Document Detail


Telencephalic connections in the Pacific hagfish (Eptatretus stouti), with special reference to the thalamopallial system.
MedLine Citation:
PMID:  9603376     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The pallium of hagfishes (myxinoids) is unique: It consists of a superficial "cortical" mantle of gray matter which is subdivided into several layers and fields, but it is not clear whether or how these subdivisions can be compared to those of other craniates, i.e., lampreys and gnathostomes. The pallium of hagfishes receives extensive secondary olfactory projections (Wicht and Northcutt [1993] J. Comp. Neurol. 337:529-542), but there are no experimental data on its nonolfactory connections. We therefore investigated the pallial and dorsal thalamic connections of the Pacific hagfish. Injections of tracers into the pallium labeled many cells bilaterally in the olfactory bulbs. Other pallial afferents arise from the contralateral pallium, the dorsal thalamic nuclei, the preoptic region, and the posterior tubercular nuclei. Descending pallial efferents reach the preoptic region, the dorsal thalamus, and the mesencephalic tectum but not the motor or premotor centers of the brainstem. Injections of tracers into the dorsal thalamus confirmed the presence of reciprocal thalamopallial connections. In addition, these injections revealed that there is no "preferred" pallial target for the ascending thalamic fibers; instead, ascending thalamic and secondary olfactory projections overlap throughout the pallium. The mesencephalic tectum and tegmentum, which receive afferents from a variety of sensory sources, are interconnected with the dorsal thalamus; thus, ascending nonolfactory sensory information may reach myxinoid pallia via a tectal-thalamic-telencephalic route. A comparative analysis of pallial organization reveals that the subdivisions of the pallium in gnathostomes (i.e., medial, dorsal, and lateral pallia) cannot be recognized with certainty in hagfishes.
Authors:
H Wicht; R G Northcutt
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of comparative neurology     Volume:  395     ISSN:  0021-9967     ISO Abbreviation:  J. Comp. Neurol.     Publication Date:  1998 Jun 
Date Detail:
Created Date:  1998-07-07     Completed Date:  1998-07-07     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0406041     Medline TA:  J Comp Neurol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  245-60     Citation Subset:  IM    
Affiliation:
Klinikum der Johann Wolfgang Goethe-Universität, Dr. Senckenbergische Anatomie, Institut für Anatomie II (Experimentelle Neurobiologie), Frankfurt, Federal Republic of Germany. wicht@em.uni-frankfurt.de
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MeSH Terms
Descriptor/Qualifier:
Animals
Carbocyanines
Diencephalon / anatomy & histology,  physiology
Fluorescent Dyes
Functional Laterality / physiology
Hagfishes / physiology*
Histocytochemistry
Mesencephalon / anatomy & histology,  physiology
Neostriatum / anatomy & histology,  physiology
Neural Pathways / anatomy & histology,  physiology
Prosencephalon / anatomy & histology,  physiology
Telencephalon / anatomy & histology,  physiology*
Thalamus / anatomy & histology,  physiology*
Grant Support
ID/Acronym/Agency:
DC01081/DC/NIDCD NIH HHS; NS24699/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Carbocyanines; 0/Fluorescent Dyes; 40957-95-7/3,3'-dioctadecylindocarbocyanine

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


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