- Synaptic transmission
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Synaptic mechanisms generating orientation selectivity in the on pathway of the rabbit retina. / Venkataramani, Sowmya; Taylor, William.
In: Journal of Neuroscience, Vol. 36, No. 11, 16.03.2016, p. 3336-3349.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Synaptic mechanisms generating orientation selectivity in the on pathway of the rabbit retina
AU - Venkataramani, Sowmya
AU - Taylor, William
PY - 2016/3/16
Y1 - 2016/3/16
N2 - Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input.
AB - Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input.
KW - Electrophysiology
KW - Neural circuit
KW - NMDA receptors
KW - Receptive field
KW - Retinal ganglion cell
KW - Synaptic transmission
UR - http://www.scopus.com/inward/record.url?scp=84961262990&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84961262990&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.1432-15.2016
DO - 10.1523/JNEUROSCI.1432-15.2016
M3 - Article
C2 - 26985041
AN - SCOPUS:84961262990
VL - 36
SP - 3336
EP - 3349
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 11
ER -