Reply: The cuneiform nucleus may be involved in the regulation of skeletal muscle tone by motor pathway: a virally mediated trans-synaptic tracing study in surgically sympathectomized mice

Sir, We appreciate the opportunity to respond to the comment by Xiang et al. (2013) on our review on interspecies differences in the pedunculopontine nucleus area. As exemplified by the data of Xiang et al. (2013) it is evident that the mesencephalic locomotor region compromises several distinct structures that are involved in initiation and inhibition of gait, and certainly the implications of both the cuneiform nucleus and the subcuneiform nucleus need to be studied in more detail. Also, as mentioned in our review, there is a paucity of data on the downstream mechanisms mediating neuronal activity in the mesencephalic locomotor region.The role of the pedunculopontine nucleus area as a target site for deep brain stimulation for treatment of medically refractory gait and postural abnormalities in late stage Parkinson’s disease and progressive supranuclear palsy still needs further clarification. Because post-mortem studies in Parkinson’s disease and progressive supranuclear palsy show ∼60% loss of cholinergic neurons in the pedunculopontine nucleus (Jellinger, 1988) it should also …