Hidden Origins of Spontaneous Eye Movements in Albinism

Pendular nystagmus resembles the eye movements people make when looking outside while riding a moving train: the eyes automatically move along with the moving landscape and then spring back to the resting position. Nerve cells in a small brain area (known as the nucleus of the optic tract) selectively respond to this movement and become active. In healthy individuals, this activity leads to the tightening of the eye muscles to stabilize the image. However, in albinism, this process works a bit differently.

Jorrit Montijn, Valentina Rugiccini and their colleagues, under the supervision of Alexander Heimel, have now demonstrated in albino mice that the cells in this brain area are no longer selective for the direction of image movement.

Jorrit Montijn: “We show that the nucleus of the optic tract might be the source of the problem. Previous research already suggested that this area is involved in eye movements, but it could not be ruled out that (also) other areas, such as the cortex, cause pendular nystagmus. By simultaneously measuring both the cortex and the nucleus of the optic tract in the same mice, we were able to eliminate this question.”

“We now know that there is something wrong with this area, but we still don’t know what can be done about it. The next steps would be to translate this into practice. One possible option could be Deep Brain Stimulation of the area, but this still needs to be tested, and it is not known if it has an effect. Another option is perhaps surgery or even gene therapy in the future. It is now up to more clinically oriented scientists to investigate this.”

Reference :

1. Impaired Direction Selectivity in the Nucleus of the Optic Tract of Albino Mice – (https://iovs.arvojournals.org/article.aspx?articleid=2791377)

Source: Eurekalert