Neuroscience 2005 Abstract
| Presentation Number: | 25.14 |
|---|---|
| Abstract Title: | Endogenous Otx2 transfer into visual cortex specifies critical period plasticity. |
| Authors: |
Sugiyama, S.*1
; Dupas, S.2
; Volovitch, M.2
; Prochiantz, A.2
; Hensch, T. K.1
1Neuronal Circuit Development, RIKEN BSI, Wako-shi, Japan 2France, Hirosawa 2-1, 351-0198, |
| Primary Theme and Topics |
Development - Synaptogenesis and Activity-Dependent Development -- Synaptogenesis and activity-dependent plasticity |
| Secondary Theme and Topics | Development<br />- Development of Sensory and Limbic Systems<br />-- Visual system |
| Session: |
25. Activity-Dependent Development: Molecular Signals Poster |
| Presentation Time: | Saturday, November 12, 2005 2:00 PM-3:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # B7 |
| Keywords: | GABA, ocular dominance, parvalbumin, homeoprotein |
Neuronal responsiveness to input from the two eyes is established in the visual cortex through an activity-dependent competition during early postnatal life. We previously identified the importance of cortical GABA circuits for critical period (CP) induction, in particular the development of parvalbumin (PV)-positive cells (Hensch, Annu Rev Neurosci. 2004). Maturation of these interneurons and hence critical period timing is specified by the experience-dependent uptake of a homeodomain transcription factor, Otx2 (Sugiyama et al., US SFN Abstr 155.10, 2004). Interestingly, Otx2 transcripts are not detected in visual cortex but are expressed in the retina and LGN. Consistent with a trans-cellular transfer of homeoproteins, intraocular injection of biotinylated-Otx2 is distributed along the visual pathway and specifically transported into PV-cells in visual cortex. Here, to confirm the role of endogenous Otx2, we infused an inhibitory antibody (to block trans-cellular transfer) or penetratin-coupled siRNA (to inhibit Otx2 synthesis) into the visual cortex or retina. The anti-Otx2 antibody infusion of visual cortex (osmotic minipump from >P20) reduced Otx2 accumulation into PV-cells, as did intraocular injection from pre-CP ages (<P20). Similar intraocular siRNA treatment also decreased cortical Otx2 in PV-cells. In all cases, cortical Otx2 reduction kept PV expression immaturely weak. Extracellular recording of single-units from the binocular zone revealed little or no ocular dominance plasticity with monocular eyelid suture at CP ages for all of these treatments. In contrast, CP plasticity was not affected by cortical siRNA or any control infusions. Taken together, endogenous Otx2 transfer into visual cortex may establish the cortical milieu for CP plasticity by regulating specific GABA-cell maturation.
Supported by HFSP, Ministry of Education, Culture, Sports, Science, and Technology, Japan, and RIKEN BSI
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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