SciELO - Scientific Electronic Library Online

vol.41 issue4The anteromedial extrastriate complex is critical for the use of allocentric visual cues and in the retention of the Lashley III maze task in ratsPlasticity in primary somatosensory cortex resulting from environmentally enriched stimulation and sensory discrimination training author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links

  • On index processCited by Google
  • Have no similar articlesSimilars in SciELO
  • On index processSimilars in Google


Biological Research

Print version ISSN 0716-9760


OLAVARRIA, JAIME F; LAING, ROBYN; HIROI, RYOKO  and  LASIENE, JÚRATE. Topography and axon arbor architecture in the visual callosal pathway: effects of deafferentation and blockade of TV-methyl-D-aspartate receptors. Biol. Res. [online]. 2008, vol.41, n.4, pp.413-424. ISSN 0716-9760.

Visual callosal fibers link cortical loci in opposite hemispheres that represent the same visual field but whose locations are not mirror-symmetric with respect to the brain midline. Presence of the eyes from postnatal day 4 (P4) to P6 is required for this map to be specified. We tested the hypothesis that specification of the callosal map requires the activation of A'-methyl-D-aspartate receptors (NMDARs). Our results show that blockade of NMDARs with MK-801 during this critical period did not induce obvious abnormalities in callosal connectivity patterns, suggesting that retinal influences do not opérate through NMDAR-mediated processes to specify normal callosal topography. In contrast, we found that interfering with NMDAR function either through MK801-induced blockade of NMDARs starting at P6 or neonatal enucleation significantly increases the length of axon branches and total length of arbors, without major effects on the number of branch tips. Our results further suggest that NMDARs act by altering the initial elaboration of arbors rather than by inhibiting a later-occurring remodeling process. Since the callosal map is present by P6, just as axonal branches of simple architecture grow into gray matter, we suggest that regulation of arbor development by NMDAR-mediated processes is important for maintaining the precisión of this map.

Keywords : corpus callosum; interhemispheric commissure; map; NMDAR; striate cortex.

        · text in English     · English ( pdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License