Cortical steady potential shifts and anodal polarization during delayed response performance

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Primate Behavior

Background:

• Delayed Response (DR) tasks are crucial for studying short-term memory.
• Cortical steady potentials (SPs) offer insights into neuronal activity during cognitive tasks.
• Prefrontal cortex plays a key role in executive functions and memory.

Purpose of the Study:

• To investigate the neural correlates of short-term spatial memory during DR tasks in monkeys.
• To examine the effect of prefrontal cortex polarization on DR task acquisition.

Main Methods:

• Monkeys were trained on DR tasks with chronically implanted electrodes in prefrontal, precentral, and occipital cortex.
• Cortical steady potentials (SPs) were recorded during DR trials.
• Surface anodal polarization was applied to the prefrontal cortex during task acquisition.

Main Results:

• Three distinct SP shifts were identified during DR trials: expectancy, reinforcement, and short-term spatial memory formation.
• A prefrontal SP shift correlated significantly with correct performance, suggesting a role in memory.
• Anodal polarization of the prefrontal cortex facilitated DR task acquisition rates.

Conclusions:

• Prefrontal cortex activity, specifically SP shifts, is associated with short-term spatial memory and task performance.
• Modulating prefrontal cortex excitability can enhance learning and performance on DR tasks.
• Findings support the role of prefrontal neuronal excitability changes in cognitive performance.