Applications

Spreading Cortical Depression

Cortical spreading depolarization (CSD) describes a wave of neuronal depolarization associated with influx of cat-ions and water which blocks normal cerebral activity. CSD induces changes to microvascular tone with the vasoconstriction phase (Cortical Spreading Ischemia, CSI) there is associated risk of progressive damage.

Laser Doppler Monitoring

With LD monitoring, the CSD wave can be assessed by observing its transit at a single point. These measurements can be made with the moorVMS-LDF and needle probes (e.g. VP3 or VP4) held in position by micromanipulator or by using a wet-stick probe holder at the probe tip (PHN-WS) or a wet-stick, disposable single fibre probe, P10k or a disposable single fibre held in place with a PHDO holder bonded to the tissue.

Laser Doppler Imaging

Flux changes can also be observed by laser Doppler Imaging and laser speckle imaging. The waves move relatively slowly and experimental areas of the cerebral cortex are relatively small so the scan duration of a high resolution (100µm/pixel) LDI (moorLDI2-HR) is acceptable. For higher resolution (10µm/pixel) and greater speed, speckle imaging with moorFLPI, operating in temporal mode, is recommended. To aid imaging stability and manipulation, the moorLDI2-HR should be mounted on a DS2 desktop stand; the moorFLPI should be mounted on a moorFLPI-microstand.

Related Investigations

Separate information is given on clinical assessments of Cerebral Ischaemia and MCA Occlusion (Stroke Model).

Anaesthesia choice has been found by Wang et al (2010) to have a significant impact on cerebral auto-regulation; their investigation found that auto-regulation of cerebral tissue blood flow, assessed by moorFLPI, was preserved with Ethomidate down to about 27mmHg MAP whereas with several other anaesthetics, cerebral auto-regulation was abolished and a linear relationship between cerebral tissue blood flow and MAP was observed.

Experiments have shown that the mice skulls (kept wet with artificial cerebrospinal fluid or 0.9% saline warmed to 37°C) were sufficiently transparent to enable moorFLPI measurements without significant loss of blood flow signal. For the analysis, regions of interest were chosen that excluded major blood vessels.

References

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