Maret, G. | Search bioRxiv

bioRxiv2018

Cerebral blood flow measured with diffusing wave spectroscopy during anesthesia

The adequate perfusion of the brain is of utmost importance where already short periods of hypoperfusion may lead to permanent damage. In order to increase patient safety the cerebral blood flow should be monitored in clinical settings during situations, such as anesthesia, where the perfusion might be disturbed. The cerebral blood flow is however not monitored on a routine basis during anesthesia. Diffusing wave spectroscopy is a relative novel optical method that non-invasively measures changes in cerebral blood flow. Here we report changes in cerebral blood flow associated with a delayed cardiac output, a change in isoflurane concentration and body temperature observed during general anesthesia with isoflurane in pigeons.

biophysics↗

bioRxiv2018

3D Functional Ultrasound Imaging of Pigeons

Recent advances in ultrasound Doppler imaging have allowed to visualize brain activity in small mammalian species such as rats and mice. In birds, this type of functional ultrasound imaging was impossible up to now because birds have physiological characteristics that are unfavorable for current functional ultrasound acquisition schemes. Here, we introduce a high-definition functional ultrasound acquisition method (HDfUS) acquiring 20,000 frames per second continuously. This enabled first successful functional studies on awake pigeons subjected to auditory and visual stimulation. We show that the improved spatiotemporal resolution and sensitivity of HDfUS allows to visualize and investigate the temporally resolved 3D neural activity evoked by a complex stimulation pattern, such as a moving light source. This illustrates the enormous potential of HDfUS imaging to become a new standard functional brain imaging method revealing unknown, stimulus related hemodynamics at excellent signal-to-noise ratio and spatiotemporal resolution.

neuroscience↗