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Interoception, insula, and agency: a predictive coding account of aphantasia

DOI: 10.3389/fpsyg.2025.1564251
Silvanto, J. (2025). Interoception, insula, and agency: a predictive coding account of aphantasia. Frontiers in Psychology, 16. doi:10.3389/fpsyg.2025.1564251

Abstract

Researchers have proposed a new explanation for aphantasia—the inability to voluntarily create mental images—suggesting it may result from how our brain processes internal bodily signals (called interoception) through a brain region called the insula. The theory has two key components: individuals with aphantasia may struggle to integrate bodily sensations with mental processes, which normally gives imagery its "embodied" quality, and they may experience reduced "sense of agency" over generating mental images. Using a "predictive coding" framework, researchers suggest our brain normally creates mental imagery through top-down predictions from higher brain regions to sensory areas, but in aphantasia, these predictions don't receive enough amplification due to reduced precision of interoceptive signals, preventing imagery from reaching conscious awareness. Interestingly, many people with aphantasia can still experience visual dreams, suggesting the issue isn't with visual processing itself but with voluntary image creation, and the theory also explains why people with aphantasia often have difficulties integrating information across different senses.

Authors

  • Juha Silvanto5

Understanding Aphantasia: A New Perspective

Overview/Introduction

Aphantasia is a condition where individuals cannot voluntarily create mental images. This research paper proposes a novel explanation for aphantasia, suggesting that it may be linked to how the brain processes internal bodily signals, known as interoception, through a specific brain region called the insula. The study introduces a theory that highlights two main components: difficulties in integrating bodily sensations with mental processes, and a reduced "sense of agency" over generating mental images.

Methodology

The researchers utilized a predictive coding framework to explore how mental imagery is generated in the brain. Normally, the brain creates mental images through predictions from higher brain regions to sensory areas. In aphantasia, these predictions lack sufficient amplification due to reduced precision of interoceptive signals, preventing images from reaching conscious awareness. The study also examined the role of the insula and its interactions with other brain regions like the prefrontal cortex and the anterior cingulate cortex.

Key Findings

  • Interoception and the Insula: The insula plays a crucial role in integrating bodily signals with mental processes. In people with aphantasia, this integration is disrupted, leading to difficulties in generating mental images.
  • Sense of Agency: Individuals with aphantasia may experience a reduced sense of control over their mental imagery, similar to how motor control systems anticipate movement outcomes.
  • Cross-Modal Processing: The study found evidence of impaired integration of sensory information across different modalities in aphantasia, which supports the theory of disrupted interoceptive processing.
  • Visual Dreams: Despite difficulties with voluntary image creation, many people with aphantasia can still experience visual dreams, indicating that the issue is not with visual processing itself.

Implications

This new understanding of aphantasia could have significant implications for how we approach and support individuals with this condition. By recognizing the role of interoception and the insula, therapies could be developed to enhance the integration of bodily signals and improve the sense of agency over mental imagery. This research also opens up new avenues for exploring how the brain processes sensory information and the intricate connections between different brain regions.

Limitations

While the study provides a compelling explanation for aphantasia, it is primarily theoretical and based on existing models of brain function. Further empirical research is needed to validate these findings and explore potential interventions. Additionally, the complexity of brain processes means that other factors may also contribute to aphantasia, which were not addressed in this study.
In summary, this research offers a fresh perspective on aphantasia by linking it to interocep...