Premium
Neurophysiology of spastic , a behavior mutant of the mexican axolotl: Altered vestibular projection to cerebellar auricle and area acoustico‐lateralis
Author(s) -
Ide Charles F.
Publication year - 1977
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901760305
Subject(s) - biology , vestibular system , hindbrain , neuroscience , cerebellum , anatomy , phenocopy , climbing fiber , mutant , central nervous system , cerebellar cortex , genetics , gene
The spastic mutant of Ambystoma mexicanum shows deficiencies in swimming coordination and equilibrium. Behavior “phenocopy” experiments done previously indicated that vestibular projections to cerebellum and hindbrain interneurons might be responsible for mutant behavior patterns. To test function in mutant vestibular projections, single unit recordings were carried out in the vestibulo‐cerebellum (auricle) and hindbrain area acousticolateralis (AAL) of wild‐type and mutant animals in response to natural vestibular stimulation. Vestibular unit types responding during longitudinal tilting or to sustained tilt were encountered in equal proportions in both animal types. However, mutants showed a significant increase in spontaneously active units in these areas indicating possible deficiencies in inhibitory circuitry. In addition, the topographic location of vestibular units changed under the influence of the spastic gene. In mutants, significant numbers of units were found “translocated” into a ventro‐caudal auricular zone abutting the AAL. Anatomical studies detailed in the following paper have shown this same area to contain grossly “translocated” cerebellar cells and afferent fiber tracts in mutants. These data are drawn together in a model in which deficiencies in the (form and) inhibitory function of the vestibulo‐cerebellum is postulated to underly the behavioral abnormalities of the spastic phenotype.