Attention versus intention in the primate premotor cortex.

Area of Science:

• Cognitive Neuroscience
• Neurophysiology
• Primate Neurobiology

Background:

• Dissociating mental processes like attention and motor preparation is crucial for understanding brain function.
• The dorsal premotor area (PMd) is involved in movement planning and execution, receiving input from the dorsolateral prefrontal cortex (DLPf).
• Previous research suggests PMd neurons are active during tasks with instructed delays, but their specific roles in attention versus movement preparation require clarification.

Purpose of the Study:

• To dissociate neuronal activity related to visuo-spatial attention from preparatory activity in the monkey brain.
• To investigate the functional organization of the dorsal premotor cortex (PMd) in relation to attention and motor preparation.
• To compare findings in monkeys with human functional magnetic resonance imaging (fMRI) data.

Main Methods:

• Neurophysiological recordings of cell activity in the dorsal premotor area (PMd) of monkeys.
• Comparison of PMd cell activity with that of the dorsolateral prefrontal cortex (DLPf).
• Functional magnetic resonance imaging (fMRI) study in humans comparing premotor activation during spatial attention/memory and motor preparation tasks.

Main Results:

• Many PMd cells are active during tasks involving attending to visual stimuli, not solely movement preparation.
• A rostrocaudal specialization exists within PMd: attention-related neurons are more frequent rostrally (PMdr), and intention-related neurons caudally (PMdc).
• Human fMRI data revealed similar rostrocaudal specialization in PMd, with attention-related activation rostrally/medially and intention-related activation caudally.

Conclusions:

• The dorsal premotor cortex (PMd) exhibits functional specialization for visuo-spatial attention and motor preparation.
• There are strong similarities in the functional organization of the dorsal premotor cortex between humans and monkeys.
• This specialization aids in dissociating distinct cognitive and motor processes within the brain.