scholarly journals Receptive field center-surround interactions mediate context-dependent spatial contrast encoding in the retina

2018 ◽  
Author(s):  
Maxwell H. Turner ◽  
Gregory W. Schwartz ◽  
Fred Rieke
Keyword(s):  
Receptive Field ◽  
Spatial Structure ◽  
Ganglion Cell ◽  
Sensory Processing ◽  
Visual Information ◽  
Retinal Ganglion ◽  
Natural Stimuli ◽  
The Impact ◽  
Receptive Field Center

SummaryAntagonistic receptive field surrounds are a near-universal property of early sensory processing. A key assumption in many models for retinal ganglion cell encoding is that receptive field surrounds are added only to the fully formed center signal. But anatomical and functional observations indicate that surrounds are added before the summation of signals across receptive field subunits that creates the center. Here, we show that this receptive field architecture has an important consequence for spatial contrast encoding: the surround can control sensitivity to fine spatial structure by changing the way the center integrates visual information over space. The impact of the surround is particularly prominent when center and surround signals are correlated, as they are in natural stimuli. This role of the surround differs substantially from classic center-surround models and raises the possibility that the surround plays unappreciated roles in shaping ganglion cell sensitivity to natural inputs.

scholarly journals Receptive field center-surround interactions mediate context-dependent spatial contrast encoding in the retina

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Maxwell H Turner ◽  
Gregory W Schwartz ◽  
Fred Rieke
Keyword(s):  
Receptive Field ◽  
Spatial Structure ◽  
Ganglion Cell ◽  
Sensory Processing ◽  
Visual Information ◽  
Macaque Monkey ◽  
Retinal Ganglion ◽  
Natural Stimuli ◽  
The Impact ◽  
Receptive Field Center

Antagonistic receptive field surrounds are a near-universal property of early sensory processing. A key assumption in many models for retinal ganglion cell encoding is that receptive field surrounds are added only to the fully formed center signal. But anatomical and functional observations indicate that surrounds are added before the summation of signals across receptive field subunits that creates the center. Here, we show that this receptive field architecture has an important consequence for spatial contrast encoding in the macaque monkey retina: the surround can control sensitivity to fine spatial structure by changing the way the center integrates visual information over space. The impact of the surround is particularly prominent when center and surround signals are correlated, as they are in natural stimuli. This effect of the surround differs substantially from classic center-surround models and raises the possibility that the surround plays unappreciated roles in shaping ganglion cell sensitivity to natural inputs.

Interaction between center and surround in rabbit retinal ganglion cells

1995 ◽  
Vol 73 (4) ◽  
pp. 1547-1567 ◽  
Author(s):  
D. K. Merwine ◽  
F. R. Amthor ◽  
N. M. Grzywacz
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Ganglion Cells ◽  
Inhibitory Effect ◽  
Sine Wave ◽  
Retinal Ganglion ◽  
Field Center ◽  
Response Versus ◽  
Receptive Field Center ◽  
Stimulation Of

1. The interaction between the center and surround mechanisms of a variety of rabbit retinal ganglion cell classes was examined in extracellular single-unit recordings in an isolated eyecup preparation. Ganglion cell classes studied included on and off brisk sustained and transient, on and off sluggish sustained and transient, on-off and on directionally selective, orientationally selective, and large field units. The surround effects observed were qualitatively similar in all these ganglion cell classes. 2. The average response-versus-contrast functions for stimuli within the ganglion cells' receptive-field centers were relatively linear between threshold and saturation for all ganglion cell classes examined. The major effect of surround stimulation on the center response-versus-contrast function was a reduction in the slope of the linear portion of the curve, rather than a downward, parallel shift of the function. Stimulation of the surround had no systematically significant effect on the contrast threshold for the center spot, and, when it did have a significant effect, it sometimes decreased, rather than increased the magnitude of threshold. 3. Step changes in surround contrast were most effective when they were made simultaneously with step changes in the center; surround inhibition decreased significantly when it preceded stimulation of the center by > 100 ms and was generally ineffective when preceding the center by > 500 ms. The decrease in the inhibitory effect of surround stimulation was a monotonic function of delay between 0 and 500 ms. 4. Stimulation of the surround by step changes in the contrast of a sine-wave grating annulus produced qualitatively similar results to those obtained for pure luminance modulations. This suggests that the surround mechanism observed in these experiments was not due to pure luminance adaptation within the surround. The inhibitory effect of sine-wave gratings in the surround decreased monotonically as a function of spatial frequency. 5. Stimulation with a spot and an annulus that were both entirely within the ganglion cell's excitatory receptive-field center typically yielded nonadditive summation at contrasts whose linear sum of responses were below saturation. The effect of an annulus within the receptive-field center on responses elicited by a central spot quantitatively resembled the inhibition elicited from annuli in the inhibitory surround, after the excitatory center response due to the annulus was taken into account. These results suggest that the inhibiton elicited from the surrounds of the ganglion cells in these experiments extended into their receptive-field centers.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Interphotoreceptor coupling: an evolutionary perspective

2021 ◽  
Author(s):  
Lorenzo Cangiano ◽  
Sabrina Asteriti
Keyword(s):  
Visual Information ◽  
Signal To Noise Ratio ◽  
Electrical Coupling ◽  
Physiological Role ◽  
Cellular Processes ◽  
Contact Points ◽  
Highly Sensitive ◽  
The Many ◽  
The Impact

AbstractIn the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.

scholarly journals Spatial receptive field properties of rat retinal ganglion cells

2011 ◽  
Vol 28 (5) ◽  
pp. 403-417 ◽  
Author(s):  
WALTER F. HEINE ◽  
CHRISTOPHER L. PASSAGLIA
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Cell Types ◽  
Quantitative Information ◽  
Retinal Ganglion ◽  
X And Y Cells ◽  
Y Cells

AbstractThe rat is a popular animal model for vision research, yet there is little quantitative information about the physiological properties of the cells that provide its brain with visual input, the retinal ganglion cells. It is not clear whether rats even possess the full complement of ganglion cell types found in other mammals. Since such information is important for evaluating rodent models of visual disease and elucidating the function of homologous and heterologous cells in different animals, we recorded from rat ganglion cells in vivo and systematically measured their spatial receptive field (RF) properties using spot, annulus, and grating patterns. Most of the recorded cells bore likeness to cat X and Y cells, exhibiting brisk responses, center-surround RFs, and linear or nonlinear spatial summation. The others resembled various types of mammalian W cell, including local-edge-detector cells, suppressed-by-contrast cells, and an unusual type with an ON–OFF surround. They generally exhibited sluggish responses, larger RFs, and lower responsiveness. The peak responsivity of brisk-nonlinear (Y-type) cells was around twice that of brisk-linear (X-type) cells and several fold that of sluggish cells. The RF size of brisk-linear and brisk-nonlinear cells was indistinguishable, with average center and surround diameters of 5.6 ± 1.3 and 26.4 ± 11.3 deg, respectively. In contrast, the center diameter of recorded sluggish cells averaged 12.8 ± 7.9 deg. The homogeneous RF size of rat brisk cells is unlike that of cat X and Y cells, and its implication regarding the putative roles of these two ganglion cell types in visual signaling is discussed.

scholarly journals «War and Peace» of Ukrainian Tourism: the Impact of Geopolitical Factors on the Tourism Process in Ukraine

2019 ◽  
Author(s):  
Anatoliy Parfinenko
Keyword(s):  
Spatial Structure ◽  
Public Diplomacy ◽  
International Tourism ◽  
International Tourist ◽  
Tourist Flows ◽  
The World ◽  
Domestic Tourism ◽  
The Impact ◽  
Tourist Flow

The article intends to highlight geopolitical aspects in the development of international tourism in Ukraine as a global phenomenon that carries out economic, social and international political action. The paper analyzes international tourist flows in Ukraine, their dynamics and spatial structure during 2000–2017 in particular, in the context of military-political aggression on the part of Russia and intensification of Ukrainian-Russian intergovernmental relations. It has been established that the current dynamics of the international tourist flow in Ukraine is characterized by a sharp decrease in the volume of international visitors, a decrease in the rates of development of tourism activity and the reformatting of the spatial structure of the inbound and outbound tourist flow. The question arises as to the expediency of tourism development during the military-political confrontation. The experience of holding Eurovision–2017 in Ukraine, which took place against the backdrop of the anti-terrorist operation, is highlighted. The conclusion is drawn about the constructive role of tourism as a factor of «soft power» that can influence the informing of the world about the «Ukrainian issue». In this sense, international tourist flows acted as channels of public diplomacy, reflecting the true situation in Ukraine, which is fundamentally different from the Russian mass media. Attention is drawn to the intensification of domestic tourism in Ukraine, taking place against the backdrop of deteriorating key indicators of economic and social development. It is argued that the growth of the weight of domestic tourism was also possible due to the growth of patriotic sentiment in Ukrainian society. In a sense, the development of domestic tourism is seen as a continuation of the struggle of the Ukrainian people for their independence and territorial integrity. Consequently, the constructive role of tourism lies not only in the presentation of the country to the world community, but also in the construction of a national identity within the country. In this way domestic tourism favors further development of the Ukrainian political nation. Key words: international tourism; actors of geopolitical influence; Russia–Ukraine international relations; regional structure of tourism flows in Ukraine; public diplomacy.

Sign in / Sign up

Export Citation Format

Share Document