Final answer:
A lesion in the left subthalamic nucleus can lead to various motor symptoms associated with Parkinson's disease.
Step-by-step explanation:
Effect of Lesion in the Left Subthalamic Nucleus
A lesion in the left subthalamic nucleus (STN) can result in several motor symptoms associated with Parkinson's disease (PD). The STN is part of the basal nuclei and plays a crucial role in regulating movement. Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra, leading to reduced dopaminergic innervation in the basal ganglia. The indirect pathway within the basal nuclei, including the STN, becomes overactive, resulting in hypokinetic symptoms such as resting tremors, slowed movement, and balance problems.