ILLUSORY ARM EXTENSION

The term illusory arm extension refers to a subclass of the "motor illusions, which is itself a subclass of the group of "illusory movement experiences. The phenomenon of illusory arm extension can be induced by means of vibratory stimulation of the biceps tendon of a bent and immobilized arm in a blindfolded test person. This procedure typically produces a tonic vibration reflex, followed by an illusory feeling of movement around the elbow, followed by the " kinaesthetic illusion of extending the lower arm into extracorporeal space. A variant of the illusory arm extension is known as "Pinocchio illusion. The mediation of both types of motor illusion is attributed to the interplay between basic sensorimotor impulses (involving patterns of alpha and gamma motoneuron activity, muscle spindle discharge level, and the resulting movements of the arm), and higher cognitive and affective processes as represented by parietal brain areas involved with bodily representations and/or representations of movement. The illusory arm extension may also be classified as a vibration-induced "phantom illusion or as a "body schema illusion.

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