Breaking the Connectivity Code: How The Aphantasia Brain Access Visual Information Without the Mind's Eye

When Jianghao Liu asks someone to imagine a sandy beach from their last holiday, most people describe feeling the sunshine, seeing the waves, watching people walk along the shore. But some respond differently: "I know the concept and I feel like this concept. I organize information based on what I have already seen it in the real life, but I don't see or visualize the real image. I don't have visualize in my mind."

This response sparked a research journey that would challenge fundamental assumptions about how the brain creates our inner visual world. Liu, a brain researcher from the Paris Brain Institute and visiting scholar at Columbia University, has spent years unravelling one of neuroscience's most intriguing puzzles: how people with aphantasia can navigate visual questions with remarkable accuracy while experiencing no mental imagery at all.

The Matrix Question

Liu's path to aphantasia research began with an engineering background and a fascination with brain-computer interfaces. His inspiration came from an unexpected source:

"If you look at the film of The Matrix, what would be the ultimate information about the reality or virtual reality or imagination? We have to really understand the mental imagery because this is the subjective experience of trying to recreate the world."

Starting with typical visualizers, Liu's research took an unexpected turn when he discovered aphantasia.

"Visual mental imagery and understanding subjective experience is important. Aphantasia is a real example of people doing things differently, processing differently in the brain, but they still have the same visual life."

The Preserved Performance Paradox

Liu's behavioural study revealed something remarkable about people with aphantasia. When asked to compare visual characteristics—like whether a beaver or fox has a longer overall shape, which fruit has darker skin color a strawberry or cherry, or which French president has a rounder face—people with aphantasia performed just as accurately as vivid visualizers.

"Very surprising," Liu explains, "the aphantasia, typical imagers, and vivid imagers, they all have very similar accuracy in questions about the shape of objects."

But there was a catch.

"It seems that aphantasics always responds a little bit slower than the other groups and even vivid imagers—they responds quicker than the typical imagers. So since this vividness of the mental imagery could help extract or facilitate the visual information to respond to these imagery-related questions."

Even more intriguingly, this pattern held true not just for imagery tasks but for perception as well. When participants looked at actual pictures instead of imagining them, people with aphantasia still showed slightly slower response times, suggesting their brains were processing visual information differently even during regular vision.

The Confidence Gap

Perhaps most revealing was what happened when participants rated their confidence in their responses. People with aphantasia, particularly when judging facial characteristics, "rate a little bit less confidence score than the typical imagers. So I know I have this kind of visual information, but I'm not sure if I have the correct response."

This metacognitive difference—being less certain about correct judgments—provided a crucial clue.

"This behavioral study shows aphantasia they have preserved accuracy but their response slower in either imagery and perception, and they have lower confidence about this vision-related judgment of the characteristics."

The Fusiform Imagery Node Discovery

To understand what was happening in aphantasic brains, Liu's team turned to high-resolution fMRI scanning. Their fMRI research challenged the dominant model of mental imagery, which suggested that mental images were constructed in primary visual cortex (V1) like real visual perception, only in reverse.

Instead, Liu's team identified what they call the "fusiform imagery node"—a region in the left hemisphere between the occipital and temporal areas.

"Probably this fusiform imagery node could connect to other brain areas like frontal parietal areas or the hippocampus or the anterior temporal lobe to extract visual or semantic information and generate a vivid mental imagery based on these representations."

This discovery aligned with neurological case studies. As Liu notes, "Many cases show that the patients with the bilateral lesions in the early visual area, especially in this primary visual cortex, could still generate very vivid mental imagery."

Same Activation, Different Connection

When Liu's team scanned people with aphantasia during imagery tasks, they made a surprising discovery. The same brain regions are activated in both typical visualizers and people with aphantasia, including high-level visual areas that process specific categories like faces and words.

"Aphantasia very surprisingly you find also very similar activations in aphantasia while they don't have any visual phenomenology of each category but they do have this high-level visual activations probably which support this kind of extraction of the visual information."

The difference wasn't in which brain areas turned on—it was in how they communicated. In typical visualizers, the fusiform imagery node showed strong functional connectivity to frontal-parietal areas during imagery tasks.

"This communication network could be kind of the neural signature to generate mental imagery—widespread areas in different brain regions."

But in people with aphantasia,

"we only find very very local functional connectivities but not the functional connectivity to the frontal parietal regions. So basically aphantasia, the high-level visual areas do not connect or correlate with the frontal parietal activity either in perception or in imagery."

The Attention Network Disruption

Liu's research revealed another crucial piece of the puzzle: hyperactivity in what's called the ventral attention network in people with aphantasia. This network typically functions to interrupt ongoing processes when something urgent demands attention—like suddenly hearing a fire alarm while reading.

"Aphantasia have this abnormal ventral attention networks hyperactivity in the imagery and also in perception. Probably this kind of imagery process could be disrupted or interrupted during the generation or maintenance of the conscious mental imagery by these ventral attention networks."

But this disruption might serve a purpose. Liu found that people with aphantasia showed

"higher connectivity of this ventral attention network to the typical semantic network in the aphantasia brain. So it seems that okay I don't have mental imagery but if I want to solve this question I could use my semantic knowledge. So I need this network to cut this visual processing and reorient to the semantic network to extract that strategy."

Access Without Awareness

One of Liu's most significant insights relates to theories of consciousness. His research suggests that people with aphantasia have what researchers call "access consciousness"—the ability to access and use visual information—without "phenomenological consciousness"—the subjective experience of seeing mental images.

"Actually this is very interesting debate about the consciousness could be divided into the access consciousness or phenomenology consciousness. So probably aphantasia could be a kind of showcase to say that you have access to the information but you don't generate the phenomenology of consciousness."

This was demonstrated when Liu asked people with aphantasia to organize items by visual characteristics like color.

"Even aphantasia don't have mental imagery or phenomenology they could arrange items in a very very similar way as typical imagers. So actually this kind of arrangement task of the visual characteristics in imagery probably don't need the visual phenomenology or visualizing the items."

The Strategy Spectrum

Liu's interviews with people with aphantasia revealed the diversity of strategies they develop.

"I was talking with my participants. There was a couple with aphantasia, so both are aphantasic, and actually they answered the questions very very differently."

Some approaches were remarkably sophisticated:

"Ask them to draw the building where they live, the facade of the building, the street scene— there was a guy who drew it in 3D view."

This variability in strategies helps explain performance differences.

"Aphantasia depends really on what kind of strategy they have developed by themselves. So they have different efficiency of the strategy. A lot of efficient strategy could be used to solve these kind of questions."

Beyond Visual Aphantasia

Liu's research extends beyond visual imagery to other sensory modalities.

"I have interviewed a lot of aphantasia participants, it seems they have have different domain-specific networks or sensory networks. Due to this different phenomenology of the imagery for those visual aphantasia they have problems of connectivity between this visual sensory cortex to the associate cortex but for other modalities they have this modality-specific area connectivity."

This suggests that different types of aphantasia—visual, auditory, tactile—likely follow similar patterns, with connectivity disruptions occurring between the relevant sensory brain areas and frontal attention networks.

While someone with only visual aphantasia has a localized connectivity issue, global aphantasia indicates more widespread difficulties with the brain's general coordination systems, explaining why some people retain rich auditory or tactile imagery while lacking visual imagery, while others report no mental imagery across any sensory modality.

The Constructive Nature of Vision

Liu's work reveals something profound about how all brains construct visual experience.

"Our vision either in typical imagers or in aphantasia, it's kind of the link between the external reality and internal phenomenology. Actually, this processing is different but fundamentally our vision is kind of constructive mechanism. It's not a directly copy of the external objects."

Liu's research reveals that all brains actively construct visual experiences rather than simply replaying stored images. For people with aphantasia, this construction process works differently. While typical visualizers rely heavily on visual characteristics to build mental images, people with aphantasia construct their understanding through other means—semantic knowledge, spatial relationships, or conceptual frameworks.

When answering visual questions, they're attempting to recreate the same cognitive experience they had when originally seeing those objects, but their brains use different tools to rebuild that information. Both approaches involve active construction of visual understanding, just through different neural pathways.

The Individual Variation Revolution

Perhaps most importantly, Liu's research highlights the remarkable diversity of human consciousness.

"During this journey I learned to appreciate the subjective experience of each individual.. Every person has their own internal mental world. They are perceiving the world differently and their brain is doing different strategies to adapt to the world."

Liu's findings reveal something fundamental about consciousness itself that extends far beyond aphantasia. Conscious experience—whether we're seeing something in the real world or imagining it—depends on coordination between different brain networks.

Individual brain regions like high-level visual areas (that process what we see) and frontal-parietal networks (that handle attention and working memory) can function perfectly on their own, but conscious awareness only emerges when these regions successfully communicate with each other.

This principle explains the vast diversity in human subjective experience: differences in how vividly people dream, visualize, or perceive the world all come down to variations in how well these brain networks coordinate their activity.

Looking Forward: Treatment and Understanding

Liu's research opens three important doors for the future.

Potential for intervention: Since people with aphantasia have intact brain regions that simply aren't communicating properly, there's hope that these connections could be strengthened. Unlike conditions where brain tissue is damaged or missing, connectivity problems might be fixable through targeted treatments.

Insights into other conditions: The connectivity disruptions Liu found in aphantasia are similar to patterns seen in other neurodevelopmental differences. This suggests that many variations in human cognition might stem from differences in how brain networks coordinate rather than problems with individual brain areas.

Understanding consciousness itself: Liu's work supports the idea that consciousness doesn't live in any single brain region. Instead, our rich inner experience—mental imagery, sounds, sensations—emerges when multiple brain networks successfully coordinate their activity. When that teamwork breaks down, we lose the subjective experience even though the underlying information remains stored and accessible.

This makes aphantasia a valuable natural experiment for testing theories about how consciousness works and why people have such different subjective experiences of the same world. The research also challenges traditional diagnostic approaches, as Liu's findings about metacognitive deficits raise questions about whether current assessment tools like the VVIQ truly measure reduced imagery or simply reduced confidence in one's responses.

What This Means for Understanding Minds

Liu's research reveals that the aphantasia brain isn't broken or missing crucial components—it's simply accessing the same visual information through different neural routes. The knowledge is there, stored and accessible, just not reaching consciousness in the same way as typical visualizers.

This has profound implications for how we understand consciousness itself. The difference between experiencing a vivid mental image and accessing the same information without imagery might be as simple as whether certain brain networks synchronize their activity.

For people with aphantasia, this research offers both validation and insight. Your brains are performing remarkable feats of information processing, just through different pathways. You're not missing out on information—you're accessing it differently, often with sophisticated strategies developed over a lifetime.

The aphantasia brain has found another path entirely—and that path is teaching us profound truths about the nature of human consciousness itself.