The investigators aim to understand the interplay and neural structures involved with decision--making and movement for participants with mild cognitive impairment. Rapidly deciding and acting becomes bottlenecked with mild cognitive impairment and Alzheimer's, leading to detrimental outcomes such as falling and car crashes. The investigators work will have a tangible impact by discovering sensitive biomarkers to detect disease onset and pave the way for informed and effective neurorehabilitation.

Mild cognitive impairment leads not only to impaired decision making, but also movement deficits that predict the development of Alzheimer's disease. Recent behavioral work has suggested a common mechanism that throttles the speed of both decisions and reaching movements, which is supported by converging neural evidence that finds an interac-tion between decision making and movement (motor) circuits. Yet it remains unknown how the interplay between decision making and motor neural circuits becomes impaired and impedes rapid responses for those with mild cognitive impairment. Here the investigators test the central hypothesis that there is an impaired interaction between decision making and motor neural circuits with mild cognitive impairment.

First, the investigators will use human reaching experiments to establish that mild cognitive impairment disrupts the interplay of decision making and motor control. Second, the investigators will use Magnetic resonance elastography to elucidate whether brain stiffness in decision making and motor brain regions are related to altered movement behavior. The expected outcome is a mechanistic understanding of how impaired decision making and motor neural circuits impact movement for those with mild cognitive impairment.

Inclusion Criteria:

1. age 45 - 90 years
2. Perfect or corrected vision
3. Ability to reach
4. Neurotypical Age-Matched control participants - No history of neurological disorders or injury.
5. Mild Cognitive Impairment participants - clinical diagnosis of amnestic mild cognitive impairment.

Exclusion Criteria:

1. Any injury or condition that impacts reaching
2. Traumatic brain injury, such as concussion, in the last 6 months.
3. Neurotypical Age-Matched control participants: Modified Telephone Interview for Cognitive Status (TICS-m) score < 34
4. Mild Cognitive Impairment participants: Modified Telephone Interview for Cognitive Status (TICS-m) score > 34
5. Mild Cognitive Impairment participants: Mini-Mental State Examination Second Edition (MMSE-2) score < 21.