Delay-period activity in the primate prefrontal cortex encoding multiple spatial positions and their order of...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Primate Research

Background:

• The prefrontal cortex is crucial for executive functions, including working memory and planning.
• Understanding how neurons represent complex spatial information is key to deciphering cognitive processes.

Purpose of the Study:

• To investigate if prefrontal neurons can temporarily retain information about multiple spatial positions and their temporal order.
• To identify the types of neural activity supporting the representation of sequential spatial information.

Main Methods:

• Single-neuron activity was recorded in monkeys performing a delayed sequential reaching task.
• Monkeys were required to remember two out of three cue positions and their presentation order.
• Neurons were also tested on a conventional delayed reaching task for comparison.

Main Results:

• 72 neurons showed significant delay-period activity.
• 19 neurons were position-dependent, with 13 showing order-dependent activity.
• 39 neurons were pair-dependent, with 32 showing order-dependent activity.
• New types of activity, pair-dependent and temporal order-dependent, were observed.

Conclusions:

• Single prefrontal neurons can retain information about two spatial positions and their temporal sequence.
• Pair-dependent and temporal order-dependent activities are novel mechanisms for complex spatial memory.
• The dorsolateral prefrontal cortex is vital for planning sequential behaviors involving spatial information.