Aphantasia and Brain Connectivity: Insights from High-Resolution MRI Studies

Recent research using ultra-high-field 7T fMRI has shed light on the neural underpinnings of aphantasia, a condition characterized by the inability to visualize mental images. Conducted by scientists at the Paris Brain Institute and NeuroSpin, this groundbreaking study investigates how brain connectivity differs in individuals with aphantasia compared to those with typical mental imagery.

Visual imagery varies significantly among individuals—from vivid, movie-like mental scenes to barely perceivable silhouettes. Approximately 4% of the population experience aphantasia, a phenomenon known for over a century but only recently explored scientifically. This condition seems to be present from birth and may run in families. While not classified as a disorder, aphantasia is often linked with weaker autobiographical memory, face recognition challenges, and sometimes autism spectrum disorder, although these associations are yet to be fully understood.

To unravel the brain mechanisms behind aphantasia, researchers utilized 7T fMRI to observe brain activity during imagery and perception tasks. Unlike previous subjective assessments, this study employed objective measures, examining neural circuits involved in visual imagery and how they operate in individuals unable to generate mental images.

The study involved 10 aphantasic participants and 10 with typical imagery, all subjected to tasks that required recalling visual details of familiar objects, faces, and places. Results revealed that attempting mental imagery activates certain brain networks responsible for attention, awareness, and visual recognition, including the fronto-parietal network and areas like the fusiform gyrus and ventral temporal cortex.

Interestingly, even in aphantasic individuals, these regions showed activation; however, their functional connectivity was notably reduced. This suggests that while the brain regions are capable of activation, their communication efficiency is compromised, potentially explaining the lack of mental imagery.

The findings support the hypothesis that the quality of visual experience hinges on the integration between sensory processing areas and higher cognitive networks. The prefrontal cortex may play a causal role in the awareness of mental images.

Importantly, the study underscores that mental imagery, while influential for reasoning and creativity, is not essential for understanding or memory. Further research may reveal whether different subtypes of aphantasia exist, depending on causative factors. These insights deepen our understanding of how perception, memory, and imagination are interconnected in the brain.

For more detailed insights, see the full study published in Cortex (2025): [DOI: 10.1016/j.cortex.2025.01.013].

Source: https://medicalxpress.com/news/2025-06-aphantasia-linked-brain.html