Document Detail


Evolution of spontaneous activity in the developing rat superior colliculus.
MedLine Citation:
PMID:  8748987     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
During the first 10 days after birth in the rat there are a succession of major developmental stages in the retinotectal pathway. During most of this time, the only recordable event in the superior colliculus is spontaneous activity. We studied and characterized this spontaneous activity, hypothesizing that it could play an important role in pathway development. The spontaneous discharges are detectable on postnatal day 5 (P5). After P5, the number of spontaneously active cells per penetration increases up to P10, after which they decrease to adult-like levels by P14-P15. Between P5 and P10, the spontaneous discharges exhibit several patterns of activity, from constant firing to intermittent bursts with periods of quiescence, without any bearing to age. We isolated the retina and superior colliculus by injecting xylocaine onto the optic nerve and found no change in collicular activity. While this suggests that the spontaneous activity in the colliculus is independent of the retina at the ages studied, the opposite experiment, i.e., electrically stimulating the optic nerve, resulted in increased firing by collicular neurons, perhaps via nonclassical synaptic transmission. Finally, we compared interval histograms for spontaneously active cells between P5 and P15. The histograms suggest that at certain ages, spontaneous firing is more regular; moreover, these ages precede major functional advances, e.g., onset of numerous spontaneously firing cells at P6, the first response to optic nerve stimulation at P10, and the first light-evoked response at P12-P13. Our results support the hypothesis that spontaneous activity in the neonatal superior colliculus has a role in development of the retinotectal pathway, but the data also indicate that classical synaptic transmission is not involved.
Authors:
S K Itaya; S Fortin; S Molotchnikoff
Related Documents :
14725627 - Kv1 currents mediate a gradient of principal neuron excitability across the tonotopic a...
8221147 - Convergence of gastric and hepatic information in brain stem neurons of the rat.
6623937 - The statistical reliability of signals in single neurons in cat and monkey visual cortex.
171977 - Limbic neuronal firing rates in man during administration of nitrous oxide--oxygen or s...
18085597 - Lead exposure during development results in increased neurofilament phosphorylation, ne...
3013377 - The vestibulothalamic connections in the rat: a morphological analysis using wheat germ...
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  73     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1995 Sep 
Date Detail:
Created Date:  1996-10-24     Completed Date:  1996-10-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  1372-7     Citation Subset:  IM    
Affiliation:
Department of Biomedical Sciences, University of South Alabama, Mobile 36688, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Suckling
Optic Nerve / physiology*
Rats
Superior Colliculi / growth & development*,  physiology*
Visual Pathways / growth & development*

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


Previous Document:  Development and plasticity of the neural circuitry underlying visual recognition memory.
Next Document:  Physiological studies of visual cortex reorganization following cortical deafferentation in neonatal...