{'fraction_non_alphanumeric': 0.03871829105473965, 'fraction_numerical': 0.012016021361815754, 'mean_word_length': 5.125340599455041, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Neuromodulation: Anatomical Precision Is Neither Tedious Nor Outdated

The recently published paper The Deep Brain Stimulation of the Pedunculopontine Tegmental Nucleus (PPN alias PPTg) (1) refers to our work on anatomical localization of this structure (2). The authors state that the conclusions of our study “were not sustained by any direct . . . neurophysiologic validation.” We would maintain that anatomical localization is best confirmed through the use of an anatomical method and that, in living subjects, the noninvasive gold standard is direct localization through MRI. Indeed, instances are on record where, in functional neurosurgery, “neurophysiologic validation” resulted in the inaccurate anatomical localization of intended structures that are much larger in volume and much more commonly targeted than the PPN (3–5). By definition, the PPN extends from caudal mesencephalon to rostral pons (6,7). However, the authors take issue that our study “seemed to extend the PPN into the mesencephalon rather than in the pons.” Moreover, they state that, with their targeting techniques, “Neuroimaging showed that the electrode contacts were always correctly placed below the ponto-mesencephalic line” (1). Yet, Mazzone et al. present an axial MRI documenting electrode location at the level of the decussating superior cerebellar peduncles in the caudal mesencephalon (fig. 5, panel #1) (1). We also note that their illustration shows one electrode artifact to lie within, the other lateral to, the hypointensity of the lemniscal system. Again by definition, the PPN is located medial to the lemniscal tracts. For comparison, Figure 1 is an axial MRI of one of our own patients with an anatomically well-placed PPN electrode at the level of the caudal mesencephalon. The discrepancy of electrode location vis-à-vis accepted PPN anatomy in the report by Mazzone et al. as well as in other similar studies (1,8,9) has been raised elsewhere (10–12). We believe that the literature demonstrates that this discrepancy is not simply “an error . . . in the illustration” (13,14). The scientific and neurosurgical communities might consider taking this into account when reflecting on the results discussed in associated publications (8,15,16).