The latest Journal of Neuroscience features a study on the neuroscience behind Akiyoshi Kitaoka’s famouse Rotating Snakes illusion and to celebrate they’re made a ‘Rotating Brain’ illusion for the front cover.
This type of illusion, often called a peripheral drift illusion, was thought to occur due to slow drifting eye movements but this new study suggests that it is more likely to be explained by rapid but tiny eye movements called saccades.
Brain-shaped version of Akiyoshi Kitaoka’s “Rotating Snakes” illusion. In its usual presentation, the image consists of concentric circles of stepwise luminance gradients with curved edges, which produces a strong illusion of rotation in most observers. New evidence suggests this illusion is produced by transient oculomotor events such as microsaccades, saccades, and blinks, rather than continuous drift.
Despite the fantastic cover I expect the journal to outdo itself next time and have both an article explaining the neuroscience Brocken spectre as well as an image you can hide up a mountanside to create 20 metre tall ghost-like figures.
Link to study (via
Mind Hacks 
You write, “…a strong illusion of rotation in most observers.”
So what does it mean if you don’t see any rotation at all?
I found that if I tracked across the image more or less randomly the snakes rotated. If I fixed my gaze on one of the black dots at the centre of a snake the rotation quickly stopped.