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The Architect Who Lost the Ability to Imagine: The Cerebral Basis of Visual Imagery

DOI: 10.3390/brainsci10020059
Thorudottir, S., Sigurdardottir, H. M., Rice, G. E., Kerry, S. J., Robotham, R. J., Leff, A. P., & Starrfelt, R. (2020). The architect who lost the ability to imagine: the cerebral basis of visual imagery. Brain Sciences, 10(2), 59. doi:10.3390/brainsci10020059

Abstract

While the loss of mental imagery following brain lesions was first described more than a century ago, the key cerebral areas involved remain elusive. Here we report neuropsychological data from an architect (PL518) who lost his ability for visual imagery following a bilateral posterior cerebral artery (PCA) stroke. We compare his profile to three other patients with bilateral PCA stroke and another architect with a large PCA lesion confined to the right hemisphere. We also compare structural images of their lesions, aiming to delineate cerebral areas selectively lesioned in acquired aphantasia. When comparing the neuropsychological profile and structural magnetic resonance imaging (MRI) for the aphantasic architect PL518 to patients with either a comparable background (an architect) or bilateral PCA lesions, we find: (1) there is a large overlap of cognitive deficits between patients, with the very notable exception of aphantasia which only occurs in PL518, and (2) there is large overlap of the patients’ lesions. The only areas of selective lesion in PL518 is a small patch in the left fusiform gyrus as well as part of the right lingual gyrus. We suggest that these areas, and perhaps in particular the region in the left fusiform gyrus, play an important role in the cerebral network involved in visual imagery.

Authors

  • Sandra Thorudottir2
  • Heida Maria Sigurdardottir3
  • Grace E. Rice1
  • Sheila J. Kerry1
  • Ro J. Robotham1
  • Alex P. Leff2
  • Randi Starrfelt1

What This Study Is About

Researchers wanted to find the specific "engine room" in the brain that creates mental imagery—the ability to picture things in your mind. They did this by studying a professional architect who suddenly lost his "mind's eye" after a stroke.

How They Studied It

The team focused on one man (known as PL518) who developed aphantasia—the inability to visualize—after a brain injury. To find out why he lost this skill while others didn't, they compared him to four other patients who had similar strokes but could still visualize perfectly. Everyone took tests on memory and face recognition, filled out imagery questionnaires, and had high-tech brain scans (MRIs) to map exactly where their brains were damaged.

What They Found

The researchers played a high-stakes game of "spot the difference" with the brain scans. They found that while all the patients had similar injuries, the architect had damage in two very specific spots that the others didn't: a small patch in the left fusiform gyrus and part of the right lingual gyrus.
Even though the architect could no longer "see" a square or a circle in his head, he could still describe them using facts. It’s like his brain’s "graphics card" was broken, but his "hard drive" full of information was still working fine.

What This Might Mean

This suggests that these specific areas in the back of the brain are the "on-switches" for mental pictures. However, because this was a "case report" (a study of just a few specific people), we have to be careful. It *suggests* these areas are vital for imagery, but it doesn't *prove* they work the same way for everyone. Brains are complex, and different people might use different "circuits" to visualize.

One Interesting Detail

Before his stroke, the architect was a "super-visualizer." He described his old ability to mentally rotate 3D buildings as "pretty impressive." After the stroke, he said trying to imagine something as simple as an elephant was "almost painful" because he could only think of the *concept* of the animal, not the actual image.
This summary was generated by AI and may contain errors. Always refer to the original paper for accuracy.