The spatiotemporal transfer function of crayfish lamina monopolar neurons

Abstract

1. The graded, synaptic potentials of first-order visual interneurons (lamina monopolar cells) were examined with intracellular recordings. The spatiotemporal properties were characterized with drifting sine wave gratings and annuli. 2. Annulus-elicited inhibition is maximal for annulus-test pulse intervals of approximately 140 ms and declines exponentially. The inhibition declines with increasing annular internal radii (ri). 3. Grating responses were examined with respect to spatial and temporal frequency. The gratings elicit sinusoidal signals that are approximately linear with contrast. 4. Variations in spatial frequency produce response functions with a low-pass or modest band-pass characteristic, which are described by a difference of Gaussians sensitivity profile. The central Gaussian approximates the sensitivity profile of photoreceptors. The inhibitory Gaussian is similar to the inhibitory field estimated with annulus pulses. The peak of the inhibitory Gaussian is approximately 18% of the peak excitatory Gaussian. 5. Variations in temporal frequency generally produce transfer functions with a band-pass characteristic and a peak at 1.0 Hz. These data were described by a difference of exponentials function convolved with a low-pass filter that approximates the photoreceptor response. The inhibitory time course estimated from these data was similar to that of the annulus measurements. 6. The spatiotemporal properties of lateral inhibition are consistent with inhibitory action by the lamina amacrine neurons. The proposed model is spatiotemporally inseparable and nonrecurrent. 7. Eleven of 20 monopolar cells tested exhibited a strong orientation preference with a bias to the vertical. Photoreceptors exhibit little or no orientation preference.

Polarization sensitivity in crayfish lamina monopolar neurons

“…It should be noted however, that at low intensities the photoreceptor response does not exhibit distinct transient and plateau phases (Fig. 1B) and the same is true for most LMC neurons at intensities less than 10 times threshold (Glantz and Bartels 1994). Under these conditions therefore, if the mean intensity is within the linear range of the receptor, the voltage modulation should be related to the PS by Eq.…”

“…Crayfish Procambarus clarkii and Pacifasticus leniusculus of both sexes and 8 to 12 cm in length were prepared as in Kirk et al (1982) and Glantz and Bartels (1994). The chelipeds and rostrum were removed and the eyestalks were cemented to the cephalic carapace with cyanoacrylate adhesive.…”

“…2C, broken line) with an exponent of 1.9 (compared to 1.0 for photoreceptors). Previous studies (Wang-Bennett and Glantz 1987;Glantz and Bartels 1994) have shown that the response-intensity functions of crayfish LMCs are heterogeneous and appear to depend upon the particular LMC (M1-M4). The larger LMCs (M2-M4) yield steeper functions (n ~ 2) which may reflect a higher density of synaptic terminals from the receptors (N/issel and Waterman 1977;Strausfeld and N~issel 1981).…”

Polarization sensitivity in the red swamp crayfish Procambarus clarkii enhances the detection of moving transparent objects

“…P. clarkii are sensitive to moving visual stimuli over a velocity range of at least four orders of magnitude (Glantz, 2001), indicating that motion detection is a critical component of the crayfish visual system. A significant portion of the primary visual synapse (Glantz and Bartels, 1994) and the ascending optic tract (Wiersma and Yamaguchi, 1966) are devoted to motion sensitivity. Glantz (Glantz, 2001) proposed that the polarization sensitive-neurons might also contribute to this pathway.…”

Neuronal processing of translational optic flow in the visual system of the shore crabCarcinus maenas

“…In order to make intracellular recordings from visual interneurones in the optic lobe it was necessary to exchange the blood for oxygenated Ringer's solution. This was done by a method broadly similar to that described for crayfish (Kirk et al, 1982;Glantz and Bartels, 1994). The hypodermis dorsal to the heart was exposed by making a circular cut (ca.…”