Related Experiment Video
Updated: Jun 17, 2026

Stimulus-specific Cortical Visual Evoked Potential Morphological Patterns
Published on: May 12, 2019
Anatomical correlate of positive spontaneous visual phenomena: a voxelwise lesion study
B Baier1, B de Haan, N Mueller
1Department of Neurology, University of Mainz, Langenbeckstr. 1, 55131 Mainz, Germany. baierb@uni-mainz.de
Objectives:
Visual phenomena such as phosphenes, photopsias, or complex visual hallucinations occur in patients with lesions affecting the occipital, parietal, or temporal lobe. Whether these phenomena are provoked by lesions in specific anatomical regions is still uncertain. To determine which brain regions might be involved in such visual phenomena, we used new brain imaging and lesion analysis tools that allow a direct comparison with control patients.
Methods:
Visual phenomena were investigated in a total of 23 patients with acute infarctions along the visual pathways (6 patients with left-sided and 17 patients with right-sided lesions).
Results:
Ten of these 23 patients (43%) reported positive spontaneous visual phenomena (PSVP). Nine of the 10 patients (90%) with PSVP reported phosphenes; only 3 of the 10 (30%) reported photopsias. Statistical voxelwise lesion-behavior mapping revealed that the areas specifically related to PSVP are V1, V2, and the optic radiation.
Conclusions:
Disinhibition of earlier visual areas after lesions of the visual cortex and its afferent fibers seems to be the crucial mechanism in the genesis of visual phenomena in acute stroke patients.
Related Concept Videos
Brain Imaging
These technologies include computerized axial tomography (CAT or CT scans), positron-emission tomography (PET scans), magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), and Transcranial Magnetic Stimulation (TMS).
Visual Agnosia
Imaging Studies IV: Magnetic Resonance Imaging
Positron Emission Tomography
One of the main requirements of a PET scan is a positron-emitting radioisotope, which is produced in a cyclotron and then attached to a substance used by the part of the body being...
Imaging Studies II: Positron Emission Tomography and Scintigraphy
Fundamental Principles of PET
Imaging Studies VII: Vascular Imaging

