Neuroscience 2004 Abstract
| Presentation Number: | 839.15 |
|---|---|
| Abstract Title: | Development of the auditory to visual system connections in the brain of the postnatal ZRDCT/AN anophthalmic mouse. |
| Authors: |
Le Houillier, J.*1
; Miceli, D.2
; Bronchti, G.1
1Chimie-Biologie, UQTR, Trois-Rivieres, Canada 2Psychology, UQTR, Trois-Rivieres, Canada |
| Primary Theme and Topics |
Development - Development of Sensory and Limbic Systems -- Visual system |
| Secondary Theme and Topics | Sensory Systems<br />- Multisensory |
| Session: |
839. Visual System I Poster |
| Presentation Time: | Wednesday, October 27, 2004 10:00 AM-11:00 AM |
| Location: | San Diego Convention Center - Hall A-H, Board # E48 |
| Keywords: | crossmodal plasticity, DiI, neuronal tracer, blind |
Research has demonstrated that the blind human who lost vision early in his life uses his occipital cortex, normally visual, for auditory and somatosensory tasks (Leclerc et al., Neuroreport, 2000, 11-3:545; Sadato et al., Nature, 1996,380-6574 :526). Some degree of cross-modal plasticity has also been shown in blind rodents such as the mole rat (Bronchti et al., Eur.J.Neurosci., 2002, 16:311), the neonatally enucleated hamster (Izraeli et al., Eur.J.Neurosci., 2002,15:693) and the anophthalmic ZRDCT/An mouse (Robert et al., 33rd SFN, 2003, 266.3). In all these models, auditory inputs to the visual dorso-lateral geniculate nucleus (LGNd) in the thalamus originated from the inferior colliculus (IC). The aim of this study is to investigate when these ectopic connections between the auditory brainstem and the visual thalamus develop in the neonatal anophthalmic mouse. To achieve this, we used paraformaldehyde fixed brains of anophthalmic newborn mice aged from 5 to 12 days old where lipophilic fluorescent crystals (DiI) were inserted in the IC. The same was done on brains of eyed C57Bl/6 control mice. After a few weeks during which the neuronal tracer expanded and labeled the IC projections to the thalamus, the brains were cut on the frontal plane and sections (100µm width) were observed with the help of a fluorescent microscope and photographed. Our results show that IC projections to LGNd are visible in the anophthalmic mice only, at P8 and thereafter. In “eyed” 8 days old control mice, only “explorating” growth cones could be observed in the vicinity of LGNd and never later. These results suggest that the invasion of visual targets by auditory fibers in the anophthalmic mice is the consequence of the development of new synapses and not of the stabilization of aberrant connections as suggested in other blind animal models. Supported by grants from the NSERC of Canada (grant 239898) and from NATEQ.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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