The effect of mean luminance on the size selectivity of identified target interneurons in the dragonfly |
| |
Authors: | Robert M Olberg Robert B Pinter |
| |
Institution: | 1. Department of Biological Sciences, Union College, 12308, Schenectady, NY, USA 3. Departments of Electrical Engineering and Zoology, University of Washington, 98195, Seattle, WA, USA
|
| |
Abstract: | 1. |
By penetrating axons in the ventral nerve cord of the dragonfly, Aeshna umbrosa, we measured the intracellular responses of target-selective visual interneurons to movement of black square targets ranging from 1° to 32° visual angle at several levels of mean background luminance.
| 2. |
Neuronal responses, measured both in number of spikes and in the magnitude of integrated postsynaptic potentials, showed a preference for larger target size at lower mean luminance (Table 1, Figs. 1–3). The latency of postsynaptic potential (psp) and spike responses from onset of target movement increased with a decrease in mean luminance (Fig. 1).
| 3. |
A measure of mean target size preference (Eqn. 1) for one identified interneuron (MDT4) in both laboratory and outdoor lighting shows a continuous decrease of preferred size with increases of mean luminance over more than 4 orders of magnitude.
| 4. |
The time to reach the new steady state of cell response after the decrease of mean luminance was ordinarily less than 30 s, but sometimes longer (Fig. 4).
|
|
| |
Keywords: | Mean luminance Size selectivity Interneurons Dragonfly Aeshna umbrosa |
本文献已被 SpringerLink 等数据库收录! |
|