Friday, November 10, 2006
Proof now established of the direct computation of optical flow fields between two hemispheres in the visual centre of flies:
For the first time, scientists at the Max Planck Institute for Neurobiology in Martinsried near Munich have been able to show how two nerve cells communicate with each other from different hemispheres in the visual centre. This astoundingly simple circuit diagram could at a later date provide a model for algorithms to be deployed in technical systems.
Movements in space create in humans and animals so-called optical flow fields which are characteristic for the movement in question. In a forward movement, the objects flow by laterally, objects at the front increase in size and objects further away hardly change at all. At a higher level in the visual centre in the brain, there must be a computation of the visual information, so that animals can differentiate between their own movement and movement of their environment and are able to correct their course if necessary. It is important for the analysis of flow fields that the movement information from both eyes is merged so that the whole flow field can be assessed. In their current study, Karl Farrow, Jürgen Haag and Alexander Borst have for the first time proved the direct link between two nerve cells, one in each half of the brain, combining the movement signals from both the facetted eyes of a fly.
Continued at "Two Nerve Cells in Direct Contact (Max Planck Institute)"
Based on the journal Nature Neuroscience paper "Nonlinear, binocular interactions underlying flow field selectivity of a motion-sensitive neuron" (Abstract - Full text is currently available but this may change).
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