Neurovascular Coupling

AbstractThe spatial-temporal sequence of cerebral blood flow (CBF), cerebral blood volume (CBV) and blood velocity changes triggered by neuronal activation is critical for understanding functional brain imaging. This sequence follows a stereotypic pattern of changes across different zones of the vasculature in the olfactory bulb, the first relay of olfaction. However, in the cerebral cortex, where most human brain mapping studies are performed, the timing of activity evoked vascular events remains controversial. Here we utilized a single whisker stimulation model to map out functional hyperemia along vascular arbours from layer II/III to the surface of primary somatosensory cortex, in anesthetized and awake Thy1-GCaMP6 mice. We demonstrate that sensory stimulation triggers an increase in blood velocity within the mid-capillary bed and a dilation of upstream large capillaries, and the penetrating and pial arterioles. We report that under physiological stimulation, response onset times are highly variable across compartments of different vascular arbours. Furthermore, generating transfer functions (TFs) between neuronal Ca2+ and vascular dynamics across different brain states demonstrates that anesthesia decelerates neurovascular coupling (NVC). This spatial-temporal pattern of vascular events demonstrates functional diversity not only between different brain regions but also at the level of different vascular arbours within supragranular layers of the cerebral cortex.

Download Full-text

Anomalous neurovascular coupling in patients with generalized anxiety disorder evaluated by combining cerebral blood flow and functional connectivity strength

Progress in Neuro-Psychopharmacology and Biological Psychiatry ◽

10.1016/j.pnpbp.2021.110379 ◽

2021 ◽

pp. 110379

Author(s):

Yuyan Chen ◽

Qian Cui ◽

Wei Sheng ◽

Qin Tang ◽

Fengmei Lu ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Anxiety Disorder ◽

Functional Connectivity ◽

Generalized Anxiety Disorder ◽

Neurovascular Coupling ◽

Generalized Anxiety ◽

Functional Connectivity Strength ◽

Connectivity Strength

Download Full-text

Neurovascular coupling during optogenetic functional activation: Local and remote stimulus-response characteristics, and uncoupling by spreading depression

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x19845934 ◽

2019 ◽

Vol 40 (4) ◽

pp. 808-822 ◽

Cited By ~ 4

Author(s):

Maximilian Böhm ◽

David Y Chung ◽

Carlos A Gómez ◽

Tao Qin ◽

Tsubasa Takizawa ◽

...

Keyword(s):

Minimally Invasive ◽

Spreading Depression ◽

Barrel Cortex ◽

Disease Process ◽

Neurovascular Coupling ◽

Laser Speckle ◽

Cortical Activation ◽

Somatosensory Stimulation ◽

Response Characteristics ◽

Electrophysiological Activity

Neurovascular coupling is a fundamental response that links activity to perfusion. Traditional paradigms of neurovascular coupling utilize somatosensory stimulation to activate the primary sensory cortex through subcortical relays. Therefore, examination of neurovascular coupling in disease models can be confounded if the disease process affects these multisynaptic pathways. Optogenetic stimulation is an alternative to directly activate neurons, bypassing the subcortical relays. We employed minimally invasive optogenetic cortical activation through intact skull in Thy1-channelrhodopsin-2 transgenic mice, examined the blood flow changes using laser speckle imaging, and related these to evoked electrophysiological activity. Our data show that optogenetic activation of barrel cortex triggers intensity- and frequency-dependent hyperemia both locally within the barrel cortex (>50% CBF increase), and remotely within the ipsilateral motor cortex (>30% CBF increase). Intriguingly, activation of the barrel cortex causes a small (∼10%) but reproducible hypoperfusion within the contralateral barrel cortex, electrophysiologically linked to transhemispheric inhibition. Cortical spreading depression, known to cause neurovascular uncoupling, diminishes optogenetic hyperemia by more than 50% for up to an hour despite rapid recovery of evoked electrophysiological activity, recapitulating a unique feature of physiological neurovascular coupling. Altogether, these data establish a minimally invasive paradigm to investigate neurovascular coupling for longitudinal characterization of cerebrovascular pathologies.

Download Full-text