This study aims to investigate the brain activation during different motor patterns, including motor execution (ME), motor imagery (MI), action observation (AO) and mirror visual feedback (MVF). In addition, the relations between brain activation and motor performance will also be explored. This study includes two parts, which are upper limb and lower limb part. While executing all the tasks, brain activation in primary motor cortex(M1), premotor cortex(PMC), and supplementary motor cortex(SMA) will be monitored by functional near-infrared spectroscopy. One-way ANOVA with repeated measure will be used to detect the differences of brain activation level between each mode. Pearson correlation coefficient will be used to determine the relations of brain activation and motor performance.

In upper limb part, subjects will be instructed to execute functional reaching task in ME, MI, AO, and MVF mode. During ME mode, motor performance including maximum speed, maximum acceleration, and jerk will be collected simultaneously. In the lower limb part, subjects will be instructed to walking over ground in ME, MI, and AO mode. During ME mode, the temporal and spatial gait parameters, including speed, stride time, cadence, and stride length will be collected.

• Inclusion Criteria

  1. Age between 20 to 30 years.
  2. Right-handed.
  3. Ability to walk 30 meters independently without an assistive device.
  4. No neurogical, cardiopulmonary, or muscle diseases that might interfere with the experiment.
  5. Mini-Mental State Examination (MMSE) score greater than 24.

• Exclusion Criteria 1. Physiological condition is unstable.

The population in this study are heathly adults.