Subthreshold basis for reward-predictive persistent activity in mouse prefrontal cortex.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Persistent neural activity is crucial for internal information maintenance in nervous systems.
• The precise mechanisms generating persistent activity in the prefrontal cortex (PFC) remain incompletely understood.

Purpose of the Study:

• To investigate the mechanisms underlying reward-predictive persistent activity in the mouse prefrontal cortex (PFC).
• To determine how persistent activity encodes information about reward timing and probability.
• To explore the layer- and cell-type specificity of persistent activity in the PFC.

Main Methods:

• Electrophysiological recordings of membrane potential (Vm) from pyramidal neurons across different layers of the mouse PFC.
• Behavioral tasks where stimuli predict rewards with varying delays and probabilities.
• Analysis of mean and variance of Vm, firing rates, and intracellular perturbations.

Main Results:

• Reward-predictive persistent firing increases in PFC are associated with sustained increases in Vm mean and variance.
• Persistent activity is terminated by reward receipt or centrally generated mechanisms linked to reward expectation.
• Distinct neuronal populations exhibit persistent depolarization (upper L5) or hyperpolarization (lower L5), while L2/3 neurons show no persistent activity.

Conclusions:

• Reward-predictive persistent activity in the PFC is spatially organized across layers and cell types.
• This activity is dynamically regulated by synaptic mechanisms and conveys information about internal states related to reward expectation.
• The findings highlight the role of specific PFC circuits in maintaining and processing temporally relevant information.