Visual Neuroscience

Brief Communication

Phr1 is required for proper retinocollicular targeting of nasal–dorsal retinal ganglion cells

BRADLY Q. VOa1, A. JOSEPH BLOOMa2 and SUSAN M. CULICANa1 c1

a1 Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri

a2 Department of Psychiatry, Washington University School of Medicine, Saint Louis, Missouri

Abstract

Precise targeting of retinal projections is required for the normal development of topographic maps in the mammalian primary visual system. During development, retinal axons project to and occupy topographically appropriate positions in the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC). Phr1 retinal mutant mice, which display mislocalization of the ipsilateral retinogeniculate projection independent of activity and ephrin-A signaling, were found to have a more global disruption of topographic specificity of retinofugal inputs. The retinocollicular projection lacks local refinement of terminal zones and multiple ectopic termination zones originate from the dorsal–nasal (DN) retinal quadrant. Similarly, in the dLGN, the inputs originating from the contralateral DN retina are poorly refined in the Phr1 mutant. These results show that Phr1 is an essential regulator of retinal ganglion cell projection during both dLGN and SC topographic map development.

(Received April 21 2010)

(Accepted October 19 2010)

(Online publication February 16 2011)

Correspondence:

c1 Address correspondence and reprint requests to: Dr. Susan M. Culican, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 South Euclid Avenue, Ophthalmology Box 8096, Saint Louis, MO 63110. E-mail: culican@vision.wustl.edu