Electrophysiological population dynamics reveal context dependencies during decision making in human frontal cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Science

Background:

• The orbitofrontal cortex (OFC) is implicated in encoding subjective value during decision-making in both humans and non-human primates.
• Previous research in non-human primates suggested that these value signals are context-dependent, influenced by recent experiences.

Purpose of the Study:

• To investigate the presence and representation of subjective value and context-dependent value signals in the human OFC.
• To determine if theoretical predictions of context dependency in value signals could be observed in human frontal cortical activity.

Main Methods:

• Utilized an auction task with human epilepsy patients undergoing monitoring with distributed electrodes.
• Recorded high-gamma activity across cortical and subcortical sites, including the OFC, while patients reported subjective values for snack food items.
• Analyzed neural activity for correlations with reported subjective values and contextual modulations based on previous choices.

Main Results:

• High-gamma activity in multiple brain regions, including the OFC, positively correlated with the subjective value of items.
• Identified specific OFC sites exhibiting signals modulated by the subjective value of previously evaluated items, demonstrating context dependency.
• Observed simultaneous but separate neural representations of item value and value-context signals within human frontal cortical activity.

Conclusions:

• Human OFC activity simultaneously encodes both absolute subjective value and context-dependent value signals during choice tasks.
• These findings provide the first direct evidence in humans for context-dependent value modulation in the OFC, aligning with theoretical predictions.
• The distinct representation of value and value-context signals in the OFC offers new insights into the neural basis of complex decision-making.