Hemo-Neural Hypothesis

The Hemo-Neural hypothesis states that blood flow to cerebral areas is inextricably linked to neural activity. Unlike current dogma that interprets blood oxygen level dependent (BOLD) signals of functional magnetic resonance imaging (fMRI) as completely metabolic signals, the Hemo-Neural hypothesis claims that the blood flow may be interacting with neurons on a fundamental level.

The Hemo-Neural hypothesis has been presented publicly by Christopher Moore, an assistant professor of MIT's McGovern Institute. Moore argues that, though a given artery supplies a fairly large piece of a cortical surface (as compared with the relative size of a neuron), there is a finer resolution that can be afforded to show that the interaction of blood and the cortical patch is substantially more subtly tuned than is currently thought. Thus within a section of global blood flow, there may be highly specific concentrations that target specific neuronal activity in a way that affects the properties of the neurons.

Moore cites interesting and unexplained features such as stretch receptor K⁺ channels in dense populations in cortical neurons that he postulates may play a role in sensing the changing extracellular environment due to an increased hemodynamic response. This hypothesis has not been tested.

Preliminary and unpublished data from his own lab has suggested that blood flow to a region of the brain may, in fact, have a regulatory effect on neural activity in the form of inhibition, which promotes its traditionally assumed role of metabolic function.

However such a hypothesis is very controversial, and more data will be required to substantiate or negate it.

Reference: http://jn.physiology.org/cgi/content/abstract/01366.2006v1