Intracellular recording and morphology of tectal neurons activated by contralateral nucleus isthmi in toads

1997 ◽  
Vol 42 (19) ◽  
pp. 1647-1651 ◽  
Author(s):  
Shurong Wang ◽  
Gangyi Wu
Keyword(s):  
Intracellular Recording ◽  
Nucleus Isthmi ◽  
Tectal Neurons

Dual actions of isthmic input to tectal neurons in a reptile, Gekko gekko

1999 ◽  
Vol 16 (5) ◽  
pp. 889-893 ◽  
Author(s):  
STEPHEN A. GEORGE ◽  
GANG-YI WU ◽  
WEN-CHANG LI ◽  
SHU-RONG WANG
Keyword(s):  
Electrical Stimulation ◽  
Optic Nerve ◽  
Optic Tectum ◽  
Nucleus Isthmi ◽  
Postsynaptic Potentials ◽  
Tectal Neurons ◽  
Electrical Connections ◽  
Stimulation Of

We analyzed postsynaptic potentials and dye-labeled morphology of tectal neurons responding to electrical stimulation of the optic nerve and of the nucleus isthmi in a reptile, Gekko gekko, in order to compare with previously reported interactions between the optic tectum and the nucleus isthmi in amphibians and birds. The results indicate that isthmic stimulation exerts inhibitory and excitatory actions on tectal cells, similar to dual isthmotectal actions in amphibians. It appears that dual actions of the isthmotectal pathway in amphibians and reptiles are shared by two subdivisions of the nucleus isthmi in birds. The morphology of tectal cells responding to isthmic stimulation is generally similar to that of tectoisthmic projecting neurons, but they differ particularly in that some tectoisthmic cells bear numerous varicosities whereas cells receiving isthmic afferents do not. Thus, it is likely that at least some tectoisthmic cells may not be in the population of tectal cells that can be affected by isthmic stimulation. Forty-four percent of injections resulted in dye-coupled labeling, suggesting extensive electrical connections between tectal cells in reptiles.

Postsynaptic potentials and morphology of tectal cells responding to electrical stimulation of the bullfrog nucleus isthmi

1990 ◽  
Vol 5 (5) ◽  
pp. 479-488 ◽  
Author(s):  
S.R. Wang ◽  
N. Matsumoto
Keyword(s):  
Electrical Stimulation ◽  
Rana Catesbeiana ◽  
Lucifer Yellow ◽  
Optic Tract ◽  
Nucleus Isthmi ◽  
Postsynaptic Potentials ◽  
Tectal Neurons ◽  
Synaptic Mechanisms ◽  
Stimulation Of ◽  
In Cells

AbstractPostsynaptic responses of tectal cells in the bullfrog (Rana catesbeiana) were intracellularly recorded following electrical stimulation of the optic tract and the nucleus isthmi, and fluorescent dye, Lucifer yellow, was injected into some of the impaled cells to show their morphologies. Two main response types were found: The first type was an EPSP followed by an IPSP, and the second type was single IPSP. The first type predominates in cells responding to the optic tract stimulation and the second type prevails in cells responding to the isthmic stimulation. Fifteen cells stained with Lucifer yellow were localized in layer 6 (11 cells), layer 7 (1 cell), and layer 8 (3 cells). They were mainly identified as pear-shaped cells, large ganglionic cells, and stellate cells. Three injections demonstrated “dye-coupling,” which labeled up to six cells following one injection. Comparisons of postsynaptic potentials with cellular morphologies suggested that the nucleus isthmi could directly excite large ganglionic neurons in layer 6. Synaptic mechanisms for strong isthmic inhibition on the tectal neurons remain unknown.

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