Video 2. Spreading depression and migraine
Spreading depression is the likely cause for migraine aura and pain. It is found in normal brain and shown here triggered in a brain slice (gray) by an electrical pulse (red posts to the lower right) and recorded by the electrode to the left to illustrate the basic components and how they relate to migraine aura. Normal electrical activity of brain is seen as small vertical deflections in white line (1). Then with the onset of spreading depression, this activity often increases (2), which likely presents the visual obscuration (flashing lights, etc) of the aura (see video 1). Next when the increased activity is sufficiently coordinated, spreading depression is triggered (3), which briefly stops all brain activity in that area (4) before returning to normal (visual loss (scotoma) of the aura). Importantly, spreading depression (migraine) is triggered by a loss of brain cell inhibition and consists of a complete loss of brain activity (that is seen here as a large DC negative potential) that propagates (at 3 millimeters/minute) across brain. This is the only event of brain that moves this slowly. The movement is shown in video 3. (This video was created with the assistance of Mr. Dale Mertes from the University of Chicago.)
Tags: Migraine, brain slice, Spreading, brain activity, brain cell, Depression, video
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Interesting perspective and thought! I think you idea fits the functional changes that occur with increased excitability and spreading depression though deciphering a functional utility for the “adaptive” resposne requires some thoguht. As a first conclusion, I’d have to say it seems like it would be a “maladaptive” response.
Could spreading depression be understood as an adaptive response to counteract the escalating electrical activity that immediately precedes it? i.e., is it a sort of built-in fail-safe?