A Cortical Parcellation Based Analysis of Ventral Premotor Area Connectivity

ABSTRACT

Introduction. The ventral premotor area (VPM) plays a crucial role in executing various aspects of motor control. These include hand reaching, joint coordination, and direction of movement in space. While many studies discuss the VPM and its relationship to the rest of the motor network, there is minimal literature examining the connectivity of the VPM outside of the motor network. Using region-based fMRI studies, we built a neuroanatomical model to account for these extra-motor connections.

Methods. Thirty region-based fMRI studies were used to generate an activation likelihood estimation (ALE) using BrainMap software. Cortical parcellations overlapping the ALE were used to construct a preliminary model of the VPM connections outside the motor network. Diffusion spectrum imaging (DSI)-based fiber tractography was performed to determine the connectivity between cortical parcellations in both hemispheres, and a laterality index (LI) was calculated with resultant tract volumes. The resulting connections were described using the cortical parcellation scheme developed by the Human Connectome Project (HCP).

Results. Four cortical regions were found to comprise the VPM. These four regions included 6v, 4, 3b, and 3a. Across mapped brains, these areas showed consistent interconnections between each other. Additionally, ipsilateral connections to the primary motor cortex, supplementary motor area, and dorsal premotor cortex were demonstrated. Inter-hemispheric asymmetries were identified, especially with areas 1, 55b, and MI connecting to the ipsilateral VPM regions.

Conclusion. We describe a preliminary cortical model for the underlying connectivity of the ventral premotor area. Future studies should further characterize the neuroanatomic underpinnings of this network for neurosurgical applications.

KEYWORDS:

• Connectomics
• ventral premotor
• VPM
• tractography
• parcellation

Acknowledgments

Data was provided [in part] by the Human Connectome Project, WU-Minn Consortium (Principle Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657) funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by the McDonnell Center for Systems Neuroscience at Washington University.

Disclosure statement

Dr. Michael Sughrue is the Chief Medical Officer of Omniscient Neurotechnologies. No products directly related to this were discussed in this paper. The other authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Additional information

Funding

This study did not receive any funding to be completed.

Notes on contributors

John R. Sheets

John R. Sheets is an anesthesiology resident at the University of Oklahoma Health Sciences Center in Oklahoma, USA.

Robert G. Briggs

Robert G. Briggs is a neurosurgeon working at the University of Oklahoma Health Sciences Center in Oklahoma, USA.

Nicholas B. Dadario

Nicholas B. Dadario is a medical student pursuing a Doctor of Medicine degree at Rutgers Robert Wood Johnson Medical School in New Jersey, USA.

Isabella M. Young

Isabella M. Young is a research associate at Cingulum Health in Sydney, Australia.

Michael Y. Bai

Michael Y. Bai is a student research assistant at Prince of Wales Private Hospital in Sydney, Australia.

Anujan Poologaindran

Anujan Poologaindran is a neuroscience PhD student in the Brain Mapping Unit at the University of Cambridge and The Alan Turing Institute in the United Kingdom.

Cordell M. Baker

Cordell M. Baker is a neurosurgical resident at the University of Utah School of Medicine.

Andrew K. Conner

Andrew K. Conner is a neurosurgeon working at the University of California, San Francisco in California, USA.

Michael E. Sughrue

Michael E. Sughrue is a neurosurgeon at the Prince of Wales Private Hospital and co-founder and Chief Medical Officer at Omniscient Neurotechnology, Sydney, Australia.