Changes in neurovascular coupling with cerebral perfusion pressure indicate a link to cerebral autoregulation

Cerebral autoregulation ensures continuous blood supply to brain tissue despite changes in cerebral perfusion pressure (CPP). Neurovascular coupling, the spatial and temporal relationship between neurons and the vasculature, relies on sufficient blood flow to meet neuronal demands during activation. These mechanisms break down in pathological situations, such as traumatic brain injury, hydrocephalus, and stroke, where extreme levels of CPP can cause dysregulation in cerebral blood flow. Here, we experimentally tested the influence of cerebral autoregulatory impairment on neurovascular coupling by altering CPP in a hydrocephalus-like animal model. We recorded local neural and vascular evoked responses to visual stimuli, non-invasively, using electroencephalography (EEG) and near-infrared spectroscopy (NIRS). Both, evoked neural and vascular responses, show changes with CPP. We also studied the coupling between these evoked responses by evaluating a hemodynamic response function (HRF). We found that the HRF shape changes with CPP and shows neurovascular coupling alterations linked to the state of autoregulatory health. Our study provides preliminary experimental evidence on the effect of cerebral dysregulation on neurovascular coupling, relating two cerebral phenomena that can be leveraged to improve patient prognosis in cerebral pathologies.