We recorded from the spiking on-off unit in the first optic chiasm (between lamina and medulla) in the blowfly Calliphora vicina, and investigated its spatial properties. The receptive field extends over (11.4+/-0.9)-degrees horizontally and (8.7+/-0.6)-degrees vertically, i.e. about 7 by 5 interommatidial angles. The line spread function of the on-off unit - calculated from its response to moving sinusoidal gratings - has a half-width of (2.3+/-0.2)-degrees. This half-width is slightly broader than that of the photoreceptor. Lateral inhibition occurs when two different areas of the receptive field are stimulated simultaneously. Fast temporal adaptation (i.e. adaptation to trains of short light pulses) takes place independently in different areas of the receptive field.
|Number of pages||5|
|Journal||Journal of comparative physiology a-Sensory neural and behavioral physiology|
|Publication status||Published - May-1993|
- ON-OFF UNIT
- SPATIAL PROCESSING
- GANGLION CELL
- TRANSIENT CELLS