This is achieved by nerve stimulation. However, disrupting the synchronous rhythm the nerve cells have learned and achieving an "unlearning" affect takes more than simply firing off nerve stimuli at will; the stimulating signals are rather transmitted to the affected area of the brain as a clocked CR^® signal that is adapted to the specific circumstances of each patient on the basis of a physico-mathematical algorithm. Signals are applied either electrically via electrodes (Parkinsons´s) or sensory (e.g. acoustically) via the T30 CR^® neurostimulator for tinnitus (3,4,5).

The CR^® signal: clock with pause

To put it simply, one could describe the CR^® signal as an alternation between active stimulation (by means of clocked impulses) and specific signal interruptions. Active stimulation forces synchronous nerve cells to form sub-groups, each of which has its own new rhythm. When stimulation is interrupted the nerve cells in the sub-groups break free from the new forced rhythm and start to reorganise themselves with the intention of finding their way back to their original synchronous rhythm. As this takes place without a master nerve cell, the nerve cells' attempt to reorganise themselves quickly results in chaos: the nerve cells become desynchronised and stop working together in pathological synchrony (3).

Continuously repeating the processes of desynchronisation causes the nerve cells to unlearn step by step how to engage in hyperactivity and synchrony: as the nerve cells are repeatedly liberated from their synchronous state, the pathologically strengthened connections between nerve cells dismantle piece by piece driven by the brain´s natural plasticity, causing the nerve cells to unlearn step by step how to engage in compulsive synchronous behaviour (4,5).

Unlearning – an active process

Whilst the process of unlearning requires that nerve cells are forced out of their synchronous rhythm time and again by applying CR^® signals, it is equally important that nerve cell activity is not suppressed: this is because only active nerve cells are able to react to their environment and learn or unlearn. If, on the other hand, one were to inhibit nerve cell activity – as is the case with the so-called "lateral inhibition" induced by tinnitus noisers or maskers, for instance – then no learning effects would be achieved (4,6).


^{1 L. Roberts, J. Eggermont, D. Caspary, S. Shore, J. Melcher, J. Kaltenbach: Ringing Ears: The Neuroscience of Tinnitus; J Neurosci.; 30(45): 14972–14979 (2010)
2 H. Bergman and G. Deuschl: Pathophysiology of Parkinson’s disease: from clinical neurology to basic neuroscience and back; Mov. Disorders 17 S28–40 (2002)
3 P. A. Tass: A model of desynchronizing deep brain stimulation with a demand-controlled coordinated reset of neural subpopulations; Biol. Cybern. 89, 81-88 (2003)
4 P. A. Tass and M. Majtanik: Long-term anti-kindling effects of desynchronizing brain stimulation: a theoretical study; Biol. Cybern. 94, 58-66 (2006)
5 P. A. Tass: Verlernen krankhafter Synchronisation mittels desynchronisierender Hirnstimulation; Neurobiologie der Psychotherapie (2010)
6 C. Hauptmann and P.A. Tass: Cumulative and after-effects of short and weak coordinated reset stimulation: a modeling study. J. Neural Eng. 6 016004 (2009)}