Dissociating bottom-up and top-down processes in a manual stimulus-response compatibility task.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Motor Control

Background:

• Motor response speed and accuracy are modulated by spatial relationships between stimuli and responses.
• Bottom-up attention enhances responses with high spatial overlap, while top-down processes are needed for low overlap via reorientation.

Purpose of the Study:

• Investigate the interaction between bottom-up and top-down attentional processes in motor responses.
• Identify neural substrates underlying stimulus-response compatibility effects.

Main Methods:

• Utilized a spatial stimulus-response compatibility task with lateralized visual stimuli.
• Recorded brain activity using functional neuroimaging during congruent and incongruent conditions.

Main Results:

• Stimulus-driven bottom-up processes showed activation in V5, intraparietal sulcus (IPS), and premotor cortex (PMC).
• Incongruent responses activated bilateral IPS, PMC, anterior insula, dorsolateral prefrontal cortex (DLPFC), and temporoparietal junction (TPJ).
• A distinct region in the IPS was linked to top-down reorienting of motor attention.

Conclusions:

• Contralateral IPS and PMC activations support the behavioral advantage in congruent responses.
• Involvement of insula, DLPFC, and TPJ reflects top-down control for task demands in incongruent responses.
• The IPS shows overlapping and distinct neural substrates for bottom-up and top-down attention.