The brain consists of approximately 100 billion nerve cells (so-called neurons); each neuron is connected to approximately 1,000 other neurons. The result is a giant network with billions of connection routes that are used to convey messages and information through the brain to control our entire organism. Like a computer, neurons form switching circuits, whereby different switching circuits have different tasks. For instance, some switching circuits are for storing information, whilst others are responsible for processing signals. Neurons communicate with each other via electrical signals – that is why brain activity can be examined by measuring brain waves (EEG = electroencephalography) or the electrical fields produced by the brain (MEG = magnetoencephalography).
In principle, neurons that belong to the same switching circuit can "fire" simultaneously or asynchronously. This differs depending on the process or activity. There are certain diseases where the asynchronous nerve cell assemblies of a switching circuit suddenly start to synchronise: the neurons are permanently and excessively engaged in synchronous activity and they all fire at the same time. It is this pathologically synchronised "firing" that causes the typical symptoms – the tremor of Parkinson's and the phantom sound of tinnitus.
Unfortunately, some neurological diseases are accompanied by the sudden occurrence of pathologically "enhanced" synchronous activity of a nerve cell assembly that is the start of a vicious circle:
The brain's natural synaptic plasticity causes the pathologically synchronous neurons to strengthen their connections
The stronger the network between the cells, the better the synchronous alignment!
The result is the occurrence of defective processes in the brain that lead to the formation of highly synchronous neuronal networks with pathologically enhanced connections. The brain has learned "pathological firing".