Pathological oscillations within and outside the basal ganglia can manifest in several ways. In PD, pathological oscillations are known to occur in the beta (11–30 Hz) frequency range (A) and have been recorded in several areas in the basal ganglia and even cortex. In dystonic patients, pathological oscillations mostly occur in the lower frequency range, especially theta (4–7 Hz). These oscillations have been recorded within the basal ganglia, including GPi, but also downstream in muscles during dystonic movements (B). Similarly, TS patients have increased activity in 2–7 Hz and in alpha (8–13 Hz) frequencies within the basal ganglia (C). In ET patients, oscillations within the thalamus and cortex have been coherent with peripheral tremor frequency (D). In most cases, pathological oscillations occur in low frequencies.