Abstract
The nucleus isthmi is a prominent part of the frog's visual system. Each nucleus isthmi receives input from the ipsilateral tectum and sends output to both tecta. Until now, no non-tectal inputs to the nucleus isthmi of amphibians have been demonstrated. Anterograde and retrograde tracing with horseradish peroxidase in Rana pipiens and Acris crepitans now reveal that a diffuse group of cells in the mesencephalic tegmentum projects to the caudal region of the contralateral nucleus isthmi. These cells are primarily within the nucleus anterodorsalis tegmenti. This same group of tegmental cells may also project to the caudal region of the ipsilateral nucleus isthmi. A similar investigation of the brain of another frog, Xenopus laevis, has not revealed any evidence of this tegmento-isthmic projection.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
