BrainGlutamic AcidAmino AcidsOptical ImagingPositron-Emission TomographyMagnetic Resonance SpectroscopyBloodBloodHumansOxygenNeuronsNeuronsNeurogliaNeurogliabody weightCarbon DioxideMetabolismEyeEyeRetinaPPPDE1Adenosine TriphosphateRatsGlucoseMammalsGlutamate 6AtpResonance Spectroscopy ( Mrs. ) TechniqueNeurophysiological TechniqueSingle Photon Emission Tomography ( Spect )Various Optical Image TechniquePositron Emission Tomography ( Pet )Functional Magnetic ResonanceGlutamateAmino Acid GlutamateNormal BrainHumanModern Functional BrainNeuronGlial CellCellDiseaseRatOngoing OxygenArterial OxygenAvailable OxygenPostsynaptic IonMammalianbrain 's energybrain activityblood flowneuronal activityfMRIPetactivationoxygen consumptionOEFuniformityspatial uniformityongoing metabolic activityhuman brainbrain activationmetabolic activitytransient changebrain functionglutamateanesthetized ratMrs.neuronfluxcortexmetabolic activity of the brainbaselinebaseline activityongoing activityanesthesialevel of anesthesiastimulationspikespike frequencybrain oxygen consumptioncerebral cortex of the anesthetized ratextracellular recordextracellular record of neuronal activityresonancePNAS 4conceptualization of the instantiation of functional processfunction of the human brainneurophysiological techniquecellular activitymetabolismbrain energy metabolismimportant new informationbrain 's metabolismoptical image techniquetomographyphoton emission tomographysingle photon emission tomographylive human brainfunction of the live human brainmodern image techniqueincrease use of modern image techniqueongoing functional processbrain 's large energy budgethigh rate of metabolismbrain accountaverage adult humanbudgetbrainoxygenconsumptionrefneuronalfractionmeasurementglialneurotransmitterMrs. measurementsomatosensory stimulationbrain 's primary excitatory transmitterexcitatory amino acid glutamateflux of the excitatory amino acid glutamateextant informationuniversity 4motoricmotoric activity 2