The Motor System

Brain Functions in Voluntary Movement

• The primary motor cortex, located in the frontal lobe of the brain, is responsible for initiating and coordinating voluntary movements.
• Voluntary movements involve the activity of several different brain areas, primarily the motor cortex.

Corticospinal Tract

• The corticospinal tract is a major pathway that conducts impulses from the brain to the spinal cord, facilitating voluntary motor control.
• It plays a crucial role in controlling fine motor skills, especially in the limbs and hands.

Interaction with Motor Areas

• The basal ganglia, a group of nuclei located deep within the cerebral hemispheres, interacts with the primary motor area, aiding in the planning and execution of movements.
• This interaction ensures smooth and coordinated movements, preventing unwanted muscle contractions.

Descending/Indirect Tracts

• Other descending or indirect tracts in the brain are responsible for regulating involuntary motor functions, such as posture and muscle tone.
• These tracts help in integrating sensory information and adapting movements accordingly.

Role of Basal Nuclei

• Basal nuclei play a critical role in initiating and regulating voluntary movements while inhibiting excessive movement.
• They are involved in the modulation of motor commands, ensuring that movements are purposeful and not jerky or disorganized.