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Loss of imagery phenomenology with intact visuo-spatial task performance: A case of ‘blind imagination’

DOI: 10.1016/j.neuropsychologia.2009.08.024
Zeman, A. Z., Della Sala, S., Torrens, L. A., Gountouna, V.-E., McGonigle, D. J., & Logie, R. H. (2010). Loss of imagery phenomenology with intact visuo-spatial task performance: a case of ‘blind imagination’. Neuropsychologia, 48(1), 145–155. doi:10.1016/j.neuropsychologia.2009.08.024

Abstract

This study focuses on the case of a patient, MX, who lost the ability to generate visual images but performed normally on standard tests of perception, visual imagery, and memory. The researchers used functional MRI scanning to explore this unexpected phenomenon and found that while MX's brain showed reduced activity in posterior regions during attempted imagery, activity in frontal regions was increased compared to controls. These findings suggest that MX adopted a different cognitive strategy when performing the imagery task, which led to successful performance in visual memory and imagery tasks without the experience of visual imagery. The results of this study demonstrate the dissociation between the phenomenal experience of visual imagery and successful performance in visual memory and imagery tasks.

Authors

  • Adam Zeman14
  • Sergio Della Sala4
  • Lorna A. Torrens1
  • Viktoria-Eleni Gountouna1
  • David J. McGonigle1
  • Robert H. Logie1

Overview/Introduction

This study explores a fascinating case of a patient, referred to as MX, who lost the ability to generate visual images but continued to perform normally on tests related to perception, visual imagery, and memory. This unusual situation prompted researchers to investigate how MX could maintain normal performance levels despite the absence of visual imagery. Using advanced brain imaging techniques, the study reveals how MX's brain activity differed from that of typical individuals during tasks involving visual imagery.

Methodology

  • Participants: MX, a 65-year-old retired surveyor, was compared to 10 healthy individuals of similar age and background.
  • Techniques Used: Functional MRI (fMRI) was employed to observe brain activity during tasks requiring visual imagery.
  • Tasks: Participants were asked to view and imagine famous faces. Control tasks involved scrambled images and nonsense letter strings to ensure that any differences were due to imagery and not perception.

Key Findings

  • Brain Activity: While MX's brain activity was similar to controls when viewing faces, it differed significantly during imagery tasks. MX showed reduced activity in the posterior brain regions but increased activity in the frontal regions.
  • Cognitive Strategy: MX appeared to use a different cognitive strategy to perform imagery tasks successfully, relying less on visual imagery and more on alternative methods.
  • Performance: Despite his inability to visualize, MX performed normally on visual memory and imagery tasks, suggesting that visual imagery is not essential for success in these areas.

Implications

  • Understanding Visual Imagery: This study challenges the assumption that visual imagery is necessary for performing tasks that typically rely on it. It highlights the brain's adaptability and the potential for alternative cognitive strategies.
  • Applications in Cognitive Neuroscience: These findings could influence approaches in cognitive rehabilitation, suggesting that individuals with impairments in visual imagery might benefit from training in alternative strategies.

Limitations

  • Single Case Study: As this research focuses on a single individual, the findings may not be generalizable to all cases of imagery loss.
  • Underlying Causes: The exact neurological reasons for MX's condition remain unclear, and further research is needed to understand the mechanisms behind such dissociations.
In summary, this study provides valuable insights into the complex nature of visual imagery and cognition, demonstrating that successful task performance can occur even in the absence of conscious visual imagery.