The BOLD Fmri Response
The brain is one of the most energy demanding organ in humans. Neurons are characterized by aerobic metabolism (glucose oxidation in aerobic environment) which increases when the neuron is active. In particular, according to hemodynamics response model an increase in neural activity results in different physiological events, being reflected in the BOLD fMRI response: an initial increase in oxygen consumption due to the increased metabolic demand. This increases the concentration of deoxyhaemoglobin and at the same time the concentration of oxyhaemoglobin, resulting in the so called initial ‘spectral dip’ of the BOLD fMRI response and therefore to a small decrease of image intensity. This initial phase is believed to be closely related to neural