Summary: Scientists have uncovered how the brains of people with aphantasia, those who cannot visualize mental images, process visual information differently. Although key visual and memory-related brain regions still activate during mental imagery tasks, they show weaker connectivity compared to individuals with typical visualization.
This supports the idea that the richness of mental imagery depends on how well the brain integrates signals across these regions. Despite their lack of internal visuals, aphantasic individuals retain strong visual knowledge, showing that mental imagery isn’t necessary for understanding or creativity.
Key Facts:
- Aphantasia Defined: About 4% of people are unable to voluntarily visualize mental images.
- Neural Connectivity: Aphantasic individuals activate similar brain areas during imagery tasks but with weaker network integration.
- Functional Insight: Mental imagery quality depends on connectivity between attention, memory, and visual regions—not just activation alone.
Source: Paris Brain Institute
Thanks to 7T fMRI, researchers from Paris Brain Institute and NeuroSpin, the CEA’s neuroimaging centre, are exploring the neural substrate of visual imagery at very high resolution for the first time.
Their results, published in Cortex, pave the way for a better understanding of this fascinating cognitive ability, which some of us entirely lack.
Visual imagery—the ability to mentally summon the image of a landscape, a person, or an object that is not directly observable—varies greatly in intensity from one individual to another.
Some people can recall a detailed city map and walk through each street as if watching a movie. Thinking of a loved one, others may barely make out their silhouette and hair color.
Interestingly, about 4% of the population seems completely unable to visualize a scene on demand: this is known as aphantasia, a cognitive peculiarity known for over a century but only recently studied by scientists.
Preliminary studies suggest that aphantasia is present from birth and often affects multiple members of the same family. While it is not considered a disorder, it is frequently associated with a weaker-than-average autobiographical memory, difficulty recognizing faces, or even autism spectrum disorder. However, these associations remain uncertain and hard to explain.
To understand what characterizes aphantasia at the brain level, we needed to study the neural mechanisms involved in visual imagery and perception. For this, we took advantage of 7-Tesla fMRI, which allows us to observe brain activity at extremely high resolution,” said Paolo BARTOLOMEO Inserm, co-leader of the PICNIC team at Paris Brain InstituteMRI Scans of Inner Images.
Most previous studies on aphantasia relied on highly subjective tests in which participants had to self-evaluate their visualization abilities. Under such conditions, it’s difficult to determine whether these tests actually assess mental imagery or instead reflect metacognition, that is, a person’s ability to describe their own mental processes.
In collaboration with Stanislas Dehaene’s team at NeuroSpin, the CEA’s brain imaging center, postdoctoral researcher Jianghao Liu, Paolo Bartolomeo, and their colleagues sought to examine the characteristics of aphantasic individuals more objectively.
“We wanted to identify the precise neural circuits involved in mental imagery and visual perception. Most importantly, we aimed to understand how visual information is processed in the brain in the absence of visual stimuli,” said Jianghao LIU Postdoctoral researcher.
Visualizing a scene with the “mind’s eye” is cognitively complex. It involves experiencing an object’s visual properties without the object being present. This process not only recruits brain circuits linked to sensory experience but also draws on language and memory.
To break down this process, the researchers recruited 10 aphantasic subjects and 10 subjects with “typical” mental imagery. These individuals underwent ultra-high-field functional MRI while responding, from memory, to questions about the visual features of familiar objects, words, faces, and places.A Connectivity Deficit?
The study found that attempting mental visualization activates fronto-parietal networks, which are important for attention, awareness, and working memory, as well as the left fusiform gyrus, located on the underside of the temporal lobe. It also activates areas of the ventral temporal cortex involved in letter recognition, face perception, and color processing.
Among aphantasic individuals—even if they report no experience of mental imagery—these same regions were also activated, but with reduced functional connectivity. In other words, these areas communicated less efficiently than in people with typical mental imagery.
These preliminary findings support a hypothesis already considered by researchers: the quality of visual experience, whether based on perception or imagination, depends on how well information is integrated between fronto-parietal networks and visual perception networks. The left prefrontal cortex might play a causal role in the awareness of these visual experiences.
“This might explain why aphantasic people still retain accurate visual knowledge of objects. For example, they clearly remember that spinach is a darker green than lettuce,” Liu notes.
Future studies will help determine whether aphantasia manifests in the same way for all affected individuals or whether there are subtypes linked to different causes.
In addition to highlighting the extreme variability in how we experience the world, research on aphantasia shows that mental imagery is not a prerequisite for reasoning, imagination, conceptualization, or creativity. Ultimately, these studies may illuminate the relationships between mental imagery, perception, memory, and neurodevelopment.
Funding: This study was funded by Dassault Systèmes.
About this aphantasia research news
Author: Paolo Bartolomeo
Source: Paris Brain Institute
Contact: Paolo Bartolomeo – Paris Brain Institute
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Lives without imagery – Congenital aphantasia” by Jianghao Liu et al. Cortex
Open access.
“Frontoparietal asymmetries leading to conscious perception” by Jianghao Liu et al. Trends in Cognitive Sciences
Abstract
Lives without imagery – Congenital aphantasia
Visual imagery is, for most of us, a conspicuous ingredient of everyday experience, playing a prominent role in memory, daydreaming and creativity. Galton, who pioneered the quantitative study of visual imagery with his famous ‘breakfast-table survey’, reported a wide variation in its subjective vividness (Galton, 1880).
Indeed, some participants described ‘no power of visualising’. This phenomenon has received little attention since, though Faw reported that 2.1–2.7% of 2,500 participants ‘claim no visual imagination’ (Faw, 2009).
The experience of voluntary imagery is associated with activity in fronto-parietal ‘executive’ systems and in posterior brain regions which together enable us to generate images on the basis of our stored knowledge of appearances (Bartolomeo, 2008). The relative contributions of lower and higher order visual regions to the experience of visual imagery are debated (Bartolomeo, 2008).
Clinical reports suggest the existence of two major types of neurogenic visual imagery impairment: i) visual memory disorders, causing both visual agnosia and imagery loss, and ii) ‘imagery generation’ deficits selectively disabling imagery (Farah, 1984).
In 2010 we reported a particularly ‘pure’ case of imagery generation disorder, in a 65 year old man who became unable to summon images to the mind’s eye after coronary angioplasty (Zeman et al., 2010).
Following a popular description of our paper (Zimmer, 2010), we were contacted by over twenty individuals who recognised themselves in the article’s account of ‘blind imagination’, with the important difference that their imagery impairment had been lifelong.
Here we describe the features of their condition, elicited by a questionnaire, and suggest a name – aphantasia – for this poorly recognised phenomenon.
Abstract
Frontoparietal asymmetries leading to conscious perception
Recent human intracerebral recordings reveal that frontoparietal circuits linked by the superior longitudinal fasciculus (SLF) have critical, hemisphere-asymmetric contributions to conscious perception.
Right-hemisphere networks are crucial for attention-based prioritization of information; left-hemisphere regions contribute to perceptual decisions and model building. These asymmetries confirm and specify clinical evidence from neglect patients.
