Functional anatomy of the pallidal base in Parkinson's disease

Jamal M. Taha, Jacques Favre, Thomas K. Baumann, Kim Burchiel

Research output: Contribution to journalArticle

16 Scopus citations


OBJECTIVE: The purpose of this study is to define the morphology of the boundary between the globus pallidus and the ansa lenticularis (i.e., pallidal base) in humans. This information is important for surgeons who perform pallidotomy. METHODS: Thirty-eight patients with Parkinson's disease underwent pallidotomy using microrecording techniques. The pallidal base was identified by the loss of neuronal single unit activity and by the change in background noise, as analyzed on the audio monitor and by fast Fourier transformation. RESULTS: Three quarters of the patients had an abrupt transition of the background noise from neuronal to axonal activity. One quarter of the patients had multiple successive transitions of the background activity, over a distance of 0.4 to 2 mm (median, 1 mm). CONCLUSION: We conclude that the pallidal base is not a smooth, sharp boundary between the globus pallidus and the ansa lenticularis. We propose two models that define the morphology of the pallidal base. One model depicts the pallidal base as a multifolded boundary that distinctly separates pallidal neurons from ansa lenticularis axons. Another model depicts the pallidal base as an indistinct transitional boundary between the globus pallidus and the ansa lenticularis, which contains axonal fibers intermixed with small clusters of pallidal neurons. We discuss the clinical relevance of these findings.

Original languageEnglish (US)
Pages (from-to)1164-1168
Number of pages5
Issue number6
Publication statusPublished - Dec 1996



  • Ansa lenticularis
  • Globus pallidus
  • Pallidotomy
  • Parkinson

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery

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