Sub-Regional Motor-Somatosensory Connectivity and Lifespan Plasticity in Functional Networks
Adnan A S Alahmadi1,2,3
1Radiologic Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.
Neurosciences (Riyadh, Saudi Arabia)
|July 8, 2026
Summary
Healthy aging shifts brain connectivity from segregated sensorimotor processing to diffuse global connections. This study reveals age-related changes in motor and somatosensory cortex networks, highlighting neuroplasticity.
Area of Science:
- Neuroscience
- Aging Research
- Brain Connectivity
Background:
- The aging brain undergoes significant functional and structural changes.
- Understanding alterations in functional connectivity within specific brain regions is crucial for aging research.
- The primary motor cortex, somatosensory cortex, and supplementary motor area play key roles in motor control and sensory processing.
Purpose of the Study:
- To investigate how cytoarchitectonically defined subdivisions of the primary motor cortex, somatosensory cortex, and supplementary motor area (SMA) reorganize their integration with large-scale brain networks during healthy aging.
- To examine the lifespan trajectories of functional connectivity within these specific motor and somatosensory subregions.
Main Methods:
- Cross-sectional analysis of resting-state fMRI data from 150 healthy individuals (aged 23-80).
- Utilized the Jülich Brain Atlas to define seed regions in M1, premotor cortex, PSC, and SMA.
- Calculated functional coupling between seed regions and canonical large-scale networks (DMN, salience, dorsal attention, frontoparietal).
Main Results:
- Older adults showed a significant loss of network segregation compared to younger adults.
- Younger adults exhibited strong sensorimotor integration with negative default mode network (DMN) coupling.
- Older adults displayed widespread, diffuse positive connectivity across the DMN and frontoparietal networks, with middle-aged participants showing a transitional profile.
Conclusions:
- Aging is associated with a shift from segregated sensorimotor processing to a more dedifferentiated, globally connected brain architecture.
- Analysis of specific cytoarchitectonic subdivisions is important for detecting subtle compensatory neuroplasticity mechanisms during aging.
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