The Centromedian-parafascicular Complex
The CM-Pf complex is part of the caudal intralaminar nuclei of the thalamus and has a critical role on arousal, sensory awareness, pain control, behavior and cognition. The CM nucleus is associated with the sensorimotor striatum, whereas the Pf nucleus with the limbic and associative striatum. The CM-Pf complex has important reciprocal connections with the basal ganglia and undergoes partial neurodegeneration in PD. In the hemi-parkinsonian rat, high-frequency stimulation of the CM-Pf complex had an anti-akinetic effect in the off-levodopa condition, whereas it had an anti-dyskinetic effect in the on-levodopa condition. Some clinical data in humans have also pointed out its possible role in dyskinesias.[64–66] Indeed, the stimulation of this region for pain control showed by serendipity to also improve involuntary movements. In some PD patients with thalamic stimulation, an improvement of tremor and dyskinesias was observed. Postoperative MRIs showed that the control of both tremor and dyskinesia was associated with a more posterior and deeper position of the electrodes, corresponding to the CM-Pf complex.
More recently, a multi-target strategy with double STN or GPi and CM-Pf stimulation has been experimented in few PD patients.[69,70] CM-Pf stimulation could improve tremor and dyskinesias, although slightly less than GPi. Moreover, CM-Pf stimulation might slightly reduce bradykinesia and rigidity, but less than STN or GPi stimulation.
Further studies are necessary to support these preliminary observations.
Expert Rev Neurother. 2013;13(12):1319-1328. © 2013 Expert Reviews Ltd.