Modelling the development of retinal mosaics

Stephen Eglen, Arjen van Ooyen and David Willshaw.

For papers related to this project, please visit my publications page.

Here are some movies that show our model at various stages during development. Movies are provided in MPEG and animated GIF format. The animated GIF pictures can be viewed within your browser, whereas you will need a suitable program for viewing the MPEG files (e.g. mpeg_play for Unix, Media Player on the PC). Frames are taken approximately every 70 seconds of simulated time.

(Once an animated GIF has been downloaded, it will loop repeatedly until you leave that page.)

Normal development

MPEG 1 (42 frames, 0.6MB) or GIF 1 (0.2MB): Example of normal development (100 cells). Development is rapid during first few frames, so please single-step through the movie.

Each circle represents the dendritic field of one cell. In the first stage, dendrites primarily extend, and there is little cell movement. Once neighbouring dendrites overlap, the cells begin to move away from other. Eventually this combination of cell movement and dendrite extension/retraction produces a regular arrangement of neurons. (Neurons at the border of the network are much larger than the other neurons due to boundary conditions.)

Lesioning cells

MPEG 2 (100 frames, 1.3MB) or GIF 2 (0.5 MB): After a network has developed, 10 central cells are removed from the network (at frame 46). The neighbouring cells then move into this vacated area to cover up the `hole in visual space'. (In the GIF version there is a slight pause at the frame when the lesion is made.)

Adding cells

MPEG 3 (84 frames, 1.2MB) or GIF 3 (0.5 MB): Again a network of 100 cells is developed as normal, and then 100 extra cells added at random positions (at frame 44). (In the GIF version there is a slight pause at the frame when the new cells are added.)

MPEG 4 (150 frames, 2.0MB) or GIF 4 (0.8 MB): This time the network starts with 70 cells, which then increases to 140 cells (frame 60) and then to 210 cells (frame 120).

Fixed size simulations

Some more recent work, not described in the first paper, shows how the model can use just cell movement to make mosaics. See the next page for more details.

Last modified: Wed Jun 19 22:28:26 BST 2002