Spatial organization of the bipolar cell's receptive field in the retina of the tiger salamander.

Abstract

SUMMARY1. The spatial properties of rods, horizontal cells and bipolar cells were studied by intracellular recording in the isolated, perfused retina of the tiger salamander, Ambystoma tigrinum. Low stimulus intensities were used in order to keep cell responses close to, or within, their linear intensity/response range.2. Spatial properties of bipolar cell receptive fields, measured while perfusing with normal Ringer solution, were compared with those measured during exposure to agents that eliminated the bipolar cells' receptive field surround (RFS). In this way, the spatial properties of the receptive field centre (RFC) and those of the RFS could be characterized independently.3. To a good approximation, the contribution to the horizontal cell's response of unit area of its receptive field declined exponentially with distance from the centre of the receptive field. The (apparent) length constant describing this decay was 200 ,um. The one-dimensional length constant of the horizontal cell syncytium was thus 248 ,tm. The variation of response amplitude with the radius of a centred circular stimulus was consistent with this finding.4. This was true also of the RFCs of bipolar cells. The one-dimensional length constant of the RFC of off-centre bipolar cells averaged 124 ,um. That of the RFC of on-centre cells averaged 62 ,tm though values were more variable, the RFCs of some on-centre cells being comparable to those of off-centre cells. These values were independent of the class of photoreceptor driving the bipolar cell.5. The large size of the RFCs of off-centre cells and many on-centre cells cannot be explained by light scatter within the retina or by voltage spread within the rod syncytium. We proposed that off-centre cells are tightly coupled in a syncytium. Oncentre cells, on average, are less tightly coupled.6. The spatial properties of the bipolar cell's RFS were consistent with the notion that the RFS represents a convolution of the horizontal cell's receptive field and the bipolar cell's RFC.7. The spatial properties of bipolar cell receptive fields were reconstructed from the measured properties of their RFCs and the measured properties of horizontal cell receptive fields. Under the conditions of our experiments, the bipolar cell's response MS 7478 W. A. HARE AND W. G. OWEN could be described by a linear difference between a component generated by the RFC and a component generated by the RFS.8. The spatial filtering characteristics of the bipolar cells were calculated from our data. They show that, under the conditions of our experiments, bipolar cell receptive fields act as bandpass spatial filters tuned to an optimum spatial frequency of 0-8 mm-' (average for off-centre cells) and 1-02 mm-1 (average for off-centre cells).

The network behind spatio‐temporal patterns: building low‐complexity retinal models in CNN based on morphology, pharmacology and physiology

“…However, there are some inconsistencies with some previous recordings ( [28,29] from turtle and [30] from perch retinas) since this lateral inhibition cannot be found in spatial cone responses (see Figure 9) suggesting that the feedback does not or only slightly a ect the cone membrane potential. This observation also contradicts recordings from the salamander retina (horizontal cells, [23,25,31]). If the observation is accepted it generates a hypothesis that the feedback is likely to be of neuromodulatory type (similar networktheoretical deductions can be found in References [32,33] suggesting that the feedback shifts the calcium current activation threshold).…”

Feedback from Horizontal Cells to Rod Photoreceptors in Vertebrate Retina

“…(1) A major function of HC-to-cone feedback is the creation of center-surround receptive fields that enhance edge detection (Baylor et al, 1971). Consistent with such a function for horizontal cell-torod feedback, bipolar cells receptive fields in salamander retina exhibit center-surround antagonism under conditions in which synaptic input is provided entirely by rods (Hare and Owen, 1990). However, there is no evidence for centersurround receptive fields in mouse rod bipolar cells (Bloomfield and Xin, 2000).…”

The role of retinal bipolar cell in early vision: an implication with analogue networks and regularization theory

“…Recent physiological experiments done on lower vertebrates revealed the electrical coupling between bipolar cells (Kujiraoka and Saito 1986; Saito and Kujiraoka 1988;Hare and Owen 1990). This bipolar-bipolar coupling is not taken into account in the present paper, since it is still unclear if the bipolar-bipolar coupling is a general feature of the retina, including that of mammals.…”

“…If the direct input from the horizontal cell to the bipolar cell is assumed, the voltage distribution of the bipolar cell response, x, is expressed simply by a difference between the cone response and the horizontal cell response (Hare and Owen 1990), i.e.,…”

“…Accordingly, the spatial and temporal properties of cone and horizontal cell responses have been described by discrete linear network models (Lamb and Simon, 1976;Torre et al 1983;Yagi 1986;Ohshima et al 1995) from which the response properties are characterized in terms of underlying physiological mechanisms, e.g., membrane and gap-junctional conductances. A recent quantitative analysis demonstrated that the bipolar cell receptive field can be described by a linear difference between the profile of receptive field center and receptive field surround (Hare and Owen 1990). These observations suggest that the receptive field properties of the bipolar cell can be explained quantitatively by the linear analogue network.…”