Movesci 2.4

Introduction to Action Observation in the Brain

• During action observation, individuals may experience activity in the ipsilateral hemisphere of the brain despite the observed action being performed by another.

• Signals related to movement cross over in the medulla, meaning the right brain controls the left side of the body and vice versa.

  • For example, if a person has a lesion in the motor region of the left hemisphere, their right hand can still respond as if it were their left hand.

Role of Mirror Neurons

• Mirror neurons activate during action observation, causing individuals' brains to "mimic" the observed actions.

  • These neurons are essential for understanding actions and intentions of others.

  • When observing someone performing an action, the brain shows activity in the same areas as if the observer were performing the action themselves.

• Visualization and observation trigger signals to motor areas, enabling movement even in the presence of brain lesions.

Understanding Rehabilitation Through Action Observation

• Mirror neuron activity can be particularly beneficial for rehabilitation, especially after strokes when physical movement is challenging.

• Observing left-hand movements, for instance, activates the right side of the brain, reinforcing neurological pathways even if there are existing motor impairments.

  • This activation can help accelerate recovery by enhancing brain plasticity.

Mechanism of Mirror Box Therapy

• Mirror box therapy is used to aid recovery in individuals with motor impairments:

  • Involves a mirroring technique where a patient can see their unaffected limb's reflections as their affected limb.

  • This visual feedback engages the brain's mirror neurons, allowing the brain to perceive movement in the affected limb, which may prompt actual movement over time.

• In therapy, engagement with the unaffected limb can lead to similar motor prompts for the affected limb, aiding in rehabilitation.

Evidence of Efficacy

• Studies show that when individuals engage in practice tasks while receiving visual feedback of their moving limbs, they show significant increases in the size and intensity of motor output maps.

  • For instance, a substantial growth from 1 cm² to 14 cm² is observed in motor neuron output over a five-day piano practice.

• Additionally, activities like the pegboard task demonstrate measurable outcomes in terms of timing and accuracy, consistently showcasing performance improvements in motor function through repeated practice.

Conclusion and Practical Applications

• Monitoring the development of motor skills pre- and post-rehabilitation provides insight into the brain-behavior relationship following strokes or motor system impairments.

• Suggested experimental designs involving pegboard tasks aim to evaluate the effectiveness of mirror box therapy in improving motor function, using measures such as time to complete tasks, accuracy, and motor output metrics to quantify success and improvements in rehabilitation outcomes.