Visual spatial attention has opposite effects on bidirectional plasticity in the human motor cortex.

Area of Science:

• Neuroscience
• Cognitive Science
• Motor Control

Background:

• Synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), is crucial for learning and memory.
• The interplay between LTP and LTD shapes neural connections in the brain.
• The influence of cognitive factors like visual spatial attention on motor cortex plasticity is not fully understood.

Purpose of the Study:

• To investigate how visual spatial attention affects LTP-like and LTD-like plasticity in the human primary motor cortex.
• To determine if attention modulates the direction and magnitude of plasticity induced by paired associative stimulation (PAS).

Main Methods:

• Utilized paired associative stimulation (PAS) to induce LTP-like and LTD-like plasticity in the motor cortex.
• Assessed changes in cortical excitability via motor-evoked potentials.
• Manipulated visual spatial attention by having participants focus on stimuli near either the left or right hand during PAS.

Main Results:

• When attention was directed to visual stimuli near the stimulated (left) thumb, LTP-like plasticity was significantly enhanced.
• Conversely, LTD-like plasticity was reduced when attention was focused on the stimulated thumb.
• Attending to stimuli near the non-stimulated (right) thumb did not produce these modulatory effects.

Conclusions:

• Voluntary visual spatial attention significantly influences bidirectional plasticity in the human motor cortex.
• Attention acts to strengthen relevant neural connections and suppress irrelevant ones within the focus of attention.
• These findings highlight the dynamic interaction between cognitive states and neuroplasticity in motor control.