**2. Materials and methods**

The human arm is capable of performing seven basic motions associated with joints in the human arm. To account for transhumeral amputation, three of the main arm motions are considered i.e. one elbow and two motions affiliated with the wrist joint. These motions comprise wrist extension (WE), elbow flexion (EF), wrist supination (WS), wrist flexion (WF), elbow extension (EE), and wrist pronation (WP).

This section elaborates on the data acquisition of the defined motions. These motions were captured using The NIRsport manufactured by NIRx Technologies. It is an accessible, segmental, and robust functional near-infrared spectroscopy (fNIRS) machine that measures hemodynamic responses generated by neuroactivation of the inside brain via oxy-, deoxy-, and total hemoglobin variations in the cerebral cortex.

The updated version, NIRsport-2 proposes a host prepared to implement advancements and units to meet the requirements of wide-ranging cognitive neuroscience applications. The major advantage of this device is that it is designed to work in a rugged environment and also this device is portable. This feature aids in the development of a wearable and portable system.
