Sensitivity and dynamics of rod signals in H1 horizontal cells of the macaque monkey retina.

Abstract

We measured the sensitivity, temporal frequency response, latency, and receptive field diameter of rod input to the H1 horizontal cell type in an in vitro preparation of the macaque retina. The H1 cell has both a cone-connected dendritic tree and a long axon-like process that terminates in a rod-connected arbor. We recorded from the H1 cell body where rod signals were distinguished by sensitivity to short wavelength light after dark adaptation. Receptive fields of rod vs. cone mediated responses were coextensive, indicating that the rod signal is transmitted via rod-cone gap junctions. Sensitivity of the H1 cell rod signal was approximately 1 log unit higher than that of the cone signal. Below cone threshold rod signals were temporally low-pass, with a cutoff frequency below 10 Hz. Rod signals became faster and more transient with increasing light levels. We conclude that the H1 cell rod signal is not sensitive in the low scotopic range and, by comparison with the rod signal recorded directly in cones (Schneeweis & Schnapf (1995) Science, 268, 1053-1056), signal transmission across the cone-H1 synapse does not significantly filter the temporal properties of the rod signal.

A simple and inexpensive light source for research in visual neuroscience

“…For instance, changes in the amplitude of PII and PIII components of the ERG recorded from the rat (Fig. 4A) are in general agreement with the higher light sensitivity of rod-bipolars compared to rods, because of a large collecting area (see Berntson and Taylor, 2000;Verweij et al, 1999). Although the light energy provided by 1 ms flash is not sufficient to evoke a saturated a-wave (PIII component), this may be achieved by using multiple LEDs.…”

“…This in turn prevents the application of harmonic analysis (Campbell and Robson, 1968), because linearity in the response to light of visually responsive neurons generally holds over a limited portion of the intensity-response range. The use of sinusoidal light stimuli in studies investigating the processing of temporal information at the cellular level may help defining the correspondence between processing steps and specific cell types (Lankheet et al, 1991;Verweij et al, 1999). On the other hand, the use of bulky cathode ray tubes (CRT) for generating sinusoidal light stimuli in cellular work is unpractical.…”

Rod and Cone Contributions to Horizontal Cell Light Responses in the Mouse Retina

“…Rod signals in horizontal cells can be determined by the light response waveform of the horizontal cell, because the temporal properties of the rod response are not significantly filtered by signal transmission from photoreceptor to horizontal cell (Verweij et al, 1999). Because rod and cone signals cannot be easily dissected in the mouse retina using stimuli of different wavelengths, we took an alternative approach, using transgenic mouse lines: cone signals were assessed using the rhodopsin knock-out mouse, which is a model for pure cone function (Humphries et al, 1997; Jaissle et al, 2001); rod inputs were isolated in the CNGA3 knock-out mouse, which lacks cone function (Biel et al, 1999).…”

L and M Cone Contributions to the Midget and Parasol Ganglion Cell Receptive Fields of Macaque Monkey Retina

“…The temporal frequency of stimulus modulation was chosen to maximize our ability to measure L and M cone inputs free from contamination by rod input, because our calculations of the L and M cone contrasts produced by our three-LED visual stimulator are not valid if the rod system is responding to stimuli. Although our mean light level of 1000 trolands was high enough to reduce rod system response, we also took advantage of the sluggish response of the rod system by making most of our measurements at 9.7 Hz, a temporal frequency that we had previously determined to be high enough to further attenuate any remaining rod responses (Verweij et al, 1999). For testing the validity of our assumption that this frequency was not high enough to reduce opponency by weakening center surround antagonism, some measurements were also made at temporal frequencies ranging from 1.2 to 19.5 Hz.…”