14 DAY TRIAL // 'Thinking with the heart' and 'hot blooded' can get a new real meaning now. Besides, ancient Greeks, like Aristotle, were convinced that the circulatory system dictates thoughts and emotions.
The new Hemo-Neural Hypothesis, brought forth by a team led by Christopher Moore, a principle investigator in the McGovern Institute for Brain Research at MIT and an assistant professor in MIT's Department of Brain and Cognitive Sciences, states that blood is not just a food and oxygen supplier for neurons, but actually shapes the brain activity.
"We hypothesize that blood actively modulates how neurons process information. Many lines of evidence suggest that blood does something more interesting than just delivering supplies. If it does modulate how neurons relay signals, that changes how we think the brain works." said Moore.
Punctual shifts in blood flow would model the activity of close neurons, changing the signals they pass to each other and tuning data flow throughout the brain. This affirmation is based on ongoing researches made in Moore's laboratory. This could change our knowledge on Alzheimer's, schizophrenia, multiple sclerosis and epilepsy.
"Many neurological and psychiatric diseases have associated changes in the vasculature. Most people assume the symptoms of these diseases are a secondary consequence of damage to the neurons. But we propose that they may also be a causative factor in the disease process, and that insight suggests entirely new treatments." said Moore.
Epileptic people often display abnormal blood vessels in the brain area linked to seizures and the new hypothesis says that the abnormal flow could provoke epileptic attacks. Thus, chemicals targeting blood flow could come as an alternative to current cures.
The novel idea also changes the importance of functional magnetic resonance imaging (fMRI).
"Scientists looking at fMRI currently regard blood flow and volume changes as a secondary process that only provides read-out of neural activity. If blood flow shapes neural activity and behavior, then fMRI is actually imaging a key contributor to information processing." said co-author Rosa Cao, a graduate student in Moore's lab.
Investigations led in Moore's lab match this supposition. fMRI researches made on the sensory homunculus (brain's map of body parts like fingers, toes and limbs) found that increased blood flows to the fingertip area made people perceive more rapidly a light tap on the finger.
The new hypothesis does not oppose prior knowledge. In fact, it fits perfectly and comes with a more detailed interpretation, enhancing fMRI's role.
The team tries to explain these effects on diffusible factors that could pass out of vessels, changing neural activity and blood volume changes could influence their levels. Neurons and support glia cells could also be affected by the mechanics of the expanding/contracting blood vessels. Blood flow also influences the brain's temperature, directly linked to neural activity.