0000000000204448
AUTHOR
Konstantin Behrend
EFFERENT CONNECTIONS OF THE CEREBELLUM OF THE WEAKLY ELECTRIC FISH EIGENMANNIA SP. (GYMNOTODEI)
An efferent connection of lobus caudalis cells of the cerebellum of the electric fish Eigenmannia sp. has been verified by means of electrical stimulation and recording techniques. Stimulating in the lobus caudalis, an orthodromic activation has been found in the reticular formation of the midbrain tegmentum. Switching recording and stimulating electrodes led to an antidromic activation in cells of the lobus caudalis. The area identified in the midbrain corresponds to what, in higher vertebrates, is called the red nucleus.
Color- and motion-specific units in the tectum opticum of goldfish
Extracellular recordings were performed from 69 units at different depths between 50 and [Formula: see text]m below the surface of tectum opticum in goldfish. Using large field stimuli (86[Formula: see text] visual angle) of 21 colored HKS-papers we were able to record from 54 color-sensitive units. The colored papers were presented for 5[Formula: see text]s each. They were arranged in the sequence of the color circle in humans separated by gray of medium brightness. We found 22 units with best responses between orange, red and pink. About 12 of these red-sensitive units were of the opponent "red-ON/blue-green-OFF" type as found in retinal bipolar- and ganglion cells as well. Most of them w…
Temporal resolution and temporal transfer properties: gabaergic and cholinergic mechanisms.
Temporal resolution is a basic property of the visual system and critically depends upon retinal temporal coding properties which are also of importance for directional coding. Whether the temporal coding properties for directional coding derive form inherent properties or critically depend upon the temporal coding mechanisms is unclear. Here, the influence of acetylcholine and GABA upon photopic temporal coding was investigated in goldfish, using flicker stimuli, in a behavioral and an electrophysiological (ERG) approach. The goldfish temporal resolution ability decreased from more than 90% correct choices at 20 Hz flicker frequency to about 65% at 45 Hz flicker frequency with a flicker fu…