Carol A. Mason, PhD

Carol A. Mason, PhD

Research Interest

In our studies of axon guidance in the visual pathways, we analyze the behaviors, cellular interactions and molecular directives of retinal axon growth cones during avoidance and crossing of the midline at the optic chiasm. This system is a model for axon navigation at the CNS midline, and for patterning the binocular projection. We have identified a molecular program of transcription factors and guidance receptors that regulate cell identity and projection of the ipsilateral retinal axon pathway through the optic chiasm. Current work aims to investigate transcriptional regulators and guidance mechanisms for the contralateral projection, and mechanisms of growth cone interactions with cells of the chiasm midline.

We have recently addressed whether the programs of gene expression that direct retinal axon decussation at the optic chiasm are relevant to the formation of connections of retinal axons in their first target, the lateral geniculate nucleus. We now aim to identify molecular regulators of axon-targeting and retinal ganglion cell axon arbor morphogenesis, and to analyze the interplay of molecular factors and neural activity in the targeting and refinement of eye-specific projections.

A genetic model for these studies is the albino. In both humans and rodents, lack of pigment in the eye leads to visual impairment due to the misrouting of retinal fibers at the optic chiasm to contralateral rather than ipsilateral targets. Albinism is caused by diverse genes controlling melanogenesis. We aim to study how factors in the melanogenic pathway from the retinal pigment epithelium (RPE) affect retinal patterning, and retinal ganglion cell specification and projection fate.

  • Mason, C.A., Kuwajima, T., and Wang, Q.  (2014) The development of retinal decussations, IN: The Visual Neurosciences, Eds. L.M. Chalupa and J.S. Werner, MIT Press, Cambridge, MA (in press).
  • Kuwajima, T., Sitko, A.A., Bhansali, P., Jurgens, C., Guido, W., and Mason, C. (2013)  ClearT: a detergent- and solvent-free clearing method for neuronal and non-neuronal tissue. Development 140:1364-8. doi: 10.1242/dev.091844.
  • Roffler-Tarlov, S., Liu, J.H., Naumova, E.N., Bernal-Ayala, M.M., and Mason, C.A. (2013) L-Dopa and the albino riddle: content of L-Dopa in the developing retina of pigmented and albino mice. PLoS One. 2013;8(3):e57184. doi: 10.1371/journal.pone.0057184. Epub 2013 Mar 19.
  • Kuwijama T, Yoshida Y, Takehara N, A, Petros TJ, Kumanogoh, Jessell TM, Sakurai, T and Mason C  Optic chiasm presentation of Semaphorin6D in the context of Plexin-A1 and Nr-CAM promotes retinal axon midline crossing. Neuron 74: 676–690, May 24, 2012-13.
  • Rebsam, A., Bhansali, P, and Mason, C.A. (2012) Eye-specific projections of retinogeniculate axons are altered in albino mice J. Neurosci. 32: 4821-4826.
  • Petros, T., Shresta, B., and Mason, C.A. (2009) Specificity and sufficiency of EphB1 in driving the ipsilateral retinal projection, J. Neurosci. 29: 3463-3474.
  • Petros, T.J., Rebsam, A., and Mason, C. (2008). Retinal axon growth at the optic chiasm: To cross or not to cross. Annu Rev Neurosci 31, 295-315.

For a complete list of publications, please visit

  • Bystander Intervention Training, January 2024 (Columbia Sexual Violence Response Office)