Hi, I was wondering if changes in stroke volume or cardiac output etc affect BOLD? It seems to make sense that they would, but I haven’t seen any data on it. Would appreciate any direction, even if speculation. Thank you! @CesarCaballeroGaudes @smoia
1 Like
Hi @sheila, Can you be a little bit more specific about your question? And what type of stroke you are referring to? Stroke will definitely affect the BOLD signal as it affects cerebral blood flow and alters the neurovascular coupling, but how depends on the question you want to address.
Hi @CesarCaballeroGaudes I was also confused about this. She’s referring to stroke volume, “the volume of blood pumped from the ventricle per beat.” I know that heart rate is an important confound in BOLD signal, but I hadn’t ever thought of other features of cardiac physiology, like the ones @sheila listed.
Hi! Thank you for responding @CesarCaballeroGaudes ! Sorry, I should have clarified— I’m not asking about strokes/CVAs. By stroke volume, I mean the amount of blood ejected from the left ventricle with each heart beat. And for cardiac output, I mean the stroke volume * heart rate. Basically I’m wondering if, in a given person, you do something that acutely/temporarily drops cardiac output by like 30%, would this lower amount of blood leaving the heart affect BOLD even if someone does not report symptoms of lightheadedness, dizziness, diaphoresis etc. My understanding is that most people can tolerate this acutely lower cardiac output without symptoms because of reflex increases in systemic vascular resistance (and the increased heart rate built into the calculation of cardiac output). But I’m wondering if there are sub-symptomatic/sub-threshold changes blood reaching the brain that impact BOLD from the decreased cardiac output, or if increased systemic vascular resistance can 100% “make up for” the lower cardiac output in most individuals? I’m not trying to isolate/demonstrate a consistent effect, but more so wondering if it’s a confound in certain situations.
Hello @sheila @tsalo, I’m not really familiar with this topic. However, I found these two papers that might be relevant:
https://www.sciencedirect.com/science/article/pii/S1053811922004128
https://doi.org/10.1177/0271678X241298588
Hope they are helpful,
César
No worries! This is still reassuring that I’m not missing something major that most people already know about. Thank you so much for sending those papers @CesarCaballeroGaudes !!