Related Experiment Video
Updated: May 17, 2026
09:52
Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Hand dominance and age have interactive effects on motor cortical representations
Jessica A Bernard1, Rachael D Seidler
1Department of Psychology, University of Michigan, Ann Arbor, Michigan, USA. jessbern@umich.edu
Plos One
|October 11, 2012
Summary
Older adults show distinct motor cortex activity and handedness compared to younger adults. Age impacts how hand dominance influences brain activity and coordination.
Area of Science:
- Neuroscience
- Motor Control
- Aging Research
Background:
- Older adults display greater bilateral motor cortical activity during unimanual tasks than young adults.
- This bilateral activity resembles young adults with reduced hand dominance, yet older adults report stronger dominance.
- This creates ambiguity regarding how handedness manifests in the aging motor cortex.
Purpose of the Study:
- To investigate age-related differences in the interplay between handedness, motor cortical organization, and interhemispheric communication speed.
- To test the hypothesis of age-related shifts in interhemispheric interactions influencing these relationships.
Main Methods:
- Utilized transcranial magnetic stimulation (TMS) to map motor cortical representations of the first dorsal interosseous muscles in young and older adults across the handedness spectrum.
- Measured interhemispheric communication speed and bimanual coordination.
Main Results:
- Stronger hand dominance in older adults correlated with increased ipsilateral motor activity upon TMS, an effect absent in young adults.
- Interhemispheric communication speed and bimanual performance exhibited opposing relationships between the young and older adult groups.
Conclusions:
- Handedness is expressed differently in the motor cortices of young versus older adults.
- Age interacts with handedness to influence motor cortical organization and interhemispheric communication.
Related Concept Videos
01:33Somatosensation
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
01:14Motor and Sensory Areas of the Cortex
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
01:23Somatosensory, Motor, and Association Cortex
The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at the...
01:18Hierarchy of Motor Control
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
01:05Cerebral Hemispheres
The human brain, a complex organ, is functionally divided into two cerebral hemispheres—left and right. These hemispheres are interconnected by a structure of paramount importance, the corpus callosum. This substantial bundle of neural fibers is not just a bridge between the hemispheres but a crucial element for the brain's comprehensive functioning. It enables efficient communication between the two hemispheres, allowing each side of the brain to control and receive sensory and motor...
01:28Lateralization
Brain lateralization refers to the division of mental processes and functions between the two hemispheres of the brain, a phenomenon that optimizes neural efficiency and underpins complex abilities in humans. This specialization allows each hemisphere to perform tasks where it has a comparative advantage, facilitating more refined cognitive capabilities across different domains.