Two-photon fluorescence microscopy of cerebral hemodynamics

Area of Science:

• Neuroscience
• Physiology
• Biomedical Engineering

Background:

• Neuronal activity and microvascular hemodynamics are closely linked under normal conditions.
• Disruptions in neurovascular coupling are characteristic of many brain diseases.
• In vivo measurement of microvascular hemodynamic responses presents significant challenges.

Purpose of the Study:

• To present a detailed protocol for assessing the hemodynamic response of the cortical microvasculature to neuronal stimulation in vivo.
• To address challenges in maintaining physiological stability and achieving high-resolution imaging of the cerebrovasculature.
• To enable quantitative analysis of brain hemodynamics in response to neural activity.

Main Methods:

• Utilizing two-photon fluorescence microscopy for high-resolution imaging of the intact cortex.
• Developing a surgical protocol for creating a closed cranial window in adolescent rats.
• Implementing rigorous physiological maintenance to ensure a stable systemic state during experiments.
• Performing electrical stimulation of the forepaw to evoke a measurable hemodynamic response.

Main Results:

• Successfully imaged the hemodynamic response of the primary somatosensory cortex microvasculature.
• Demonstrated the feasibility of maintaining physiological stability throughout the imaging process.
• Established a protocol for quantitative analysis of brain hemodynamics using two-photon microscopy.

Conclusions:

• The described protocol enables robust in vivo investigation of neurovascular coupling.
• This method facilitates detailed quantitative analysis of microvascular hemodynamics in response to neuronal activity.
• The findings contribute to a better understanding of brain hemodynamics and its alterations in disease states.