Study Links Aphantasia to Changes in Brain Connectivity

Recent research conducted by scientists at the Paris Brain Institute and NeuroSpin has uncovered potential links between aphantasia and changes in brain connectivity. Aphantasia, characterized by the inability to visualize images mentally, affects around 4% of the population and has been a subject of curiosity for over a century.

The study, published in the journal Cortex, utilized advanced 7T fMRI technology, enabling researchers to explore the neural mechanisms underlying visual imagery at unprecedented resolution. This exploration is vital for understanding the cognitive processes involved in visualizing scenes, people, or objects that are not currently visible.

Visual imagery varies significantly among individuals; some can vividly recall landscapes or faces, while others may struggle to form even the faintest mental image. Aphantasia is not classified as a disorder, but it is often associated with challenges in autobiographical memory, face recognition, and, in some cases, autism spectrum disorder.

According to researchers, aphantasia may stem from inherent differences in brain function. The current study aimed to investigate the neural circuits involved in mental imagery and visual perception in both aphantasic individuals and those with typical mental imagery capabilities.

To achieve this, the research team recruited a group of 10 individuals diagnosed with aphantasia alongside 10 individuals with typical visual imagery skills. Participants underwent ultra-high-field functional MRI while responding to questions about the visual characteristics of familiar objects, words, and faces.

The findings revealed that while aphantasic individuals reported no experiential imagery, their brains still activated certain regions typically associated with visual processing. However, the connectivity between these areas was notably reduced compared to individuals with typical imagery abilities.

Specifically, regions within the fronto-parietal networks, responsible for attention and working memory, were less communicative in aphantasic subjects. This reduced connectivity may elucidate why individuals with aphantasia can retain accurate visual knowledge of objects, even without the ability to visualize them. For instance, they may remember the distinct color differences between various vegetables.

The researchers propose that the integration of visual information between the fronto-parietal networks and visual perception areas is crucial for the quality of visual experiences, whether they arise from perception or imagination. The left prefrontal cortex may play a significant role in this process.

Future research is anticipated to explore whether aphantasia presents uniformly among all affected individuals or if there are distinct subtypes linked to varying underlying causes. This ongoing investigation not only enhances understanding of aphantasia but also sheds light on the broader relationships between mental imagery, perception, memory, and neurodevelopment.

Ultimately, these studies highlight the diverse ways individuals experience the world, demonstrating that mental imagery is not a necessary component for reasoning, creativity, or conceptualization.