Motor imagery beyond the joint limits: a transcranial magnetic stimulation study

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Neuroscience

Background:

• Motor imagery and execution share neural processes.
• Humans can imagine movements beyond their physical capabilities.
• Understanding the neural basis of movement plausibility is key.

Purpose of the Study:

• To investigate if movement plausibility is mapped in the corticospinal motor system.
• To determine the influence of visuomotor versus kinesthetic-motor imagery strategies.
• To explore the neural mechanisms underlying imagined movements.

Main Methods:

• Healthy subjects performed motor imagery of possible and impossible finger movements.
• Single pulse transcranial magnetic stimulation (TMS) of the left motor cortex was used.
• Corticospinal excitability was measured during motor imagery.

Main Results:

• Motor imagery increased corticospinal excitability.
• This increase was greater for impossible movements than for possible movements.
• The effect was specific to the muscle involved in the imagined movement.

Conclusions:

• Movement plausibility is computed in brain regions before the primary motor cortex.
• Motor imagery is a higher-order cognitive process.
• Motor imagery is not strictly bound by the physiological constraints of motor execution.