A groundbreaking study by scientists at Georgia State University reveals unexpected insights into the connection between neuron activity and blood flow in deep brain regions. Led by Dr. Javier Stern, the research highlights salt impact on brain function and introduces the concept of “inverse neurovascular coupling.”
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How the Brain Increases Blood Flow to Support Brain Function
When neurons in the brain become active, they usually cause an increase in blood flow to that area. This process, called neurovascular coupling or functional hyperemia, is crucial for proper brain function. It involves the widening of brain blood vessels to supply more oxygen and nutrients to the active neurons. Functional magnetic resonance imaging (fMRI) uses this process to find brain disorders by detecting areas with lower blood flow.
Exploring Deep Brain Regions
Previous studies on neurovascular coupling focused on surface-level brain regions like the cerebral cortex, primarily examining blood flow changes due to external sensory stimuli. However, knowledge about deep brain regions, sensitive to internally generated stimuli (interoceptive signals), remains limited. Dr. Stern’s interdisciplinary team developed an innovative approach combining surgical procedures with advanced neuroimaging techniques to investigate this correlation in deep brain areas, particularly the hypothalamus.
The Hypothalamus and Salt Consumption
Actually, The hypothalamus plays a crucial role in regulating essential bodily functions such as hydration, nutrition, temperature, and reproduction. Published in the journal Cell Reports, the study explored how salt consumption affects hypothalamic blood flow. Dr. Stern explains their choice of salt: “We opted for salt due to the body’s precise need to regulate sodium levels. Specialized cells monitor salt levels in the bloodstream, triggering compensatory mechanisms when we consume salty foods.”
New Findings and Implications of Salt Consumption on Brain Function
Contrary to previous studies showing a positive correlation between neuron activity and increased blood flow, Stern’s team observed reduced blood flow as neurons activated in the hypothalamus. This result, termed “inverse neurovascular coupling,” indicates vasoconstriction leading to hypoxia, a stark contrast to typical cortical responses. In the hypothalamus, vascular reactions to stimuli were diffuse and gradual.
Stern theorizes that hypoxia enhances neurons’ capacity to react to prolonged salt exposure, maintaining activity over extended periods. These findings raise questions about the impact of hypertension on the brain, with approximately 50-60% of hypertension cases thought to be salt-dependent. The research team plans to investigate this mechanism further in animal models to understand its role in salt-induced hypertension and explore its relevance to other brain regions and disorders like depression, obesity, and neurodegenerative diseases.
Future Research and Potential Impacts
Stern remarks, “Consistent intake of high salt levels can lead to hyperactivation of vasopressin neurons, potentially causing excessive hypoxia and brain tissue damage. Understanding this mechanism may help identify new targets to counteract hypoxia-driven activation and improve outcomes for individuals with salt-induced hypertension.”
Reference:
https://www.sciencedaily.com/releases/2021/11/211111154256.htm#:~:text=and%20neurodegenerative%20conditions.-,What%20is%20this%3F,the%20brain%2C%22%20said%20Stern
