The thalamic reticular nucleus, unlike all other thalamic nuclei, has no projections to the cerebral cortex. Rather, the reticular nucleus is a sheet of neurons that receive inputs from the cortex and from thalamic projection neurons and send inhibitory (GABA) projections back to the thalamus ( Fig. 16-19 ). Inspection of Figures 16-7 to 16-13 reveals that axons traveling from thalamus to cortex or from cortex to thalamus must traverse the reticular nucleus. As they do so, these fibers give off collaterals to the reticular nucleus. For example, the portion of the reticular nucleus adjacent to VPL/VPM receives convergent inputs from somatosensory fibers on their way to the postcentral gyrus, and from regulatory fibers on their way from the postcentral gyrus to VPL/VPM. The output of each portion of the reticular nucleus goes to that thalamic nucleus from which it receives its input. This makes the reticular nucleus an important source of regulatory input to the thalamus.