Document Detail

Neural substrate for motor control of feeding in amphibians.
MedLine Citation:
PMID:  9973634     Owner:  NLM     Status:  MEDLINE    
Descending pathways to premotor/motor centers and their cell groups of origin were studied by means of retrograde biocytin tracing experiments in the frog Discoglossus pictus and the plethodontid salamander Plethodon jordani, which differ remarkably in the structure and function of their feeding apparatus and their feeding strategy. Labeled neurons were found in 30 major cell groups located in the telencephalon, diencephalon, synencephalon, mesencephalon and rhombencephalon. The number and distribution of nuclei are very similar in both species. Furthermore, the descending pathways of these groups of neurons take the same courses inside the medulla oblongata. Axons of most nuclei descend either in the ventromedial or ventrolateral medulla oblongata, and it is concluded that the spatial arrangement of pathways is identical in the species studied. Bilateral electrical stimulation of the optic tectum of the plethodontid salamander Hydromantes italicus elicited strong discharges of short latencies in the hypoglossal nerve. In most hypoglossal motor neurons, excitatory postsynaptic potentials (EPSPs) of short latencies followed paired shocks applied at intervals as short as 3 ms, but showed temporal and spatial facilitation, suggesting that the EPSPs include mono- as well as polysynaptic components. In the ventral white matter, orthodromic single units were found that are candidates for excitatory reticular interneurons. These properties of tectal descending pathways in salamanders strongly differ from those found in toads. Differences in feeding behavior and its control by the premotor/motor networks between the species investigated do not appear to result from anatomically altered input or from a different organization of descending pathways to these premotor/motor centers, but rather from differences in local properties of reticular premotor networks as well as from different effects of neuromodulatory systems.
U Dicke; G Roth; T Matsushima
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta anatomica     Volume:  163     ISSN:  0001-5180     ISO Abbreviation:  Acta Anat (Basel)     Publication Date:  1998  
Date Detail:
Created Date:  1999-04-01     Completed Date:  1999-04-01     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370272     Medline TA:  Acta Anat (Basel)     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  127-43     Citation Subset:  IM    
Brain Research Institute, University of Bremen, Germany.
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MeSH Terms
Anura / anatomy & histology*,  physiology*
Brain / anatomy & histology,  physiology
Bufo bufo / anatomy & histology,  physiology
Efferent Pathways / anatomy & histology,  physiology
Electric Stimulation
Excitatory Postsynaptic Potentials / physiology
Feeding Behavior / physiology*
Hypoglossal Nerve / physiology
Lysine / analogs & derivatives,  diagnostic use
Medulla Oblongata / anatomy & histology,  physiology
Motor Cortex / anatomy & histology*,  physiology*
Species Specificity
Superior Colliculi / physiology
Urodela / anatomy & histology*,  physiology*
Reg. No./Substance:
56-87-1/Lysine; 576-19-2/biocytin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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