The structure of the diencephalic prepacemaker nucleus revisited: light microscopic and ultrastructural studies.

The prepacemaker nucleus (PPn), a bilateral cluster of neurons at the boundary of diencephalon and mesencephalon, controls frequency modulations of the electric organ discharge in weakly electric knifefish (Eigenmannia sp.). Previous light microscopic studies employing retrograde labelling with horseradish peroxidase suggested that the PPn is restricted to… CONTINUE READING