# Ischemic lesions to the inferior frontal cortex slow perceptual switching

## TL;DR

Brain damage to the inferior frontal cortex slows how quickly people switch between different interpretations of ambiguous visual stimuli.

## Contribution

This study shows that IFC damage specifically affects perceptual switching, independent of lesion size or stroke severity.

## Key findings

- Patients with IFC lesions had fewer perceptual changes compared to those without IFC lesions.
- The effect remained after accounting for age, sex, stroke burden, and non-perceptual performance.
- The findings suggest the IFC contributes to updating conscious perception under sensory ambiguity.

## Abstract

In bistable perception, conscious experience alternates between two interpretations of an ambiguous stimulus. Functional imaging shows the activation of the inferior frontal cortex (IFC) during such reversals. However, it has remained unclear whether IFC involvement reflects post-perceptual processes such as attention or motor behavior, or contributes to perceptual updating itself. We examined bistable perception in patients with chronic ischemic stroke lesions. Patients with right middle cerebral artery (rMCA) lesions affecting the IFC (n = 8) exhibited fewer spontaneous perceptual changes than those with rMCA lesions sparing the IFC (n = 13), after controlling for age, sex, stroke burden, and non-perceptual task performance. Group differences were observed in a small sample with heterogeneity in lesion characteristics, including lesion volume and severity, which limit definitive causal inference. These preliminary results indicate that IFC damage slows updating of conscious experience in response to ambiguous sensory input, supporting a contributory role of the prefrontal cortex in shaping conscious perception.

•Ischemic lesions involving the inferior frontal cortex alter bistable perceptual dynamics•Patients with IFC lesions show reduced rates of perceptual switching after stroke•Effects persist after controlling for lesion volume and clinical stroke severity•Findings support a role of the IFC in updating perception under sensory ambiguity

Ischemic lesions involving the inferior frontal cortex alter bistable perceptual dynamics

Patients with IFC lesions show reduced rates of perceptual switching after stroke

Effects persist after controlling for lesion volume and clinical stroke severity

Findings support a role of the IFC in updating perception under sensory ambiguity

Imaging anatomy; Radiology; Cognitive neuroscience