The spinal cord is a very important part of the central nervous system. fMRI can be applied to observe functional status of the human spinal cord. Under different conditions, the investigators will see different types of fMRI signals within the spinal cord. In resting state, the investigators might see active/inactive signals, too.

Inclusion Criteria (for healthy people):

• Chinese male residents
• right handed
• no history of psychological/psychotic problems
• no history of important diseases

Exclusion Criteria (for healthy people):

• with factors which make subjects unsuitable to receive MR examination
• history of important diseases

Inclusion Criteria (for patients):

• Chinese male patients with ischemic stroke (CT/MRI scan confirmed)
• right handed
• at least 1.5 months from onset of stroke
• ability to follow complex commands

Exclusion Criteria (for patients):

• hemodynamic instability
• history of dementia
• inability to give consent because of impaired cognition or receptive aphasia
• diseases in spine/spinal cord
• with factors which make subjects unsuitable to receive MR examination

group 1: male residents of Beijing group 2: male stroke patients of Beijing Boai hospital