Supplementary motor area

Definition

The supplementary motor area (SMA) is a region of the brain located in the frontal lobe, specifically on the medial surface, and plays a critical role in the planning and coordination of voluntary movements. It is involved in the initiation of movement sequences and the integration of sensory information to facilitate complex motor tasks. The SMA works in conjunction with other areas of the motor cortex to execute well-learned and sequential movements, highlighting its importance in the broader framework of motor control.

5 Must Know Facts For Your Next Test

1. The SMA is crucial for initiating movements that require more than one muscle group, such as playing a musical instrument or typing.
2. It has a strong connection with the primary motor cortex, allowing for seamless communication when planning and executing movements.
3. Research shows that the SMA becomes active during mental rehearsal of movements, indicating its role in movement planning even before physical execution.
4. Damage to the SMA can lead to difficulties in performing complex movements, often referred to as apraxia.
5. The SMA is also implicated in tasks that require bimanual coordination, where both hands need to work together harmoniously.

Review Questions

• How does the supplementary motor area contribute to the planning and execution of voluntary movements?
  • The supplementary motor area (SMA) plays a vital role in planning voluntary movements by integrating sensory information and sequencing movements. It works closely with the primary motor cortex to translate these plans into actual physical actions. The SMA is particularly important for complex tasks that involve multiple muscle groups or require coordination between both hands, ensuring that these actions are smooth and well-timed.
• Discuss how damage to the supplementary motor area can impact an individual's ability to perform coordinated movements.
  • Damage to the supplementary motor area can lead to significant impairments in an individual's ability to perform coordinated movements, often manifesting as apraxia. This condition results in difficulties with planning and executing learned tasks, making it hard for individuals to carry out activities that require fine motor skills or bimanual coordination. Even if they have intact strength and sensation, individuals may struggle with organizing their movements effectively due to the SMA's compromised function.
• Evaluate the significance of the supplementary motor area in the context of neuroplasticity and rehabilitation following a stroke.
  • The supplementary motor area is significant in neuroplasticity and rehabilitation because it demonstrates the brain's ability to adapt following injury, such as a stroke. Rehabilitation efforts often focus on engaging the SMA through repetitive task practice and mental imagery techniques, which can help rewire neural pathways and restore movement capabilities. By harnessing the SMA's role in planning and sequencing movements, therapists can encourage functional recovery, making it an essential target for interventions aimed at improving motor skills post-stroke.

Related terms

primary motor cortex:

The primary motor cortex is the region of the cerebral cortex responsible for executing voluntary movements by sending signals to various muscles throughout the body.

premotor cortex:

The premotor cortex is involved in planning and organizing movements, particularly in response to external cues and in coordinating complex actions.

basal ganglia:

The basal ganglia are a group of nuclei in the brain that play an essential role in coordinating movement, regulating motor control, and facilitating smooth execution of voluntary actions.