Orienting system
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The orienting system describes a system whereby reflexive and more controlled eye movements are initiated as part of the attentional response. The orienting system involves the superior colliculus, magno cells in the pulvinar (thalamus) and the secondary and tertiary areas of the extrastriate cortex e.g. V5. The orienting system follows the second 'geniculate' pathway. This pathway projects first to the superior colliculus and then to the pulvinar of the thalamus before projecting mainly to the posteria parietal area, but there are also projections that fan out to points along the V1 and V4 pathway.
La Berge provides a model that describes the complex interaction between the superior colliculus and other brain areas. Broadly, a functional pattern can be discern which describes a number of layers within the superior colliculus. The superficial or upper layers are involved in passing sensory information at high speeds to be analysed for location of the a target, which is passed on to the cortex. This movement-sensitive system is important.
[edit] References
- David Andrews, "From theory to practice."