Attachment problem

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Under the bond issue (Engl. "Binding problem") refers to the question of the neural basis of sensory integration , ie the ability of the brain , from a variety of sensations uniform perceptions to construct.

Structures are known in the visual system that are more strongly activated by certain shapes, colors or movements in their receptive field than when other patterns are shown. This property of some neurons is the basis of the idea that the sensory information is broken down into such "basic components" and later put together again. If one sees, for example, a red ball moving from left to right, then, according to this idea and roughly simplified, different neurons signal "something red", "something round" and "a movement from left to right".

The attachment problem now poses the - still largely unresolved - question of how these signals are "linked" to the overall impression of a moving red ball. The name goes back to perceptual psychological experiments, among others in the laboratory of Anne Treisman , in which it could be shown that under certain conditions and in the absence of attention , wrong connections can occur and, for example, objects can be perceived in the wrong colors.

One theory of this is that synchronous oscillations of the neuron groups involved are responsible for bringing this information together at the neuronal level. In the above example, this would imply that neurons for "something red", "something round" and "a movement from left to right" would be rhythmically active at equal time intervals. Experimental measurements gave partly contradicting results. It is also unclear here which time intervals are considered "synchronous", what is considered to be oscillation, and whether or not synchronous activity selectively activates neurons in later processing stages. It should also be noted that there are neurons in some brain regions that respond more strongly to complex stimulations than to isolated properties such as color and movement.

In connection with the rise in recent years, interest in neuroscientific theories of consciousness mainly from the was theorist Christoph von der Malsburg developed hypothesis of binding by synchronous oscillation among others, Wolf Singer , Andreas K. Engel , Francis Crick and Christof Koch represented . The latter two, however, later distanced themselves from the idea of ​​possibly being able to adequately explain awareness of experiences with the help of this theory.

However, a clear definition of the term “binding” has not yet been found. While it was originally limited to intramodal integration (i.e. unification within one sense as in the example above), it has been increasingly expanded over time and is now mostly used for intermodal integration (merging of the senses into a uniform perception).

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