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Bibliographic Details
Main Author:	Vergucht, Maarten
Format:	Recurso digital
Language:	English
Published:	Zenodo 2026
Subjects:	scintillating scotoma double dissociation amaurosis fugax transmission theory filtertheory of consciousness cortical ischemia carotid artery stenosis spreading depolarisation neural correlates of consciousness migraine aura visual phenomenlolgy hard problem of consciousness
Online Access:	https://doi.org/10.5281/zenodo.19421752
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During a migraine aura, patients experience a scintillating scotoma: sparkling, brilliant white light with vivid spectral colours that expands across the visual field. This luminous experience is often described as beautiful and awe-inspiring. The conventional production model claims that cortical spreading depression (CSD) produces this light through spontaneous excitation in the visual cortex. However, this explanation suffers from a profound internal inconsistency. Extensive clinical evidence demonstrates that CSD consistently produces functional deficits (loss of function) wherever it travels: hemiparesis in the motor cortex, paresthesia in the somatosensory cortex, and aphasia in language areas. It is illogical to posit that CSD produces functional loss everywhere except in the visual cortex, where it supposedly produces a gain of function (brilliant light). The logically consistent interpretation is that CSD causes functional failure in the visual cortex as well, and this sparkling, brilliant inner light appears as a result of this cortical silence. Two independent lines of neurophysiological evidence confirm this profound suppression: • MEG Evidence: During scintillating scotoma, alpha-band power undergoes profound desynchronization—a near-complete suppression of power—for the duration of the scintillations, while gamma-band power likewise decreases. The brain is falling silent. • VEP Evidence: Visually evoked potentials (VEPs)—the cortex's measurable electrical response to external light—are suppressed or completely abolished, as demonstrated by MacLean et al. (1975) and confirmed by Nyrke et al. (1990). The cortex does not respond to light from the outside world, yet the patient perceives brilliant inner light. Further key findings include: • Rebutting the "Wavefront" Argument: The scintillations precisely track the sustained depression phase of CSD (5-30 minutes), not the brief depolarisation burst at the wavefront (seconds). Furthermore, chronic ischemia patients experience continuous scintillations for weeks without any propagating wavefront. • Terminal Spreading Depolarisation (TSD): TSD is the intense, permanent version of CSD that occurs at death. The natural extrapolation along this continuum is that more cortical silence corresponds to more luminous experience, not less. The burden of proof falls on the production model to explain why this empirically established inverse correlation would suddenly reverse at the severe end. • Double Dissociation: Retinal ischemia (eye fails, cortex intact) leads to darkness, while cortical ischemia (cortex fails, eye intact) leads to brilliant light. The production model predicts darkness in both cases. Only the filter theory correctly predicts both outcomes. If this brilliant light correlates with the absence of neural activity rather than its presence, it has no neural correlate. It is not produced by the brain. It is revealed by the brain's silence. Ultimately, a profound contrast emerges: physical, external light that is blocked results in darkness, whereas inner, non-physical light increases when cortical depression sets in. These two phenomena appear to be mutually exclusive. The perception of physical light precludes the experience of non-physical light, and the emergence of non-physical light requires the exclusion of physical light. When the brain falls silent to the outside world, the brilliant light within appears.

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