Schematic drawing of the TRN-modulated thalamocortical looping model of conscious awareness. THL: thalamus, V1: the primary visual cortex. As the color of processing-flow lines gets darker (from yellow to orange, and finally to red), more elaborated information processing is being produced by means of iterating thalamocortical loops through the TRN. Cortical networks tie together neuronal assemblies in widespread cortical regions, and the TRN may play a central role in organizing all of the networks. (for details, click to link)

Schematic diagram of brain signal detection mechanisms. EEG measures the electrical potential differences on the scalp that are generated by cortical neural activity. The ensembles of neurons transmitting neurological signals across their synapses act as dipole sources. MEG detects the magnetic fields associated with such neuronal activation by SQUID sensors. fMRI measures the hemodynamic responses (particularly magnetic dynamics of protons depicted as ‘H’) related to neural activity. Its technique is principally based on the detection of local BOLD signal contrast during neuronal activation using susceptibility-weighted MR sequences. fTCD is based on ultrasound Doppler imaging, developed to measure the velocity of blood flow in major cerebral arteries by the ultrasound transducer (abbreviated as ‘UST’). Using multiple arrays of optodes, NIRS characterizes changes in the intensity of attenuated near-infrared light (due to scattering or absorption), resulting from changes in concentration between oxyhemoglobin (HbO₂) and deoxyhemoglobin (Hb) during local neural activity.(for details, click to link)