The Brain's Traffic Controllers

Cognitive control is the brain's ability to prioritize goals over impulses—like choosing salad over pizza when dieting. This "top-down" regulation:

• Suppresses automatic responses (e.g., resisting a smartphone distraction)
• Engages deliberative processes (e.g., learning a new skill) ^{2 6}

When control falters, we see perseveration errors—repeating failed actions, common in addiction or OCD ^{1 8} .

Two players dominate this circuit:

• Prefrontal cortex (PFC): The planner. Its subregions include:
  • Orbitofrontal cortex (OFC): Computes reward values ("Is that chocolate worth the calories?")
  • Dorsolateral PFC (dlPFC): Implements rules ("Stick to the diet!") ^{4 7}
• Striatum: The habit enforcer. Divided into:
  • Ventral striatum (e.g., nucleus accumbens): Processes rewards
  • Dorsal striatum: Stores automated behaviors ^{1 5}

Their communication creates a ventral-dorsal functional gradient:

• Ventral circuits drive reward-seeking ("Eat that chocolate!")
• Dorsal circuits promote goal-directed control ("Remember your diet!") ⁵

Figure 1: Frontostriatal circuits involved in reward processing and cognitive control.

In healthy brains, PFC flexibly modulates striatal activity. But in psychiatric disorders:

Task Design: Monkeys performed a state-dependent decision task with three states:

Choices required selecting visual cues with reward values that changed based on the state.

Neural Recording:

• Neuropixel probes recorded 1,293–1,528 OFC neurons and 1,085–1,149 caudate (CdN) neurons simultaneously.
• Local field potentials (LFPs) measured rhythmic oscillations between regions.

Analysis Techniques:

• Sliding-window ANOVA: Identified neurons encoding state, value, or their interaction.
• Linear Discriminant Analysis (LDA): Decoded 12 distinct "value states" from population activity.
• Alpha-band coherence: Measured OFC→CdN synchronization directionality using Hilbert transforms ² .

State-Dependent Encoding:

• OFC neurons encoded value earlier than CdN (120 ms vs. 180 ms post-cue), especially in conflict states.
• During conflicts, OFC activity rapidly toggled between competing values (e.g., "Option X in State A" vs. "Option X in State B").

Corrective Behaviors and Neural Volatility:

Monkeys made corrective saccades (rapid eye movement corrections) during errors. These were linked to:

• OFC "neural volatility": Fluctuations between competing value representations.
• CdN suppression: Fewer value-encoding neurons during conflicts.

Alpha Coherence as a Braking Signal:

Alpha-band (8–16 Hz) coherence surged before corrective saccades. Crucially:

• OFC activity preceded CdN by 15 ms (amplitude cross-correlation).
• Coherence strength directly correlated with OFC volatility (r = 0.72, p = 0.008).

This experiment revealed a two-stage control mechanism:

1. OFC generates alternatives during conflicts (high volatility).
2. Alpha-band coherence suppresses striatal routines, allowing behavioral flexibility ^{2 6} .