Rat Orbitofrontal Ensemble Activity Contains Multiplexed but Dissociable Representations of Value and Task Structure...

Area of Science:

• Neuroscience
• Cognitive Science
• Behavioral Science

Background:

• The orbitofrontal cortex (OFC) is crucial for adaptive behavior, with ongoing debate about its role in representing expected value versus cognitive maps.
• Existing theories often present these functions as mutually exclusive, but they may exist on a continuum influenced by task complexity and experience.

Purpose of the Study:

• To investigate whether the OFC represents a value-agnostic cognitive map or expected value signals.
• To explore how task complexity and experience shape OFC representations.
• To examine the coexistence of task structure and value representations in the OFC.

Main Methods:

• Recorded single-unit activity from the OFC in rats performing an odor sequence task.
• Designed the task with 24 unique positions defined by sensory information and reward likelihood, creating a mappable state space.
• Analyzed neural ensemble activity in relation to behavioral strategies and expected reward values.

Main Results:

• OFC neural ensembles showed representations closely matching the rats' use of the odor sequence task structure.
• A value-invariant representation of the task structure was observed.
• Simultaneously, representations of expected value at each location were also identified within the OFC.

Conclusions:

• The OFC appears to function as a cognitive map, adaptable to task demands and individual experience.
• Both task structure and expected value are represented distinctly but concurrently within the OFC's neural code.
• These findings support a unified model where the OFC integrates abstract task representations with specific value computations.