Related Experiment Video
Updated: May 19, 2026
09:52
Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Mapping different intra-hemispheric parietal-motor networks using twin Coil TMS
Anke Ninija Karabanov1, Chi-Chao Chao, Rainer Paine
1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. ankenk@drcmr.dk
Brain Stimulation
|September 4, 2012
Summary
This study reveals distinct parietal-motor connections. Inhibitory connections between the inferior-parietal lobule (IPL) and motor cortex exist in both hemispheres, but facilitatory connections are asymmetric, impacting motor control.
Area of Science:
- Neuroscience
- Motor Control
- Brain Connectivity
Background:
- Evidence suggests differing connectivity between anterior/posterior inferior-parietal lobule (IPL) and frontal motor areas.
- Understanding these parietal-motor networks is crucial for explaining functional specializations.
Purpose of the Study:
- Investigate distinct intra-hemispheric parietal-motor interactions along the IPL's anterior-posterior axis.
- Examine resting-state brain activity in human subjects.
Main Methods:
- Utilized twin-coil transcranial magnetic stimulation (TMS).
- Tested interactions between three IPL sites (anterior, central, posterior) and ipsilateral primary motor cortex (M1).
- Assessed effects at rest in both brain hemispheres.
Main Results:
- Anterior IPL stimulation inhibited ipsilateral M1 in both hemispheres.
- Central and posterior IPL stimulation facilitated ipsilateral M1 in the left hemisphere only.
- Significant inter-subject variability in optimal stimulation sites was observed.
Conclusions:
- The IPL exhibits asymmetric inhibitory and facilitatory connections to the ipsilateral M1.
- These asymmetric parietal-motor networks may underlie functional differences in reaching/grasping and motor system asymmetry.
- Future TMS studies should consider localized 'hot-spot' identification for the parietal cortex due to variability.
