What are the mechanisms that construct our experience of reality?

The role of the inferior frontal cortex in resolving sensory ambiguity.

Overview

Sensory information is often noisy, incomplete, and ambiguous. Yet the brain usually constructs a coherent experience of reality. My research asks how higher-order regions, particularly the inferior frontal cortex (IFC) and the anterior insula, help resolve ambiguity in perception and update our internal model of the world.

Key Findings

1. The IFC supports perceptual updating

Across experiments with ambiguous visual stimuli, the IFC emerged as a key region for switching between competing interpretations. When we temporarily disrupted IFC activity using Transcranial Magnetic Stimulation (TMS), perceptual transitions slowed. This suggests that the IFC contributes causally to updating conscious experience under uncertainty.

2. The insula signals violated expectations

The anterior insula, together with the IFC, responded strongly when events deviated from spatial or temporal expectations. This pattern suggests that the insula helps detect prediction failures and trigger the adjustments needed to keep perception aligned with the environment.

3. Damage to IFC reduces perceptual flexibility

In stroke patients with damage to the IFC, spontaneous shifts in perception during ambiguous tasks were reduced. This supports the idea that intact frontal circuitry is important for keeping perception flexible rather than fixed.

Methods

To address these questions, we combine:

Implications

These findings support predictive processing accounts in which the brain continuously compares sensory input with internal predictions. They also suggest that the IFC is not merely correlated with perceptual changes, but helps implement them. More broadly, this work may inform interventions for disorders marked by overly rigid or unstable perceptions.

Future Directions

Looking ahead, we plan to:

Resources