Spreading Depolarization
Also written as: SD — Spreading Depolarization
Waves of profound depolarization that propagate across brain tissue, associated with secondary brain injury.
Full Definition
Spreading Depolarization (SD) refers to slowly propagating waves of neuronal and glial depolarization that spread across brain tissue at 2-6 mm/min. These events cause massive ion redistribution, cell swelling, and temporary cessation of electrical activity, followed by a period of hyperemia or oligemia. SDs are increasingly recognized as a mechanism of secondary brain injury in conditions such as stroke, traumatic brain injury, and subarachnoid hemorrhage. Detection requires specialized electrocorticography or intracerebral electrodes, and their presence correlates with worse clinical outcomes and larger infarct volumes.
Usage
Usage note: Distinguish from cortical spreading depression, which refers to the same phenomenon in migraine research.
In Context
- "Electrocorticography revealed multiple spreading depolarizations in the penumbral region following middle cerebral artery occlusion." — Research study report