Chris Moore Lecture
Amina Kureshi
Neuroscience Across the Curriculum
Neuroscientist Chris Moore recently gave a talk on Trinity’s campus about his research on the Hemo-Neural Hypothesis. As stated in the paper he co-wrote (Moore & Cao 2008), Moore describes the phenomena of increased localized blood flow to particular areas of the brain hyperemia, and the correlation of hyperemia to local brain activity is termed functional hyperemia. This increase in blood is not due to rising metabolic demands of the cell. We can see how this makes sense since the metabolic cycle of a cell would only increase activity over a longer period of time than it takes to fire the action potential. In order words, if the increase in blood flow was to provide more support for the cell to produce neurotransmitter, which is made in the cell body the slowly transported to the terminal bouton where it can then be released with the occurrence of an action potential, increase in activity would be a delayed response to hyperemia. However, what we see instead is a nearly instantaneous reaction of the neurons/glial cells to the local hyperemia. In fact, part of Moore’s talk discussed a cell that was imaged in his lab, which wraps around the blood vessel. Therefore, when the blood vessel dilates, it is proposed that mechanoreceptoros on the particular neuron cause immediate depolarization. This would theoretically relay information about local hyperemia to other cells. However, a cell need not be wrapped around the blood vessel in order to be affected by local hyperemia. As Moore himself stated, no soma in the brain is more than 30 microns away from a blood vessel. This is such a close proximity that it cannot be imaged with traditional techniques. The technique which allowed for this type of imaging is known as optogenetics, in which a light-sensitive protein is incorporated into the anatomy of genetically altered mice. This protein depolarizes the cells in response to light stimulus.
The greatest lesson to be learned through Moore’s research is that functional hyperemia, while poorly correlated with metabolic demands, is highly correlated with information processing. In layman terms: where the brain is firing is where the blood is going. It is important to note that correlation is not causation; though it may be that the blood flow increases the activity of the neurons/glial cells, it may also be likely that the neurons or astrocytes drive blood flow as a neuromodulator. One proposed mechanisms of interaction between the neural cells/glial cells and blood flow is via the neuromodulator nitric oxide gas, which might easily pass through the blood-brain barrier. Either way, blood acts as a highway to quickly communicate information long distances within the brain and throughout the body.
Chris Moore’s talk brings up many interesting points about how we see communication in the brain. It is important to have speakers like him come and talk at Trinity, as this type of research challenges our current view and context of neuroscience. That said, there were some major points for improvement in the lecture he presented. Moore seemed to jump from topic to topic, from experiment to experiment, glossing over the methods sections or mentioning it as an afterthought. This caused his lecture to lack flow and cohesion. Instead of using his slides to support the main theme of the talk, each slide stood independently of the others. This may have caused confusion for those in the audience. Perhaps the comprehensive lecture given before the common hour talk, which I was unable to attend, was better setup and more well-taught. However the common hour lectures are open to the entire campus and a non-science major who had not read his article would be like a fish out of water if they had only attended the common hour talk. Keeping these points in mind, if these lecture issues could be remedied, I would recommend Chris Moore to come and lecture at Trinity again.
Reference:
Moore, Christopher I., and Rosa Cao. “The Hemo-Neural Hypothesis: On The Role of Blood Flow in Information Processing.” Journal of Neurophysiology 99 (2008): 2035-047. Web
